Category: Explainers, Myths & How-tos

  • How to Read a Weight-Loss Study Headline in 5 Steps

    How to Read a Weight-Loss Study Headline in 5 Steps

    In short: Before you believe a weight-loss headline, ask five questions: who was studied (people or mice, and people like you?), how many, for how long, compared with what, and who paid. Then look for the absolute numbers behind any percentage. A drug that “cuts heart risk by 20%” lowered the share of people with a heart attack, stroke or heart death from 8.0% to 6.5% in its trial: real and useful, but smaller than the headline sounds.

    Scientists in a high-tech lab conducting research, analyzing data with advanced equipment.
    Photo: Pavel Danilyuk / Pexels

    Weight-loss news moves fast, and much of it starts as a press release, a single small study or an experiment in mice. This guide walks through five checks, each with a real example from the research we use on InstaTuck. It is the same method behind our editorial standards, and it works for any health story. You can find more of our research explainers in the InstaTuck research library and our Learn hub.

    The 5 questions to ask about any weight-loss study

    1. Who was studied?People or animals? And people like you in age, sex, health and weight?
    2. How many?A handful of volunteers or thousands? Small studies swing more by chance.
    3. How long?Weeks or years? Weight and side effects can change after a study ends.
    4. Compared with what?Placebo, another treatment or nothing? And by how much, in absolute terms?
    5. Who paid, and where was it published?Company funding, press release or peer-reviewed journal?

    The National Institutes of Health suggests a very similar checklist for reading health news: was it tested in people, were there enough of them, were they similar to you, was the study long enough, is it the first study to find this, and did someone with a financial interest pay for it. The CONSORT 2025 statement, the international standard for reporting randomized trials, asks researchers to report the same details in a 30-item checklist, so good papers make these answers easy to find.

    Step 1: Who was studied: mice, or people like you?

    Many exciting headlines come from animal or lab studies. They are an important first step, but they often do not carry over to people. When researchers followed 76 highly cited animal studies published in top journals, 37% were later confirmed in human randomized trials, 18% were contradicted, and 45% had never been tested in people at all.

    What happened to 76 highly cited animal studies when tested in people
    What happened to 76 highly cited animal studies when tested in people
    ItemValue
    Confirmed in human trials37%
    Contradicted in human trials18%
    Never tested in people45%

    Studies from leading journals, 1980 to 2000. Shares of the 76 studies.

    Source: Hackam DG, Redelmeier DA. JAMA 2006 (checked on October 7, 2026)

    Brown fat is a good weight-loss example. Small mammals rely on it to make heat, so it looks powerful in rodent studies. In adults, direct measurement found that brown fat burned only about 15 to 25 extra calories a day during mild cold, even in people with plenty of it. Our article on brown fat, cold plunges and saunas tells that story in full.

    Even in human studies, check whether the volunteers resemble you. A trial in young men may not apply to women after menopause, and results in people with type 2 diabetes are often different: in the trials of the newest medicines, people with diabetes usually lost less weight than people without it. The “who was studied” section of a paper, often called “participants” or “eligibility”, tells you.

    Step 2: How many people took part?

    Small studies can find big effects by chance, and those effects often shrink or vanish when the work is repeated with more people. Spot reduction is a clear example. A small 2023 trial in 16 men reported extra trunk-fat loss with long sessions of ab exercises. But a 2022 pooled analysis of 13 studies with 1,158 people found no spot-reduction effect at all. Until the small result is repeated, the bigger body of evidence is the safer guide; our page on whether you can spot-reduce fat explains both.

    Size also decides what a study can detect. A trial of a few hundred people can show average weight change, but rare side effects, such as a problem that affects one person in a thousand, only appear in very large trials or after a treatment is widely used. That is one reason the FDA keeps watching medicines and devices after approval. As a rough rule, be most cautious with a single study of under 100 people and most confident in results repeated across several large trials.

    Step 3: How long did it last?

    Weight usually comes off fastest in the first months and the real test is what happens next. A diet study of 8 weeks cannot tell you whether people stayed on it for a year. Even strong results can change once treatment ends. In the STEP 1 trial, adults on semaglutide 2.4 mg (Wegovy) lost 17.3% of their weight over 68 weeks in the group followed afterward. One year after stopping the medicine and the lifestyle program, they had regained about two-thirds of it and were 5.6% below where they started.

    STEP 1 extension: average weight change on and after semaglutideValues in %
    STEP 1 extension: average weight change on and after semaglutide
    ItemValue
    Week 68, end of treatment17.3%
    Week 120, one year after stopping5.6%

    Percent of starting body weight lost, compared with the start of the trial. Exploratory analysis of a subset of participants.

    Source: Wilding JPH et al., Diabetes, Obesity and Metabolism 2022 (STEP 1 extension, 327 participants) (checked on October 7, 2026)

    That does not mean the medicine failed; it shows that obesity is a long-term condition, which is why the study length matters so much. Our guide to life after stopping a GLP-1 covers what helps. When you read a headline, look for the length in weeks and ask whether anyone was followed after the treatment stopped.

    Step 4: Compared with what, and by how much?

    In most weight-loss trials, the comparison group loses weight too, because everyone gets diet and activity advice. So the number that matters is the difference between the groups. In the trial behind the Plenity capsule, people lost 6.4% of their body weight, which sounds solid, but people taking a look-alike capsule filled with cane sugar lost 4.4%. The device added about 2 percentage points. Our list of FDA-authorized weight-loss devices shows the same pattern across devices.

    Then check whether a percentage is relative or absolute. In the SELECT trial of 17,604 adults with heart disease and overweight or obesity, a heart attack, stroke or heart-related death occurred in 8.0% of people on placebo and 6.5% of people on semaglutide over about three years. That is a 20% relative reduction (the hazard ratio was 0.80), the figure most headlines used. The absolute reduction was 1.5 percentage points: roughly 67 people would need treatment for about three years to prevent one such event, by our arithmetic. Both numbers are true; the absolute one tells you more about your own odds.

    SELECT trial: share of people with a heart attack, stroke or heart deathValues in %
    SELECT trial: share of people with a heart attack, stroke or heart death
    ItemValue
    Placebo8%
    Semaglutide 2.4 mg6.5%

    Mean follow-up 39.8 months. Relative reduction 20% (hazard ratio 0.80); absolute difference 1.5 percentage points.

    Source: Lincoff AM et al., New England Journal of Medicine 2023 (SELECT, 17,604 adults) (checked on October 7, 2026)

    Watch for two different ways of counting in medicine trials, too. The “treatment-regimen” result counts everyone who was randomized, including people who stopped early; the “efficacy” result estimates what would have happened if everyone had stayed on the drug, and it is always higher. Company press releases often lead with the efficacy number. Our retatrutide results explainer shows how one trial produced 25.0% by one method and 28.3% by the other. And an average is not a promise: in any trial, some people lose much more than the average and some lose little.

    Finally, ask what kind of study it is. In a randomized trial, chance decides who gets the treatment, so the groups start out alike. In an observational study, researchers compare people who already differ, such as those who walk more and those who walk less, and other differences can explain the result. Observational findings show links, not proof of cause. Our 10,000 steps article is built on large observational studies and says so.

    Step 5: Who paid, and where was it published?

    Most large medicine trials are paid for by the company that makes the drug; SELECT, for example, was funded by Novo Nordisk. That does not make a result wrong, because big trials are expensive and are registered and peer reviewed. But funding is worth knowing. A Cochrane review of 75 studies found that industry-sponsored drug and device studies reported favorable efficacy results more often than studies with other funding (risk ratio 1.27). We disclose funding when it matters; our fiber supplements comparison, for example, notes that a key psyllium review was written by authors from its manufacturer.

    Where the claim appears matters as much. A peer-reviewed journal paper has been checked by outside experts. A company press release or a conference “topline” result has not, and the full paper may tell a more mixed story. A trial registered in advance on ClinicalTrials.gov lets anyone see what the researchers planned to measure, which makes it harder to cherry-pick results later. Supplement marketing is the extreme case: “clinically studied” can refer to a tiny, unregistered study of one ingredient at a different dose. Our guides on how to read a supplement label and “Nature’s Ozempic” supplements show what to look for.

    How to find the study behind a headline

    You do not need a science degree to check a source. A good news story names the journal, the lead author or the trial name. Search that name on PubMed, the free database run by the National Library of Medicine, and you will usually find the abstract, a one-paragraph summary with the methods and main numbers. For trials, search the trial name or its NCT number on ClinicalTrials.gov: the record shows how many people were planned, how long the trial runs, what the main outcome is, who sponsors it and whether results have been posted.

    When you open an abstract, read it in this order: the methods (who, how many, how long, compared with what), then the results (look for numbers in both groups, not just the difference), then the conclusions, and finally the funding line, which often appears at the end. If a story gives no way to find the study at all, or links only to a product page, treat the claim as unverified. When we write about a study on InstaTuck, we link the paper or the official record in our sources so you can check it yourself.

    Putting it together: one headline, five checks

    Imagine the headline “New injection wipes out 25% of body weight”. Run the checks. Who: adults with obesity and without diabetes, in a large trial. How many: 2,339. How long: 80 weeks. Compared with what: placebo, which gave 3.9%, so the difference is about 21 points, counting everyone who started. Who paid and where: the maker, with results published in a major peer-reviewed journal. That is strong evidence for the average weight change. It still leaves questions a headline skips: side effects, what happens after stopping, how it compares with existing medicines, and whether the FDA approves it at all. For drugs still in trials, see our tracker of treatments awaiting FDA decisions and our monthly news roundup.

    The same five questions protect you from the other end of the market: before-and-after photos and testimonials skip every step at once. Our article on before-and-after photos explains why, and our list of weight-loss myths science has busted shows the method at work. When a study does seem to fit your situation, take it to your clinician; they can tell you whether it applies to you.

  • The 10,000 Steps Myth: How Many Steps You Really Need

    The 10,000 Steps Myth: How Many Steps You Really Need

    In short: You do not need 10,000 steps a day for your health to benefit. The number began as the name of a Japanese pedometer in 1965, not as a research finding. Large studies now link the biggest drop in risk of early death to the range from very few steps up to about 7,000 to 8,000 a day, with benefits leveling off around 6,000 to 8,000 for adults over 60 and 8,000 to 10,000 for younger adults. For weight loss, steps help most as part of a plan with eating changes.

    Old people, man, woman, love, nature, path, walk, harmony, hand in hand, arm-in-arm, people, pair, togetherness, together, as a couple, older, old, relationship, man and woman, silhouettes, lovers, fa
    Photo: Marzena7 / Pixabay

    Fitness trackers often set 10,000 steps as the default goal, and many people feel they have failed if they fall short. This article explains where the number came from, what the biggest step studies found, and how steps fit into weight loss. For a practical walking plan, see our guide to walking for weight loss, which has a 6-week plan and pace targets.

    Steps at a glance

    Checked on October 7, 2026

    Where 10,000 steps came from

    The goal traces back to Japan in the 1960s. In 1965, a company sold a pedometer called the manpo-kei, which translates as “10,000 steps meter”. Dr. I-Min Lee, a Harvard epidemiologist who has studied step counts and health, told Harvard Health Publishing that “the name was a marketing tool”. A 2004 review by step researchers traced the figure to Japanese walking clubs and a business slogan, and said that 10,000 steps was a reasonable estimate of daily activity for healthy adults but might not be sustainable for some groups, including older adults and people with chronic conditions.

    In other words, 10,000 was a round, memorable number that happened to sit near what active people do. It was never tested as a threshold, and for decades nobody checked whether fewer steps would bring most of the benefit. Our history of exercise fads shows how often fitness targets begin as marketing.

    What the big step studies found

    Researchers finally tested the question with step counters worn by tens of thousands of people, then followed them for years. Three studies stand out.

    Older women (2019). In the Women’s Health Study, 16,741 women with an average age of 72 wore a step counter for a week and were followed for about four years. Women in the lowest group averaged 2,718 steps a day. Those averaging 4,363 steps had a 41% lower risk of dying during the study, and the risk kept falling up to about 7,500 steps a day, then leveled off. How fast they walked mattered less once the total number of steps was taken into account.

    US adults (2020). In a national sample of 4,840 adults aged 40 and older, followed for about 10 years, taking 8,000 steps a day was linked to a 51% lower risk of death from any cause than taking 4,000, and 12,000 steps to a 65% lower risk, after adjusting for age, health conditions, body mass index and other factors.

    Fifteen studies pooled (2022). The largest analysis combined data from 15 studies and 47,471 adults, followed for a median of 7.1 years. Compared with the least active quarter, who averaged 3,553 steps a day, people averaging 5,801 steps had a 40% lower risk of death, 7,842 steps a 45% lower risk, and 10,901 steps a 53% lower risk. The curve flattened: for adults 60 and older, risk stopped falling much beyond 6,000 to 8,000 steps a day; for younger adults, beyond 8,000 to 10,000.

    Risk of death by daily steps, compared with the least active group (set at 100)
    Risk of death by daily steps, compared with the least active group (set at 100)
    ItemValue
    3,553 steps a day100
    5,801 steps a day60
    7,842 steps a day55
    10,901 steps a day47

    Adjusted hazard ratios x 100 for each quarter of daily steps (median steps shown), median follow-up 7.1 years. Observational: shows a link, not proof that steps caused the difference.

    Source: Paluch AE et al., The Lancet Public Health 2022 (15 cohorts, 47,471 adults) (checked on October 7, 2026)

    The biggest gain comes from moving out of the least active group. Going from about 3,500 to about 5,800 steps was linked to a 40% lower risk; the extra 5,000 steps after that added only about 13 more points. If you are taking very few steps now, a modest increase is where most of the benefit appears.

    The 2025 update: about 7,000 steps for many health outcomes

    A 2025 review in The Lancet Public Health looked beyond death to other health outcomes, using 57 studies from 35 groups of people. Compared with 2,000 steps a day, about 7,000 steps a day was linked to a 47% lower risk of death from any cause, a 25% lower risk of heart disease, a 37% lower risk of dying from cancer and a 14% lower risk of type 2 diabetes. For death, heart disease, dementia and falls, the benefit curve bent at around 5,000 to 7,000 steps, meaning each extra thousand steps added less after that point.

    About 7,000 vs 2,000 steps a day: how much lower the risk wasValues in %
    About 7,000 vs 2,000 steps a day: how much lower the risk was
    ItemValue
    Death from any cause47%
    Death from heart disease47%
    Death from cancer37%
    Heart disease25%
    Type 2 diabetes14%

    Percent lower risk, from pooled hazard ratios. Observational studies; some outcomes rest on only 3 to 6 studies.

    Source: Ding D et al., The Lancet Public Health 2025 (systematic review, 57 studies) (checked on October 7, 2026)

    It also helps to know what these studies counted. Participants wore a research-grade step counter during waking hours for about a week; in the US study, people wore it for an average of 5.7 days and 14.4 hours a day. Every step counted, from walking to the bus to housework, not only planned walks. So the totals are comparable to an all-day count on your phone or tracker, though readings can vary from one device to another. A single week was used to describe each person’s habits for years afterward, which is another reason to treat the exact thresholds as approximate.

    One important caution applies to all of these numbers. They come from observational studies: people who walk more may differ in many ways, such as being healthier to begin with. The researchers adjust for what they can, but these studies show strong links, not proof that each extra step causes the benefit. Our guide on how to read a weight-loss study headline explains the difference.

    A woman walks her dog along the beach at sunset, creating a serene silhouette against the colorful sky.
    Photo: George Zografidis / Pexels

    Steps and weight loss

    Steps on their own move the scale only a little. In a meta-analysis of nine pedometer-based walking programs without any diet change, 307 participants lost 1.27 kg (about 2.8 lb) on average over a median of 16 weeks, or about 0.05 kg a week; longer programs led to more loss. That is modest, but it adds up and comes with the health benefits above. Programs like these typically raise daily steps by about 2,000 to 2,500.

    The American College of Sports Medicine has found that 150 to 250 minutes a week of moderate activity brings modest weight loss, and that larger amounts, or activity combined with eating changes, do more. Walking is also one of the best tools for keeping weight off once you have lost it; our guide to maintaining weight loss explains why. For the weight-loss side, pair your steps with a steady calorie deficit and some strength training to protect muscle. You can see what a walk burns at your weight with our calories burned calculator.

    Steps or minutes: how they line up with the guidelines

    The Physical Activity Guidelines for Americans are written in minutes, not steps: 150 to 300 minutes a week of moderate activity, such as brisk walking, plus muscle-strengthening activity on two or more days. Step researchers have found that about 100 steps a minute is a common marker of moderate-intensity walking for adults. So 30 minutes of brisk walking adds roughly 3,000 steps on top of the steps you take in daily life, by that cadence.

    Pace is a bonus rather than a requirement. In the 2022 pooled study, the link between faster stepping and lower risk weakened once total steps were counted, although the fastest 30 minutes of the day still mattered somewhat. Walking faster does burn more per minute, as our walking vs running comparison shows, and it can help you fit your minutes into a shorter time.

    Is 10,000 steps a bad goal, then?

    Not at all. It is just not the minimum. The same 2004 review that traced the number to Japan proposed rough bands that are still useful: under 5,000 steps a day as a “sedentary” marker, 5,000 to 7,499 as typical daily activity without exercise, 7,500 to 9,999 as “somewhat active”, and 10,000 or more as “active”. A 2011 update found that healthy adults take anywhere from about 4,000 to 18,000 steps a day. If you already reach 10,000 and enjoy it, there is no reason to cut back; for adults under 60, the 2022 pooled study saw benefit continue up to about that level.

    The problem with 10,000 is what it does to people far below it. If your average is 3,000 steps, a goal of 10,000 can feel impossible and lead you to give up, even though the research suggests that reaching 5,000 or 6,000 would already be linked to a large drop in risk. The 2004 reviewers made the same point: goals based on gradual increases from your own baseline were showing promise and are easier to sustain.

    Age matters as well. In the study of older women, the benefit leveled off at about 7,500 steps a day, and in the 2022 analysis the plateau for adults 60 and older came at 6,000 to 8,000. For many older adults, a realistic target in that range, plus balance and strength exercises, is a better fit than chasing a five-figure number.

    How to pick a step goal that works for you

    There is no single number for everyone. A useful starting point is your own average: check what your phone or tracker shows for the last week, then add a little.

    Build your step goal in 1-2-3

    1. Find your baselineLook at your average daily steps over the past 7 days.
    2. Add 1,000 to 2,000Aim for that for two weeks, for example with a 10- to 15-minute walk after a meal.
    3. Move toward 7,000 to 8,000Then add more if you enjoy it; for younger adults, benefit kept growing to about 8,000 to 10,000.

    Small changes count: a walk after dinner, a phone call on the move, or an indoor walking pad on bad-weather days. Our guide to walking pads and our picks of fitness trackers and walking and step-counter apps can help if you want tools, though none is required. Step counts from wrist devices are estimates, and our fitness tracker vs smart ring comparison explains how accurate they tend to be. If steps are hard because of joint pain, our list of low-impact workouts has options that count toward the same weekly minutes.

    Steps are one measure among many. Our guide to tracking progress without the scale covers others, and our check of viral workout trends looks at Japanese walking and other walking-based fads. If you have a health condition that limits walking, ask your clinician what amount is right for you.

  • Brown Fat, Cold Plunges and Saunas: Do They Help Weight Loss?

    Brown Fat, Cold Plunges and Saunas: Do They Help Weight Loss?

    In short: Not much, on their own. Adults do have some brown fat, and cold switches it on, but careful measurements found it burns only about 15 to 25 extra calories a day in mild cold, less than a 10-minute brisk walk. Very cold water raises your calorie burn for as long as you shiver, yet no trial has shown that cold plunges lead to meaningful weight loss. The weight you lose in a sauna is sweat, and it comes back when you drink. Both can be pleasant habits, but they are not weight-loss tools.

    A woman relaxing in a sauna wrapped in a towel, experiencing ultimate wellness and comfort.
    Photo: Andrea Piacquadio / Pexels

    Cold plunges, ice baths and “cold therapy” are everywhere on social media, often with the promise that they turn on fat-burning brown fat and fire up your metabolism. Saunas come with their own claims about sweating off pounds. This article checks those claims against human studies. For the bigger picture of how your body uses energy, see our guide to metabolism and weight; for foods sold as metabolism boosters, see metabolism-boosting foods: fact or fiction.

    Cold, heat and calories at a glance

    Checked on October 7, 2026

    What brown fat is, and how much of it adults have

    Most body fat is white fat, which stores energy. Brown fat is different: it is packed with mitochondria and a protein called UCP1 that lets it turn energy straight into heat. Babies and small mammals depend on it to stay warm. Until 2009, most scientists thought adults had almost none. That year, studies in the New England Journal of Medicine showed that many adults do have active brown fat, mainly in a region from the front of the neck down into the chest.

    How much depends on who you are and how cold it is. On PET-CT scans done for other medical reasons in nearly 2,000 people, clear brown-fat deposits showed up in 7.5% of women and 3.1% of men; they were less common in older people, in people taking beta-blockers and when the weather was warm. When researchers deliberately cooled 24 young men to 16°C (61°F), brown-fat activity appeared in 23 of them, but it was lower in men with overweight or obesity than in lean men. So brown fat is real and cold does activate it. The question is how much energy it actually uses.

    How many calories does brown fat burn?

    Much less than the headlines suggest. A 2013 study measured oxygen use directly inside brown fat with PET scans in 25 adults at rest and in mild cold (15.5°C, about 60°F). In the people with the most brown fat, about 59 grams on average, it added roughly 3 calories a day at rest and about 6 calories a day in the cold, by direct measurement. The authors concluded that cold-activated brown fat accounts for about 15 to 25 calories a day even in people with relatively large deposits, and called it “a minor source” of heat production in humans. Most of the extra energy you spend in the cold comes from muscles, through shivering and tensing.

    Extra calories above resting: brown fat in mild cold vs a brisk walkValues in kcal
    Extra calories above resting: brown fat in mild cold vs a brisk walk
    ItemValue
    Brown fat in mild cold, a whole day (upper estimate)25 kcal
    Brisk walk, 10 minutes44 kcal
    Brisk walk, 30 minutes133 kcal

    Walking values are our arithmetic for a 154-lb (70-kg) adult: (4.8 – 1 MET) x 70 kg x time in hours, calories above resting. Brown-fat value is the study's upper estimate for people with large brown-fat deposits.

    Source: Muzik O et al., J Nucl Med 2013 (brown fat); 2024 Adult Compendium of Physical Activities, code 17200, walking 3.5-3.9 mph, 4.8 METs (walk) (checked on October 7, 2026)

    Our calories burned calculator uses the same Compendium values, so you can check the walking numbers for your own weight and pace. For why a short walk adds up over time, see our guide to walking for weight loss.

    Can you grow more brown fat with regular cold?

    Somewhat, in the lab. In a Dutch study, 10 days of mild cold acclimation raised brown-fat activity and non-shivering heat production in volunteers, and people reported feeling more comfortable in the cold and shivering less. In a Japanese randomized study, 12 young adults with little brown fat spent 2 hours a day at 17°C (63°F) for six weeks, while 10 others kept to their normal routine. The cold group’s brown fat became more active and their body fat fell by about 0.7 kg (1.5 lb), or 5.2% of their fat mass; the control group’s did not change. Their body weight, however, did not change significantly.

    Those are encouraging signals for research, and they come with big caveats: very small groups, two hours of cold every day (about 84 hours in total) and no change on the scale. In another small study, 10 days at 14-15°C (57-59°F) improved insulin sensitivity by about 43% in eight people with type 2 diabetes, but brown fat itself changed only a little; most of the effect was in muscle. None of these studies tested cold plunges, and none showed weight loss you would notice. Our guide to how to read a weight-loss study headline explains why small, short studies like these are a starting point, not an answer.

    Couple walking hand-in-hand along a tropical beach at sunset, creating a romantic ambiance.
    Photo: Andres Idda Bianchi / Pexels

    Cooler rooms, cold showers and “brown fat” supplements

    What about everyday cold, such as a cooler bedroom or a cold shower? The Dutch researchers who ran the 10-day acclimation study suggested that a home or office temperature that varies, with frequent mild cold, might be an acceptable way to raise energy use a little. That is an idea for further research, not a tested weight-loss method, and the amounts involved are small. Comfort and sleep matter too; if a cold room keeps you awake, the trade-off is not worth it.

    The same Japanese team also tested capsinoids, mild relatives of the compound that makes chili peppers hot. Six weeks of daily capsinoids raised cold-induced energy use in a small group of volunteers, but the study did not report weight loss from them. Supplements sold to “activate brown fat” rely on this kind of early evidence. Our article on metabolism-boosting foods shows how small the effects of chili, caffeine and green tea are in practice, and our guide to fat burners explains why the label claims run far ahead of the research.

    The pattern is the same each time. Brown fat is a fascinating area of research, and scientists hope it could one day lead to treatments, but nothing you can do at home has been shown to turn it into a meaningful weight-loss engine. The big levers are still what you eat and how much you move.

    Cold plunges and ice baths

    Cold water pulls heat from the body much faster than cold air, so your body works hard to stay warm. In a classic study, young men sat in water up to the neck for one hour. At 32°C (90°F), their metabolic rate did not change. At 20°C (68°F), it rose by 93%. At 14°C (57°F), it rose by 350%, along with large jumps in noradrenaline, heart rate and blood pressure. That is a real increase in calorie burn, but it lasts only while you are cold, it comes mostly from shivering, and an hour at that temperature is far beyond a typical 2- to 5-minute plunge.

    Rise in metabolic rate during 1 hour of head-out water immersionValues in %
    Rise in metabolic rate during 1 hour of head-out water immersion
    ItemValue
    32°C (90°F)0%
    20°C (68°F)93%
    14°C (57°F)350%

    Small laboratory study in young men; compared with sitting in room-temperature air. The rise lasts only during the cold exposure.

    Source: Srámek P et al., European Journal of Applied Physiology 2000 (checked on October 7, 2026)

    We found no randomized trial showing that regular cold plunges or cold-water swimming cause meaningful weight loss. A 2022 review of 104 studies on voluntary cold-water immersion found signs that it may change body fat and improve insulin sensitivity, but said clear conclusions were hampered because most studies were small, often in one sex, and used different temperatures; the authors called the topic “a continuing subject of debate”. A 2023 randomized cross-over trial in 18 rugby players found no effect of regular cold or hot water immersion after weight training on body composition. Winter swimmers may also simply be healthier people to begin with.

    Many people enjoy cold plunges for how they feel afterward, and athletes use them for recovery; those are separate questions from weight. Our check of viral workout trends covers other social-media favorites with the same evidence lens.

    Saunas: what the scale shows is water

    A sauna makes you sweat, and sweat weighs something. In a study of 674 university students, two 10-minute sessions in a 90°C (194°F) dry sauna reduced body weight by 0.37 kg (about 0.8 lb) in women and 0.50 kg (about 1.1 lb) in men on average; people with a higher BMI lost more. That weight is water, and it returns as soon as you rehydrate. The researchers’ practical advice was about the opposite of weight loss: people with a higher BMI should take particular care to replace fluids.

    Average weight lost in two 10-minute dry sauna sessions (it is water)Values in kg
    Average weight lost in two 10-minute dry sauna sessions (it is water)
    ItemValue
    Women (326)0.37 kg
    Men (348)0.50 kg

    90°C dry sauna, 674 sedentary students aged 19-20. Body-mass loss from sweating; regained with fluids.

    Source: Podstawski R et al., The Scientific World Journal 2014 (checked on October 7, 2026)

    Sweating does not “detox” fat either; the kidneys and liver handle waste, as our article on detox teas and cleanses explains. And sauna suits, which make you sweat during exercise, have a long history as a weight-loss gimmick, covered in our history of weight-loss hoaxes.

    Saunas may still be good for you in other ways. In a Finnish study that followed 2,315 middle-aged men for about 20 years, those who used a sauna 4 to 7 times a week had a lower risk of sudden cardiac death than those who went once a week, after adjusting for other risk factors. That is an observational link in a population where sauna is a lifelong habit, not proof that saunas cause the benefit, and it says nothing about weight. A review of sauna research found it well tolerated by healthy people and by people with stable, treated heart conditions, with one caution: blood pressure medicines can make you light-headed when you stand up afterward.

    What does move the needle

    The approaches with strong evidence are less exotic: a steady calorie deficit, regular activity you enjoy, strength training to protect muscle, enough sleep and, for some people, medical treatment. If you like cold plunges or saunas, there is no need to stop; just do not count them as your weight-loss plan. Our list of weight-loss myths science has busted and our guide to keeping weight off are good next reads.

    If you enjoy the cold or the heat

    1. Keep it safeShort cold exposures, never alone, no alcohol; drink water before and after a sauna.
    2. Count it as recovery, not exerciseAdd a walk or a strength session for the calorie side.
    3. Check with your clinicianEspecially with heart disease, high blood pressure, pregnancy or diabetes.
  • Questions to Ask a Bariatric Surgeon (and How to Check Credentials)

    Questions to Ask a Bariatric Surgeon (and How to Check Credentials)

    In short: Before bariatric surgery, check three things and ask about five more. Check the surgeon (certified by the American Board of Surgery, with a license in good standing), the center (accredited by the American College of Surgeons’ MBSAQIP program) and the team (dietitian, behavioral health and long-term follow-up). Then ask which procedure fits you and why, what the risks are, how complications are handled day and night, what follow-up and vitamins you will need for life, and what the whole process costs. This page explains each step with sources from ASMBS, the American Board of Surgery and the MBSAQIP standards, and ends with a checklist you can print.

    Three friends walking on a dirt path surrounded by lush greenery on a bright sunny day.
    Photo: Katia Damyan / Pexels

    New to the options? Our bariatric surgery guide explains the operations and who they are generally considered for, and our weight-loss procedures comparison sets surgery, endoscopic procedures and balloons side by side. Our guide to finding a bariatric surgeon shows where to search for surgeons and accredited centers; this page is the list of questions to take into the consultation once you have found them. InstaTuck does not rank or refer to surgeons, and this is general education: only a surgical team that has evaluated you can say whether surgery is right for you.

    Bariatric surgery in the U.S., in numbers

    Checked on October 7, 2026

    Three stages to plan for

    1. Before the first visitWrite down your weight and health history, medicines and goals; check the surgeon's certification and the center's accreditation.
    2. At the consultationAsk about the procedure options, the team, the risks, follow-up, vitamins and the full cost.
    3. Before you agree to a dateGet written answers and estimates, check your insurance rules, and plan help at home and the years of follow-up.

    Before the first visit: what to write down

    Programs usually start with an information session or consultation. Walking in with your history written down means nothing important gets missed, and it helps you compare programs fairly.

    • Your weight history and BMI. The 2022 guidelines from ASMBS and the International Federation for the Surgery of Obesity and Metabolic Disorders (IFSO) recommend metabolic and bariatric surgery at a BMI of 35 or more, whether or not you have related conditions, and say it should be considered from a BMI of 30 for people with metabolic disease such as type 2 diabetes. Lower thresholds apply to people of Asian descent. These are general criteria, not a personal recommendation. Our BMI calculator is a starting point only.
    • Health conditions. Diabetes, high blood pressure, sleep apnea, reflux, heart, lung, kidney or liver disease, blood clots and past abdominal surgery all affect which procedure is suggested.
    • Every medicine and supplement. Include any GLP-1 medicine such as Wegovy or Zepbound. The labels warn about breathing stomach contents into the lungs under general anesthesia or deep sedation, so the surgical and anesthesia teams need to know.
    • What you have tried. Diets, programs and medicines, with dates. Medicare’s national coverage policy, for example, asks for a BMI of 35 or more, at least one related condition and previous unsuccessful medical treatment.
    • Your insurance details. Ask your plan in writing what it requires before approval. Our insurance guide lists the questions to ask.
    • Life plans. Pregnancy plans matter: clinical guidelines advise avoiding pregnancy for 12 to 18 months after surgery.

    How to check credentials: the surgeon, the center, the team

    ASMBS says medical organizations recommend that surgery be done by a board-certified surgeon with specialized experience or training in bariatric and metabolic surgery, at a center with a multidisciplinary team for follow-up care. You can check most of this yourself, for free, before the first appointment.

    1. The surgeon: board certification

    The American Board of Surgery (ABS), founded in 1937, says its website is the primary source to verify a surgeon’s certification status. Its check a certification tool answers “Is my surgeon board certified?” A certified surgeon has completed at least five years of training after medical school, met the ABS training requirements and passed its exams; to stay certified, surgeons must keep up continuing education and practice improvement and pass an online assessment every two years. The ABS also offers a Focused Practice Designation in metabolic and bariatric surgery; under the 2026 MBSAQIP standards, surgeons who hold it automatically qualify as MBSAQIP-verified. Also confirm that the surgeon holds an active license with your state medical board, and look for any public disciplinary actions it lists.

    A directory listing is not verification. Membership in ASMBS, searchable through its find a provider directory, shows involvement in the specialty, but it is not the same as board certification or center accreditation.

    2. The center: MBSAQIP accreditation

    The Metabolic and Bariatric Surgery Accreditation and Quality Improvement Program (MBSAQIP), a program of the American College of Surgeons whose standards are written with ASMBS, reviews inpatient and outpatient centers through independent, voluntary peer evaluations. You can look up accredited centers with the ACS hospital search, and ASMBS notes that some insurers require MBSAQIP accreditation. Its 2026 standards took effect on July 1, 2026, replacing the 2022 version. Accreditation lasts three years, after a site visit, and centers report on compliance every year in between.

    Accreditation comes in levels, and the level tells you which patients a center is set up for. Comprehensive Centers care for adults and can perform every ASMBS-endorsed procedure. Low Acuity Centers and accredited outpatient surgery centers are limited to adults aged 18 to 65 who meet selection rules; at Low Acuity Centers these include a BMI under 55 for men and under 60 for women, no organ failure or transplant, and no previous weight-loss surgery (apart from band or port revisions and emergencies). Teenagers need a center with adolescent qualifications. Each level also has a minimum yearly case volume:

    Minimum procedures a year for each MBSAQIP accreditation levelValues in procedures
    Minimum procedures a year for each MBSAQIP accreditation level
    ItemValue
    Comprehensive Center (stapling procedures)50 procedures
    Low Acuity Center25 procedures
    Ambulatory Surgery Center25 procedures
    Adolescent Center (stapling procedures)15 procedures

    Adolescent Centers below 15 stapling cases need an MBSAQIP-verified co-surgeon on each case. Volume is one requirement among many, not a measure of quality on its own.

    Source: American College of Surgeons, Optimal Resources for Metabolic and Bariatric Surgery, 2026 Standards (checked on October 7, 2026)

    The standards also set requirements for the surgeon who leads the program (the MBS Director), who must be “MBSAQIP-verified”. Other surgeons at the center may seek verification but don’t have to, so it is fair to ask whether yours is verified.

    What MBSAQIP asks of a verified surgeon (2026 standards)

    Checked on October 7, 2026

    3. The team

    Accredited centers must give access or referral to registered dietitians, licensed behavioral health professionals (psychologists, psychiatrists or social workers), physical or exercise therapists, nurses or advanced practice providers, and a consistent operating room team. They must have bariatric call coverage 24 hours a day, 365 days a year, and offer supervised support groups at least every two months. Ask to meet the team, or at least to know who they are.

    • Are you certified by the American Board of Surgery? Do you hold the Focused Practice Designation in metabolic and bariatric surgery, or MBSAQIP surgeon verification?
    • Is this center MBSAQIP accredited, and at which level? Does that level fit my age, BMI and health?
    • Where did you train in bariatric surgery, and how many of the procedure you suggest for me do you do each year?
    • Who is on my team (dietitian, psychologist or counselor, exercise specialist, obesity medicine doctor), and when will I see each of them?
    • Who answers the phone at night and on weekends after I go home?

    Questions about which procedure, and why

    The sleeve made up 58.2% of an estimated 270,089 U.S. procedures in 2023 and gastric bypass 23.4%, according to ASMBS; revisions of earlier operations were 11.9%. The 2026 MBSAQIP standards ask each surgeon’s patient education to cover all procedure options the center offers, the center’s own case volume for each, national outcome data from the MBSAQIP registry, and a clear explanation of the goals, risks, benefits and alternatives of each procedure as part of informed consent. That gives you the right to ask for numbers. Our pages on the gastric sleeve and gastric bypass, and sleeve vs bypass compared, help you follow the answers.

    • Which procedures do you offer, and which do you suggest for me? Why that one, given my health, reflux, diabetes and plans?
    • How many of each did this center do last year, and how do your results compare with the national MBSAQIP data?
    • Is the operation reversible? What happens if it doesn’t work as hoped?
    • What are the alternatives, including an endoscopic sleeve, medicines, or waiting?
    • How much weight do people like me usually lose, and how much do they usually regain over time?

    Questions about risks and complications

    ASMBS’s 2025 fact sheet puts the risk of death at about 0.1% and major complications at about 4%, varying by procedure. In a U.S. study of 65,093 adults across 41 health systems (PCORnet, 2018), major adverse events within 30 days happened after 5.0% of gastric bypasses, 2.6% of sleeves and 2.9% of bands. Over the longer term, the NIDDK says about one in three people needs a follow-up procedure or hospital stay within five years, more often after bypass. Different studies, not a head-to-head comparison:

    Major adverse events within 30 days, by procedure (PCORnet, 65,093 adults)Values in %
    Major adverse events within 30 days, by procedure (PCORnet, 65,093 adults)
    ItemValue
    Gastric bypass5%
    Sleeve gastrectomy2.6%
    Adjustable band2.9%

    Observational study of 41 U.S. health systems; your own risk depends on your health and the center. Ask for the center's own numbers.

    Source: Arterburn D et al., Annals of Internal Medicine 2018 (PCORnet Bariatric Study) (checked on October 7, 2026)

    Accredited centers must have a defined process for spotting warning signs early, and the standards name a fast heart rate, fever, shortness of breath, severe belly pain and vomiting. Your discharge instructions should tell you which of these to call about and when to go to an emergency room.

    • What are the most common and the most serious complications for someone like me, and how often do they happen here?
    • What do you do to lower the risk of blood clots, leaks and breathing problems?
    • Which symptoms after surgery mean I should call you, and which mean an emergency room? If I go to a different hospital, who will they call?
    • What should I do about my GLP-1 or other medicines before and after surgery?
    • If I need another operation later, will you do it, and what would it cost?

    Questions about nutrition, vitamins and follow-up

    Surgery is the start of a lifelong plan. Clinical guidelines from AACE, The Obesity Society and ASMBS (2019) describe a staged return from liquids to regular textures over about six to eight weeks, at least 60 grams of protein a day, lifelong vitamin and mineral supplements, and at least 150 minutes of activity a week. ASMBS nutrition guidance (2016) recommends lab checks every three to six months in the first year and then yearly. The MBSAQIP standards require accredited centers to follow every patient at 30 days, 6 months and 1 year, and to keep trying to reach patients every year after that. Our guide to life after bariatric surgery walks through each stage, and our protein calculator gives a general range to discuss with your dietitian.

    • What will I eat in the weeks before and after surgery, and who will guide me through each stage?
    • Which vitamins and minerals will I need for life, and who orders and checks my labs?
    • How many years of follow-up visits are included, and what happens if I move?
    • Is there a support group, and when does it meet?
    • If weight comes back, what support do you offer, from nutrition help and medicines to revision surgery?

    Questions about cost and insurance

    ASMBS cites an average cost of about $17,000 to $26,000 (an undated page, checked on October 7, 2026). Medicare covers gastric bypass, duodenal switch and adjustable banding nationally for people who meet its criteria, and leaves the sleeve to its regional contractors; commercial plans vary, and some exclude surgery. Some plans still require a supervised diet before approval, even though the 2022 ASMBS/IFSO guidelines call insurer-mandated preoperative weight loss “discriminatory, arbitrary, and scientifically unfounded”. Our cost hub helps you build a full budget.

    • Can I have a written, itemized estimate for the surgeon, anesthesia, hospital, tests, dietitian and follow-up visits?
    • What does my plan require before approval, and will your office help with the paperwork?
    • What costs will I keep paying after surgery (vitamins, labs, visits), and which are covered?
    • Who pays if I have a complication or need a revision?

    Red flags

    • A surgery date offered before any evaluation, nutrition visit or behavioral health assessment.
    • No clear answer about board certification, the center’s accreditation, or who handles complications at night.
    • No written plan for follow-up visits, vitamins and lab checks.
    • Only one procedure offered, with no discussion of alternatives, or pressure to decide quickly.
    • Packages that bundle travel and surgery with nothing arranged for care when you get home.

    Printable checklist

    Print this page or copy the list into your phone’s notes. Take it to each consultation and write the answers next to each item, so you can compare programs side by side.

    Before bariatric surgery: my checklist

    Check before the visit

    • ☐ Surgeon’s status on the American Board of Surgery’s “check a certification” page
    • ☐ Active license with my state medical board, and any public actions
    • ☐ Center listed as MBSAQIP accredited in the ACS hospital search, and at which level
    • ☐ What my insurance requires before approval, in writing

    Bring with me

    • ☐ Weight history, BMI and what I have tried before
    • ☐ All medicines and supplements, including any GLP-1
    • ☐ Health conditions, past surgeries and pregnancy plans

    Ask

    1. ☐ Are you board certified in surgery? Are you MBSAQIP-verified or do you hold the bariatric Focused Practice Designation?
    2. ☐ What is this center’s MBSAQIP level, and does it fit me?
    3. ☐ Which procedure do you suggest for me, why, and what are the alternatives?
    4. ☐ How many of these does the center do each year, and how do results compare with national data?
    5. ☐ What are the main risks for me, and how are complications handled day and night?
    6. ☐ Who is on my team: dietitian, behavioral health, exercise, obesity medicine?
    7. ☐ What do I do about my GLP-1 and other medicines before and after?
    8. ☐ Which vitamins and labs will I need for life, and who checks them?
    9. ☐ How many years of follow-up are included? Is there a support group?
    10. ☐ What is the full written cost, including complications and revisions?
    11. ☐ Who do I call after hours, and which symptoms mean the emergency room?

    Still deciding between surgery and medicines? Our comparison of GLP-1 medicines vs bariatric surgery sets out the evidence, and an obesity medicine doctor can help you weigh options before and after surgery. The find a provider hub explains which professional does what, and our history of bariatric surgery shows how the operations and their safety have changed.

  • Detox Teas and Cleanses: What They Do (and Don’t) for Weight

    Detox Teas and Cleanses: What They Do (and Don’t) for Weight

    In short: Detox teas and cleanses can make the scale drop for a few days, but mostly through water and stool, not fat. Many “slimming” teas contain laxatives such as senna, and studies show that even extreme laxative use cuts calorie absorption by only about 12%. Juice cleanses work only because they are very low in calories, and the weight tends to return once normal eating resumes. Regulators have also acted against detox tea marketing: the FTC settled with Teami in 2020 over unsupported weight-loss claims, and the FDA has found the banned drug sibutramine in some “slim” teas.

    This page looks at what is actually in detox teas and cleanse kits, what each ingredient does to your body, and what the FDA and FTC have done about them. For pills and capsules sold for weight loss, see our weight-loss pills guide; for eating well without a cleanse, start at our nutrition hub. This is general education, not medical advice: talk with your clinician before using any laxative or cleanse, especially if you take medicines or have a health condition.

    What “detox” products promise

    The pitch is usually the same: modern life fills your body with “toxins”, the toxins make you bloated and heavy, and a tea, juice program or colon cleanse flushes them out so you feel lighter and lose weight. Products come as teatoxes (often a “morning” tea and an “evening” tea), juice cleanses of 3 to 10 days, powders, and colon cleansing kits or procedures. Social media made them famous, often through influencer posts.

    The National Center for Complementary and Integrative Health (NCCIH), part of the NIH, summarizes the science plainly: a 2015 review found “no compelling research” supporting detox diets for weight management, and a 2017 review noted that any early weight loss comes from eating very few calories and is usually regained afterward. The 2015 review also found no randomized trials testing commercial detox diets in people, and NCCIH notes that the FDA and FTC have acted against several detox and cleansing products for hidden ingredients, false disease claims or unapproved colon-cleansing devices.

    What’s actually in the cup: ingredient by ingredient

    Labels vary, but most detox and slimming teas combine three kinds of ingredient. None of them removes body fat.

    Ingredient typeCommon examplesWhat it doesEffect on body fatWatch out for
    Stimulant laxativesSenna (often listed as senna leaf or sennosides), cascaraMakes the bowel move faster; more frequent, looser stoolsNone: even extreme purging cut calorie absorption by about 12%Cramps, diarrhea, dehydration; NIH advises no more than 1 week of senna without a doctor; dependence with long use
    Diuretic herbsDandelion leaf, othersMore frequent urination for a few hoursNone: the loss is water, which returns when you drinkDehydration, especially with heat, exercise or other diuretics
    Caffeine sourcesGreen tea, yerba mate, guaranaMild stimulant; slightly higher energy useVery small: catechins plus caffeine added about 100 calories a day in lab studiesJitters, poor sleep, fast heartbeat; FDA cites 400 mg a day as generally safe for most adults
    Hidden drugs (in some products)Sibutramine, phenolphthaleinNot listed on the label; found by FDA testingNot a reason to use them: sibutramine was withdrawn in 2010Raised blood pressure and heart rate; dangerous with heart disease

    Laxatives empty your bowel, not your fat cells

    Most of the weight lost on a teatox is the contents of your gut and the water that goes with it. A carefully measured 1983 study in the Annals of Internal Medicine tested this directly: in bulimic patients who used laxatives and in healthy young women, even extreme purging that produced 4 to 6 liters of diarrhea reduced calorie absorption by only about 12% of what they ate. The authors concluded that the idea of using laxatives for weight control “is unsound”.

    Even with extreme laxative purging, most calories were still absorbed
    Even with extreme laxative purging, most calories were still absorbed
    ItemValue
    Calories still absorbed88%
    Calories lost to purging12%

    88% is 100% minus the reported reduction of about 12% of calorie intake.

    Source: Bo-Linn GW et al., Annals of Internal Medicine 1983 (calorie balance study during purges of 4 to 6 liters) (checked on October 7, 2026)

    Senna is a real medicine for occasional constipation, sold over the counter. NIH’s MedlinePlus advises not taking it for more than one week without talking to your doctor, warns that frequent or continued use may make you dependent on laxatives so that your bowels “lose their normal activity”, and notes it can cause cramps, nausea and faintness. Rectal bleeding needs medical attention right away. A product you drink every evening for 14 or 28 days is a long course of a laxative, whatever the packaging calls it.

    Why the scale drops anyway

    Three things make a cleanse look as if it worked. First, the gut empties. Second, diuretic herbs and caffeine make you pass more urine for a few hours: in a small 2009 study, a dandelion leaf extract increased how often 17 volunteers urinated in the five hours after the first dose. Third, cleanses are usually very low in calories and carbohydrates, so the body uses its glycogen (stored carbohydrate). Glycogen is stored with three to four parts water, so using it up releases a lot of water weight in the first days of any very low-calorie plan, and eating normally again brings it straight back.

    Evidence that detox teas or cleanses cause lasting fat lossNone found

    Juice cleanses and colon cleansing

    Juice cleanses replace meals with juices for a few days. They do cut calories, but NCCIH points out several risks: unpasteurized juices can carry harmful bacteria, which is especially serious for children, older adults and people with weak immune systems; juices made from high-oxalate foods such as spinach and beets can be a problem for people prone to kidney stones; and the laxative products often sold alongside them can cause diarrhea, dehydration and poor absorption of nutrients. Very low-calorie cleanses also leave little room for protein, which you need to protect muscle.

    Colon cleansing (colonic irrigation) has little evidence behind it, and NCCIH lists potentially serious side effects, especially for people with digestive disease, past colon surgery, severe hemorrhoids, kidney disease or heart disease. If you feel bloated or irregular, our guide to a flatter stomach covers common causes of bloating and when it is worth seeing a doctor.

    What regulators have done

    The FTC and Teami (2020). In March 2020, the Federal Trade Commission announced a settlement with Teami, LLC and its owners. The FTC alleged that they claimed, without reliable scientific evidence, that the Teami 30 Day Detox Pack would help people lose weight and that other teas could fight cancer, clear clogged arteries and treat colds and flu. The complaint also highlighted paid Instagram posts by well-known influencers whose disclosure was hidden unless followers clicked “more”. The order banned unsupported health claims, required clear disclosure of paid endorsements and imposed a $15.2 million judgment, suspended on payment of $1 million because of the defendants’ inability to pay. The FTC also sent warning letters to 10 influencers.

    The FTC's Teami case, March 2020

    Checked on October 7, 2026

    The FDA and tainted “slim” teas. The FDA tests products sold for weight loss and posts public notifications when it finds hidden drugs. Two examples from its tainted-products list: in 2014 the agency warned that Lingzhi Cleansed Slim Tea contained sibutramine, and in 2021 it warned that Vy & Tea contained sibutramine. Sibutramine is a prescription weight-loss drug that was removed from the U.S. market in October 2010 for safety reasons; the FDA warns it can substantially raise blood pressure and pulse and is especially risky for people with heart disease or a history of stroke. Other products have contained phenolphthalein, a laxative chemical that is not an approved drug ingredient in the United States and that studies suggest may raise cancer risk.

    These are not rare accidents. A 2018 analysis of the FDA’s tainted-supplements database found 776 adulterated products between 2007 and 2016, and 317 of them were sold for weight loss. Among those weight-loss products, 84.9% contained sibutramine. The FDA itself says its list covers only a small fraction of the contaminated products on the market, so a product’s absence from the list is not proof that it is clean.

    Adulterated supplements found by the FDA, 2007 to 2016, by what they were sold for
    Adulterated supplements found by the FDA, 2007 to 2016, by what they were sold for
    ItemValue
    Sexual enhancement353
    Weight loss317
    Muscle building92

    776 products in all; sibutramine was in 84.9% of the weight-loss products.

    Source: Tucker J et al., JAMA Network Open 2018 (analysis of the FDA tainted-products database) (checked on October 7, 2026)

    How to spot a risky detox product

    • Fast-loss promises. “Lose 10 pounds in 7 days” or “flatten your belly overnight” are classic warning signs in FTC and FDA consumer advice.
    • Senna or another laxative in a daily, multi-week program. Check the label, including “evening” or “colon” teas.
    • Disease claims. A tea that claims to fight cancer or clear arteries is making claims the FTC said Teami could not back up.
    • Influencer posts with buried disclosures. Paid posts must say so clearly; the FTC’s case turned on posts that hid it.
    • Imported “slimming” teas sold online with labels you can’t read. Several FDA notices involve products like these. Our guide on how to read a supplement label shows what else to check.

    What to do instead

    If you want the “fresh start” feeling a cleanse promises, you can get it in ways that also help long term. Drink water and unsweetened tea in place of sugary drinks (see our weight-loss drinks list). Fill up on vegetables, fruit, beans and whole grains, which add fiber that keeps you regular without a laxative; our best filling foods and the fibermaxxing explainer help. And aim for a modest, steady calorie deficit. If you want results quickly but safely, our page on losing weight fast explains what is realistic.

    The verdict

    Detox teas and cleanses do not remove fat. They move water and stool, and the quick drop on the scale comes back. Some contain laxatives meant for short-term use, a few have contained hidden prescription drugs, and the best-known detox tea brand settled FTC charges over its claims. Your money is better spent on food and habits that last. For more claims checked against the evidence, see our weight-loss myths roundup, our supplements hub, the history of diet fads and our look at weight-loss hoaxes in history.

  • How to Get a Flatter Stomach: What Works and What Doesn’t

    How to Get a Flatter Stomach: What Works and What Doesn’t

    In short: How flat your stomach looks depends on four things: the fat under the skin and around the organs, bloating from gas and digestion, posture, and the strength of your core muscles. Fat comes down only with overall fat loss, from a steady calorie deficit and regular aerobic exercise; crunches alone don’t remove it. Bloating often responds to eating more slowly, fewer fizzy drinks and a closer look at trigger foods. Strength and posture work makes your middle firmer and taller, and shapewear can smooth the outline for an occasion.

    If your main goal is losing fat around your middle, our full guide on how to lose belly fat has the detailed plan, and our page on visceral fat explains the health side. This page is about the everyday question “how do I get a flatter stomach?”, which is broader: a stomach can look rounder on Friday evening than on Monday morning without any change in fat. Below, we take the four factors one at a time and show what the research supports for each.

    The four things that shape how your stomach looks

    1. FatFat under the skin and visceral fat around the organs. Changes over weeks with overall fat loss.
    2. BloatingGas, constipation and swallowed air. Changes within hours or days.
    3. PostureHow you stand and hold your ribs and pelvis. Changes in seconds.
    4. Muscle toneCore strength and endurance. Changes over weeks of training.

    1. Fat: the part that needs overall fat loss

    There are two kinds of belly fat. Subcutaneous fat sits under the skin and is the part you can pinch. Visceral fat lies deeper, around the liver and intestines, and pushes the belly out from inside; it is the type most linked with heart disease and type 2 diabetes. Both come down when your body fat comes down overall, and neither can be targeted with one exercise. In a six-week trial, adults who did seven ab exercises five days a week got much better at curl-ups but saw no change in belly fat or waist size. Our spot reduction explainer covers the full evidence.

    Six weeks of daily ab exercises: stronger, not slimmer
    Six weeks of daily ab exercises: stronger, not slimmer
    ItemValue
    Curl-ups, ab exercise group47
    Curl-ups, control group32

    Curl-up repetitions at the end of the trial. There was no significant change in belly fat, body fat percentage or waist circumference.

    Source: Vispute SS et al., Journal of Strength and Conditioning Research 2011 (24 adults, 6 weeks) (checked on October 7, 2026)

    What does work for fat around the middle:

    • Aerobic exercise. A meta-analysis of 35 trials that measured visceral fat by CT or MRI found that aerobic exercise reduced it compared with no exercise, while resistance training alone did not show a significant effect. Even amounts below the usual weight-loss recommendations may help. Brisk walking counts.
    • A steady calorie deficit. Choose an eating pattern you can keep up; our calorie deficit guide shows how to set one.
    • Enough sleep. In a 2022 inpatient study, two weeks of 4-hour nights with free access to food made people eat more and gain weight, and fat inside the abdomen increased, both under the skin and around the organs. Another 2022 trial found that adults who usually slept less than 6.5 hours and extended their sleep by about 1.2 hours a night ate about 270 fewer calories a day.

    Waist numbers worth knowing

    • 35 in / 40 inwaist sizes above which health risk rises for women / men, measured just above the hip bones after breathing outNHLBI (NIH)
    • Under halfa waist below half your height is the healthy range in UK NICE guidance (waist-to-height ratio under 0.5)NICE NG246
    • 270 kcalless eaten per day after sleep was extended by about 1.2 hours a nightTasali E et al., JAMA Internal Medicine 2022

    Checked on October 7, 2026

    2. Bloating: the part that changes by the hour

    Many people who feel their stomach “isn’t flat” are describing bloating: a sense of fullness or pressure, sometimes with visible swelling that builds through the day. Common causes are swallowed air, gas made when gut bacteria ferment certain carbohydrates, and constipation. The National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK) lists foods and drinks that often cause gas, and simple habits that help:

    • Eat slowly, ideally sitting down, and avoid talking while you chew, to swallow less air.
    • Cut back on chewing gum, hard candy, fizzy drinks and drinking through a straw, which all add air.
    • Try smaller, more frequent meals instead of large ones.
    • Notice common gas triggers: beans and lentils; broccoli, cauliflower and other cruciferous vegetables; apples, pears and fruit juice; milk products for people with lactose intolerance; drinks with high-fructose corn syrup; and sugar alcohols such as sorbitol, xylitol, erythritol and maltitol found in “sugar-free” foods.

    Many of these foods are healthy and filling, so the goal is not to cut them all. Raise fiber gradually and drink enough water, as our fibermaxxing explainer describes, and keep a short food-and-symptom note for two weeks to find your own triggers. The American Gastroenterological Association’s 2023 expert review on bloating advises that when a restrictive plan such as a low-FODMAP diet is needed, a gastroenterology dietitian should preferably guide it, and that probiotics should not be used to treat bloating and distention.

    Interestingly, visible belly swelling is not always about how much gas is inside. A 2011 study found that in many people with bloating, the diaphragm moves down and the front belly wall relaxes, pushing the belly out. The AGA review lists diaphragmatic breathing as a treatment for this pattern. Detox teas and laxative “flat tummy” products are not the answer; our page on detox teas and cleanses explains why.

    3. Posture: the part you can change right now

    Stand sideways to a mirror and let your shoulders round and your pelvis tip forward, then stand tall with your ribs stacked over your hips. The difference in how your stomach looks can be striking, with no change in the body itself. Plastic surgeons point out the same effect in photos: an article from the American Society of Plastic Surgeons describes the flanks looking full with arms down and slimmer with arms raised. You don’t need to hold your breath or suck in all day; gentle cues such as “tall through the crown of the head” and “ribs down” are enough, and a stronger back and core make them easier to keep.

    4. Muscle tone: the part that makes the middle firmer

    Core training won’t remove fat, but it does build strength and endurance in the muscles that wrap around your middle. That makes the area feel firmer and makes a tall posture easier to hold. A balanced routine trains the whole trunk, front, sides and back, rather than doing only crunches:

    • Anti-extension: planks, dead bugs.
    • Anti-rotation and side work: side planks, suitcase carries, pallof presses with a band.
    • Back and hips: bird-dogs, glute bridges, hip hinges.

    Fold these into two or more full-body strength sessions a week, the amount the Physical Activity Guidelines suggest; our strength training guide and best home workouts list have routines. Strength work also helps protect muscle while you lose weight: a 2021 overview of reviews found resistance training reduced lean-mass loss by about 0.8 kg.

    Other things that change your middle

    Menopause. Many women notice their shape changing in midlife. A 2012 review in Climacteric explains that while weight gain itself can’t be blamed on the menopause transition, the hormonal change at menopause is linked with more total body fat and more fat around the abdomen. The same habits help, with extra attention to strength training and protein, and it is worth discussing symptoms and options with your clinician.

    Alcohol. The National Institute on Alcohol Abuse and Alcoholism notes that alcoholic drinks supply calories but few nutrients and may contribute to unwanted weight gain. Its free alcohol calorie calculator shows how quickly a few drinks a week add up, and cutting back is often one of the simplest changes to make.

    Constipation. A backed-up bowel can make the belly feel full and look rounder. The AGA review suggests that when bloating comes with constipation, treating the constipation should be considered, and that a pelvic floor problem may be the cause when emptying is difficult. Fiber from food, fluids and daily movement are the usual first steps; a clinician can help if it lasts.

    What doesn’t work

    • Hundreds of crunches a day to “burn” belly fat. They build endurance, not fat loss.
    • Sweat belts and waist trainers worn to slim the waist permanently. They hold you in while you wear them; see our waist trainer guide.
    • Detox teas and “flat tummy” laxatives. They move water and stool, which come back.
    • “Belly fat burner” pills. None has good evidence; our fat burners page explains the risks.

    Shapewear, and when the issue is skin

    For an event or simply for comfort, tummy-control shapewear can smooth the outline under clothes. It does not change fat or muscle, and it should never feel painful or restrict breathing. Our shapewear guide explains fit and comfort, and the best tummy-control shapewear list compares options. After a big weight loss or pregnancy, a stomach that won’t flatten may be partly loose skin rather than fat. Our loose skin guide and the page on tummy tucks cover that, and our non-surgical tummy tuck explainer checks the claims of “no-surgery” options. Body contouring is not weight loss.

    A four-week plan for a flatter stomach

    Do these next, 1-2-3-4

    1. Measure once, then waitMeasure your waist just above the hip bones after breathing out, at the same time of day. Re-measure in 4 weeks, not daily.
    2. Move most daysBuild toward 150 to 300 minutes of brisk walking or other aerobic activity a week.
    3. Train your core twice a weekPlanks, side planks, bird-dogs and carries inside two full-body strength sessions.
    4. Calm the bloatEat slowly, cut fizzy drinks and gum, and keep a two-week food-and-symptom note.
    5. Protect your sleepAim for 7 hours or more, which the CDC recommends for adults.

    Track how your clothes fit, your energy and your strength as well as your waist; our guide to tracking progress without the scale lists more measures. And remember that a stomach that is soft, rounded or changes through the day is normal. The goal is a healthier middle and feeling good in your body, not a perfectly flat line.

  • How to Read a Supplement Label (and Spot Red Flags)

    How to Read a Supplement Label (and Spot Red Flags)

    In short: Start with the Supplement Facts panel: check the serving size, the amount of each ingredient, and whether key ingredients hide inside a “proprietary blend” that shows only a total weight. Then read the claims: “supports metabolism” is a legal structure/function claim that the FDA has not evaluated, while a claim to treat a disease is not allowed on a supplement. Look for an independent quality seal such as USP, NSF or ConsumerLab, which checks contents but not whether the product works. Treat fast weight-loss promises and “drug-like” effects as red flags: the FDA has found hidden prescription drugs in hundreds of weight-loss supplements.

    Weight-loss supplements are a crowded shelf, and labels are written to sell. This guide walks through every part of a U.S. supplement label, what the law requires on it, and the warning signs regulators look for. For what the evidence says about specific ingredients, see our supplements hub and the broader weight-loss pills guide. It is general education, not advice about any product: check with a pharmacist or clinician before taking a supplement, especially with prescription medicines.

    First, what “dietary supplement” means legally

    Under the 1994 Dietary Supplement Health and Education Act (DSHEA), supplements are regulated as a kind of food, not as drugs. The FDA states that it does not have the authority to approve dietary supplements before they are marketed; companies are responsible for making sure their products are safe and their labels truthful. The NIH Office of Dietary Supplements (ODS) puts the contrast simply: medicines must be approved by the FDA before they can be sold, supplements do not. So the label is the main information you get, and knowing how to read it matters.

    Supplement facts most people don't know

    Checked on October 7, 2026

    The Supplement Facts panel, annotated

    Below is a made-up example label for a typical “metabolism” capsule, followed by what each numbered part tells you. It is not a real product.

    Supplement Facts (example only)

    ① Serving Size 2 capsules · Servings Per Container 30
    Amount Per Serving② % Daily Value
    Vitamin B12 (as cyanocobalamin) 6 mcg250%
    Chromium (as chromium picolinate) 200 mcg571%
    ③ Thermo Metabolic Blend 850 mg
    Green tea (leaf) extract, Garcinia cambogia (fruit) extract, Caffeine anhydrous, Capsicum (fruit) extract, Black pepper (fruit) extract
    †
    † Daily Value not established
    ④ Other ingredients: gelatin capsule, rice flour, magnesium stearate
    ⑤ “Supports a healthy metabolism*” · *This statement has not been evaluated by the Food and Drug Administration…
    ⑥ Seal: none · Manufacturer name and U.S. address or phone
    1. Serving size. Federal rules require “Serving Size” right under the “Supplement Facts” heading. Every amount on the label is per serving, so if a serving is two or three capsules, a bottle may last half as long as you think, and the dose in one capsule is a fraction of what is listed. The ODS notes that the maker suggests the serving size, but your health care provider might decide a different amount is right for you.
    2. % Daily Value. Vitamins and minerals with established daily values show a percentage. Ingredients without one, such as most herbs and caffeine, carry a symbol pointing to “Daily Value not established”. Very high percentages are not a sign of a better product, and more is not always safer.
    3. Proprietary blend. A blend may be listed under a trademark-style name with only the total weight of its ingredients. The rule requires the ingredients to be listed in descending order of weight, but not the amount of each. In the example, you can’t tell whether the 850 mg is mostly caffeine or mostly pepper extract, or whether any ingredient is present in the amount used in studies. For caffeine, that matters: the FDA cites 400 mg a day as an amount not generally associated with negative effects for most adults.
    4. Plant parts and other ingredients. Botanical ingredients must name the part of the plant used (leaf, root, fruit), which matters because parts can differ. “Other ingredients” lists fillers, binders, capsules and flavors; check it for allergens and, if you avoid animal products, gelatin.
    5. Claims and the disclaimer. Phrases like “supports metabolism” or “helps maintain healthy weight” are structure/function claims. They must carry the FDA disclaimer that begins “This statement has not been evaluated by the Food and Drug Administration”, and the company must notify the FDA within 30 days of first marketing them. That notice is not an approval.
    6. Who made it, and any seal. Look for the company’s name and a U.S. address or phone number so you can ask questions or report a problem, plus any independent quality seal (see below).

    Structure/function claims vs disease claims

    This is the single most useful distinction on the label. Under 21 CFR 101.93, a supplement may describe how an ingredient affects the normal structure or function of the body, but it may not claim to diagnose, treat, mitigate or prevent a disease; a product that makes a disease claim is regulated as a drug. The FDA’s definition is broad: a claim can be a disease claim through the product name, pictures or symbols, or by saying the product is a substitute for a disease therapy or works like a particular drug.

    Wording you might seeWhat kind of claimWhat to think
    “Supports a healthy metabolism”Structure/functionLegal with the disclaimer; not FDA-evaluated, so look for human trials
    “Helps curb cravings”Structure/functionSame: ask for the evidence
    “Treats obesity” or “lowers blood sugar in diabetes”Disease claimNot allowed on a supplement; a red flag
    “Works like Ozempic” or “a natural GLP-1”Implies it substitutes for a drug therapyA red flag; see our “nature’s Ozempic” explainer
    “Lose 30 pounds in 30 days”Fast-loss promiseThe FTC lists this kind of promise among claims that are always false

    Quality seals: what they check, and what they don’t

    Because the FDA doesn’t test supplements before sale, some companies pay independent organizations to test them. The ODS names three that offer quality testing: ConsumerLab.com, NSF International and U.S. Pharmacopeia (USP). A seal indicates the product was properly manufactured, contains the ingredients listed on the label and does not contain harmful levels of contaminants. USP describes its Verified Mark as covering identity, strength, purity and how well a tablet breaks down, and NSF’s certification includes a label-claim review and testing for contaminants and undeclared ingredients; its Certified for Sport program also screens for substances banned in sport.

    What a seal does not do: the ODS stresses that these seals do not mean a product is safe or effective. A perfectly made capsule of an ingredient with weak evidence is still an ingredient with weak evidence. Use a seal to answer “is what’s on the label in the bottle?”, and the research to answer “does it work?” Our pages on fat burners, green tea extract, berberine and fiber supplements rate the evidence for common ingredients.

    Red flags for hidden drugs

    Weight-loss products are one of the categories most often found with hidden prescription drugs. A 2018 analysis of the FDA’s tainted-products database found 776 adulterated supplements from 2007 to 2016; 317 were sold for weight loss, and 84.9% of those contained sibutramine, a prescription diet drug withdrawn in 2010 because of heart attack and stroke risk. Other hidden ingredients have included the laxative chemical phenolphthalein and the antidepressant fluoxetine. Recalls don’t always fix the problem: when researchers bought 27 recalled supplements an average of 34 months after their FDA recall, 18 of them, two thirds, still contained a banned drug.

    Recalled supplements still on sale years later: what testing found
    Recalled supplements still on sale years later: what testing found
    ItemValue
    Still contained a banned drug18
    No banned drug found9

    18 of 27 (66.7%) contained one or more pharmaceutical adulterants, including sibutramine and its analogs, phenolphthalein and fluoxetine.

    Source: Cohen PA et al., JAMA 2014 (27 recalled supplements bought a mean of 34 months after FDA recall) (checked on October 7, 2026)

    The FDA’s “6 tip-offs to rip-offs” give the warning signs to watch for:

    • One product does it all, treating a long list of unrelated problems.
    • Personal testimonials in place of scientific evidence; success stories are easy to make up.
    • Quick fixes such as “lose 30 pounds in 30 days”.
    • “All natural” used as proof of safety.
    • Words like “new discovery”, “secret ingredient” or promises of sure results.
    • Conspiracy claims that doctors or the government don’t want you to know.

    Where the tainted products came from is telling too: in 2014 to 2016, 38.6% of the adulterated samples in the 2018 analysis were found through online sampling and 34.3% in international mail shipments. So be extra careful with products sold only online, shipped from abroad or labeled in a language you can’t read, and with any product whose effects feel like a strong drug. Before buying, search the product name in the FDA’s tainted-products notifications (our detox tea page explains how they work), but remember the FDA says its list covers only a small fraction of contaminated products.

    Check for interactions

    “Natural” does not mean it can’t interact with medicines. The ODS gives examples: vitamin K can reduce how well the blood thinner warfarin works, and St. John’s wort can speed the breakdown of many medicines, including some antidepressants, birth control pills and heart medicines, making them less effective. Berberine, a popular “metabolism” ingredient, can change levels of some prescription drugs; our berberine page has details. Bring the bottle, not just the name, to your pharmacist.

    A 60-second label check

    Before you buy any weight-loss supplement

    1. Find the serving sizeWork out the amount per capsule and per day.
    2. Look for blendsIf key ingredients hide in a "proprietary blend", you can't know the dose.
    3. Read the claimsStructure/function with the disclaimer is legal; disease or drug-like claims are red flags.
    4. Check for a sealUSP, NSF or ConsumerLab means quality-tested contents, not proof it works.
    5. Ask about interactionsShow the bottle to your pharmacist, especially if you take prescriptions.

    The bottom line

    A supplement label tells you what the maker says is inside, not whether it works. Read the serving size and amounts, be wary of proprietary blends, know the difference between a structure/function claim and a disease claim, and use quality seals for what they are. If a product promises fast or drug-like weight loss, walk away. For proven options, our lose weight hub covers food and activity, and our guide to choosing a weight-loss program helps you find support. To see every kind of option side by side, try our Find My Options tool, and talk with your clinician about what fits you.

  • How to Track Progress Without the Scale: 8 Measures That Matter

    How to Track Progress Without the Scale: 8 Measures That Matter

    In short: The scale is only one number, and it swings with water, food and hormones from day to day. Eight other measures show progress more fully: your waist, your waist-to-height ratio, how clothes fit, consistent progress photos, strength and fitness, energy, sleep and mood, health numbers such as blood pressure and blood sugar, and how consistently you keep your habits. Pick three or four, check them every two to four weeks, and use the printable sheet below.

    An interracial couple exercising together at home in a bright, modern living room.
    Photo: SHVETS production / Pexels

    People call these “non-scale victories”, and they matter. In trials, modest weight loss of 5 to 10% already improves blood sugar and blood pressure, and strength training can change your shape while the scale barely moves. This page explains each measure, how to take it the same way every time, and what research says it tells you. If you are keeping weight off after a loss, our maintenance guide covers the other side; there, weighing in regularly is one of the best-supported habits, so these measures add to the scale rather than replace it for most people.

    Why the scale alone can mislead you

    Body weight moves for reasons that have nothing to do with fat. A European study that followed more than 1,400 adults on connected scales found weight typically rose at weekends and fell on weekdays by about 0.35%, and climbed about 1.35% over Christmas. Stored carbohydrate (glycogen) is held with three to four parts water, so a carb-heavy day can add water weight overnight. And when you start strength training, you may gain a little muscle while losing fat, so the scale can stall even as your body changes. Looking at several measures smooths out that noise.

    Why one number isn't enough

    Checked on October 7, 2026

    The 8 measures

    1. Waist circumference

    Your waist tracks the fat around your middle, the kind most linked with heart disease and type 2 diabetes. The NIH’s National Heart, Lung, and Blood Institute explains how to measure it: stand, place a tape measure around your middle just above your hip bones, and measure just after you breathe out. Risk rises above 35 inches for women and 40 inches for men. Measure at the same time of day, ideally in the morning, every two to four weeks. Our guide to losing belly fat explains what moves this number.

    2. Waist-to-height ratio

    Divide your waist by your height, in the same units. A 2012 meta-analysis of studies including more than 300,000 adults found that this ratio picked out people with high blood pressure, type 2 diabetes and heart risk better than waist alone or BMI, in men and women and across ethnic groups. UK NICE guidance uses a simple target: keep your waist to less than half your height (a ratio under 0.5). It is a useful companion to the BMI calculator, because BMI doesn’t show where fat is carried.

    3. How your clothes fit

    Choose one “test” item, such as a pair of jeans or a fitted shirt, and try it on every few weeks. Note which button hole the belt uses, or how the waistband feels when you sit down. It is low-tech, free and surprisingly sensitive, and it reflects the changes in shape that matter to most people day to day.

    4. Progress photos, taken fairly

    Photos can show changes you miss in the mirror, but only if you take them the same way each time: same place, same light, same time of day, same clothes, same pose, same camera distance. Lighting and posture alone can make a big difference, as our explainer on before-and-after photos shows. Take them every four weeks and keep them private unless you want to share.

    5. Strength and fitness

    Performance is one of the most motivating measures. The American Council on Exercise (ACE) suggests coaches track “strength, endurance and movement quality” alongside body measures. Simple tests: how many push-ups (on the floor or against a counter) or sit-to-stands from a chair you can do with good form, the weight you lift for 10 reps, or how long a familiar walking route takes. Strength training also protects muscle while you lose weight: a 2021 overview found it reduced lean-mass loss by about 0.8 kg. Our strength training guide and body recomposition page explain why the scale can stay still while you get leaner and stronger.

    6. Energy, sleep and mood

    ACE lists recovery markers such as “sleep, energy, soreness, mood and daily function” as progress indicators, and suggests simple questions: do you feel rested when you wake, how is your energy through the day, how stressed do you feel on a scale of 1 to 10? Rate each from 1 to 5 once a week, and note your average hours of sleep; the CDC recommends 7 or more hours a night for adults, and a wearable or a simple bedtime log can show whether you are getting there. These often improve before the scale moves, and they are often the changes people value most: climbing stairs without stopping, playing with kids, sleeping better.

    7. Health numbers

    Blood pressure, blood sugar (HbA1c) and blood fats respond to even modest weight loss. In the Look AHEAD study of 5,145 adults with type 2 diabetes, people who lost 5 to under 10% of their weight in a year had about 3.5 times the odds of a meaningful drop in HbA1c and about 1.5 times the odds of a 5-point drop in blood pressure, compared with people whose weight stayed stable. The CDC notes that a 5% loss (10 pounds for a 200-pound person) can lower the risk of some chronic diseases. Ask your clinician which numbers to track and how often; a home blood pressure monitor can help if you have high blood pressure.

    Losing 5 to under 10% of body weight in a year: odds of meaningful health improvements vs stable weightValues in x
    Losing 5 to under 10% of body weight in a year: odds of meaningful health improvements vs stable weight
    ItemValue
    HbA1c down 0.5 points3.52 x
    Systolic blood pressure down 5 mmHg1.56 x
    Diastolic blood pressure down 5 mmHg1.48 x

    Odds ratios compared with weight-stable participants; 1 would mean no difference.

    Source: Wing RR et al., Diabetes Care 2011 (Look AHEAD, 5,145 adults with type 2 diabetes) (checked on October 7, 2026)

    8. Habit consistency

    The things you do are the measure you control most. A systematic review of 22 studies found a consistent link between self-monitoring (of food, activity or weight) and weight loss, and ACE notes that someone “training twice a week, walking regularly and eating with more structure has changed something meaningful, even if body weight has not moved”. Track two or three habits as simple ticks: walks done, strength sessions, vegetables at lunch, bedtime kept. Habits take time to become automatic: in one study the time ranged from 18 to 254 days, so streaks are worth celebrating. See our list of habits to slim down for ideas.

    Match the measures to your goal

    Your main goalMeasures that fit bestHow often
    Lose fat around the middleWaist, waist-to-height ratio, test outfitEvery 2 to 4 weeks
    Get stronger and fitterStrength test, walk time, energy scoreEvery 4 weeks
    Improve health markersBlood pressure, HbA1c, cholesterolAs your clinician advises
    Build lasting habitsHabit ticks, sleep, moodDaily ticks, weekly review
    Keep weight off after a lossRegular weigh-ins plus waist and habitsWeekly weigh-in, monthly review

    The scale still has a place

    Tracking without the scale doesn’t mean the scale is useless. For keeping weight off, regular weighing is one of the best-supported habits: in the STOP Regain trial, a program built on daily self-weighing cut the share of people who regained 5 pounds or more over 18 months from 72.4% to 45.7%. The trick is how you read it. Look at your weekly average or the trend over a month, not one morning’s number, and pair it with two or three of the measures above so a water-heavy day doesn’t undo a good month. If the scale causes you distress, it is fine to set it aside and lean on the other measures.

    Dancing, couple, home, joy, senior, love, music, retirement, living, room, happiness, marriage, activity, lifestyle, together, indoor, fun, aging, romance, movement, ai generated
    Photo: geralt / Pixabay

    What about body fat percentage?

    Body fat estimates are tempting, but home devices are better for spotting trends than for exact numbers. A study comparing consumer bioimpedance scales with MRI and DXA scans found that foot-to-foot scales were much less precise for individuals than devices with hand and foot electrodes. If you use one, weigh in under the same conditions and watch the direction over months. Our body fat calculator gives an estimate from tape measurements, and body fat measurement methods compared explains DXA, calipers and scales. For a connected scale, see our best smart scales; for steps and sleep, fitness trackers.

    How to set up your tracking

    A simple tracking routine

    1. Pick 3 or 4 measuresFor example waist, one test outfit, a strength test and a weekly energy score.
    2. Take a baselineSame morning, same conditions. Write the date.
    3. Track habits weeklyTick the two or three habits you are building, every day or week.
    4. Re-measure every 2 to 4 weeksBody measures change slowly; checking daily adds noise and worry.
    5. Review the trendLook at the direction over a month or two, then adjust one habit at a time.

    Printable tracking sheet

    Print this page or copy the sheet into your phone’s notes. Fill in a baseline, then one column every four weeks.

    My progress, beyond the scale

    MeasureStart (date: ____)Week 4Week 8Week 12
    Waist (inches), above hip bones, after breathing out
    Waist ÷ height (aim under 0.5)
    Test outfit: how it fits (1 tight to 5 loose)
    Photo taken? (same place, light, pose)☐☐☐☐
    Strength: push-ups or sit-to-stands
    Fitness: time for my usual walk
    Energy, sleep, mood (each 1 to 5)
    Health numbers (blood pressure, other)
    Habits kept this month (out of 4 weeks)

    From instatuck.com, checked against NHLBI, NICE, ACE and published studies on October 7, 2026. Education only; not medical advice.

    When to step away from tracking

    Tracking should feel useful, not punishing. If measuring, photographing or weighing leaves you anxious, guilty or checking compulsively, take a break and focus on how you feel and what you can do. Our page on body image has support, and a clinician or an eating disorder specialist can help if tracking has started to control your days. Progress is more than a number, and many of the most important wins, like better sleep, more energy and steadier blood sugar, never show up on a scale at all. For the habits that keep results going, see our habits of people who keep weight off.

  • Weight-Loss Before-and-After Photos: What’s Real, Edited and Typical

    Weight-Loss Before-and-After Photos: What’s Real, Edited and Typical

    In short: Many before-and-after photos show a real change, but the gap is often widened by lighting, posture, clothing, timing and editing, and the people chosen are usually the best results, not the typical ones. U.S. rules agree: under the FTC’s Endorsement Guides, an ad that shows one person’s dramatic loss is taken to promise similar results to you, and a small “results not typical” note does not fix that. In trials, the typical extra loss from popular commercial programs was a few percent of body weight over a year.

    High angle of cheerful ethnic female friends wearing Santa hats laughing together while sharing mobile phone
    Photo: Julia Larson / Pexels

    This page explains how to read the photos you see in ads and on social media: what can make a picture look different without any change in the body, what the law says advertisers must show, and what results are realistic. It is also why InstaTuck never uses before-and-after photos, as our editorial standards explain. If you are looking for honest numbers on speed, see our guide to losing weight fast, and for body confidence, our body hub.

    Why the photos are so persuasive

    A pair of photos tells a story in a second: one person, one product, one dramatic change. Our eyes read the “after” as the result of the product and assume we would get the same. That is exactly how the Federal Trade Commission says consumers read such ads. Its Endorsement Guides state that an ad featuring a consumer’s experience on a key feature “will likely be interpreted as representing that the endorser’s experience is representative of what consumers will generally achieve”. The guides even use a weight-loss example: plain before-and-after pictures of a woman who says she lost 50 pounds in six months are likely to be read as a typical result.

    What can change between two photos (without changing the body)

    Think of this as an annotated example. Picture two photos of the same person taken an hour apart, with no weight change at all. Each of these can make the second photo look slimmer or more toned:

    What changes“Before” photo“After” photoWhy it matters
    LightingFlat, overhead or harsh lightSide light that creates shadows and contoursASPS warns that lighting and angles can change how results look
    Posture and poseSlouched, belly relaxed, arms downStanding tall, core braced, arms liftedA plastic surgeon quoted by ASPS describes flanks looking full with arms down and slimmer with arms up
    Camera angle and distanceClose up, lens at waist heightFurther back, slightly aboveDistance and angle change body proportions in a picture
    ClothingBaggy clothes or ill-fitting underwearFitted, dark or high-waisted clothingClothes change the outline a lot
    TimingAfter a salty meal or in the eveningMorning, after a workout, tannedWater and gut contents shift from day to day (see below)
    Editing and filtersUneditedSmoothed, reshaped or swappedThe FTC warns some ads use stock or altered photos, not product users

    Plastic surgeons have known this for years. The American Society of Plastic Surgeons’ Code of Ethics (updated January 2025) bars members from advertising with before-and-after photos “which use different light, poses, or photographic techniques to misrepresent the results achieved”, and from showing results that are not typical of the average patient without clearly saying so. An ASPS article for patients adds that “everyone puts their best before and after pictures forward” and that there are no industry-wide standards for how such photos are presented.

    Water weight: the hidden “before” and “after”

    Body weight moves around even when body fat does not. In a European study that tracked more than 1,400 people with connected scales, weight rose at weekends and fell on weekdays by about 0.35% on average, and rose about 1.35% over Christmas. Rapid early drops on low-carbohydrate or very low-calorie plans are partly water too: glycogen, the body’s stored carbohydrate, is held with three to four parts water, so using it up sheds water quickly. A “two-week transformation” photo can capture these swings rather than fat loss.

    Normal weight swings that photos can capture

    Checked on October 7, 2026

    What the FTC requires

    The FTC’s Guides Concerning the Use of Endorsements and Testimonials in Advertising (16 CFR Part 255, last amended in July 2023) set out the rules most relevant to before-and-after ads:

    • Testimonials are not evidence. An advertiser needs the same scientific support for a claim made through a customer story as for a claim it makes directly. “Consumer endorsements themselves are not competent and reliable scientific evidence.”
    • Typical results must be shown. If a featured person’s results are not what people generally achieve, the ad should clearly disclose the generally expected results. The guides’ example of a good disclosure is “women who use QRS Weight-Loss for six months typically lose 15 pounds”.
    • “Results not typical” is not enough. The FTC tested that wording, and the stronger “you are not likely to have similar results”, and found neither stopped viewers from assuming the results were typical.
    • Real people, real pictures. Ads that present “actual consumers” should use actual consumers or say they don’t. The guides give an example of a deceptive ad that pairs a real 50-pound loss with a photo of someone much thinner than the real endorser.
    • Paid connections must be disclosed. Free products, payments and family or business ties to the brand must be clear.

    The FTC’s 2022 Health Products Compliance Guidance adds that health claims generally need support from high-quality randomized controlled trials in people, which a photo can never provide. Since October 21, 2024, a separate FTC rule also bans fake reviews and testimonials, including buying them or having company insiders write them without disclosure. And the FTC enforces these rules in weight loss: in 2025 it finalized an order against the telehealth provider NextMed, which it charged with unsupported weight-loss claims, fake testimonials and distorted consumer reviews. The FTC’s consumer advice puts it simply: some dramatic images “are just stock or altered photographs, not photos of people who actually used the product.”

    What typical results look like

    Honest numbers are less dramatic and more encouraging than they sound. A 2015 review in the Annals of Internal Medicine pooled randomized trials of commercial programs. At 12 months, Weight Watchers (now WW) participants lost at least 2.6% more of their weight than people given education alone, and Jenny Craig participants at least 4.9% more. For a 200-pound person, that is roughly 5 to 10 pounds beyond what a control group lost, and the CDC notes that a 5% loss can already lower the risk of some chronic diseases. Prescription medicines can lead to larger average losses; our FDA-approved medications compared page gives the trial numbers.

    Extra weight lost at 12 months vs control groups in commercial-program trialsValues in %
    Extra weight lost at 12 months vs control groups in commercial-program trials
    ItemValue
    Jenny Craig (vs control/education)4.9%
    Weight Watchers (vs control/education)2.6%

    Values are "at least" differences in percent of body weight, from randomized trials. Typical results, not best cases.

    Source: Gudzune KA et al., Annals of Internal Medicine 2015 (systematic review of 45 studies) (checked on October 7, 2026)

    The CDC also notes that people who lose weight gradually, about 1 to 2 pounds a week, are more likely to keep it off. Our best weight-loss programs list and the guide on how to choose a weight-loss program show how to ask a program for its average results rather than its best photos.

    Smiling woman enjoys a sunny walk with her dog in a lush green park.
    Photo: Helena Lopes / Pexels

    How to read any before-and-after ad

    Five questions to ask about a transformation photo

    1. Same conditions?Check light, pose, clothing, camera distance and time of day. If they all changed, the photo proves little.
    2. How long, and how?Look for the time frame and everything the person did, such as diet, exercise, medicine or surgery.
    3. Is it typical?Look for the average result in the ad. A tiny "results not typical" line is a warning sign, not a disclosure.
    4. Is it a real user?Stock images, reused photos and paid endorsers must be disclosed; reverse image search helps.
    5. What do the studies say?Ask for trial results for the product or program, not testimonials.

    Why it matters for how you feel

    Idealized photos don’t only sell products; they can also change how people feel about their own bodies. In a 2020 experiment, researchers showed 192 young women Instagram images of thin, attractive women. Seeing the images with a “reality check” comment underneath, one that pointed out the photo was not realistic, reduced body dissatisfaction compared with seeing the same images with a flattering comment alone. In other words, reminding yourself how photos are made is not cynicism; it is a simple way to protect your confidence while you work on your health. Unfollowing accounts that make you feel worse is another.

    Before-and-after photos for surgery and contouring

    Photos matter more when you are choosing a surgeon or a body-contouring treatment, because you are judging someone’s skill. Ask to see many photos of patients with a starting point like yours, taken in the same position and light, and ask how many months after treatment they were taken. Our checklist of questions before body contouring and the guide to finding board-certified plastic surgeons help. Remember that body contouring reshapes an area; it is not weight loss.

    Your own photos: useful, if you keep them fair

    Progress photos can be a helpful private record, as long as you take them the same way each time: same spot, light, time of day, clothing and pose. Take them every four weeks rather than daily, because daily water swings will mislead you. Photos work best next to other measures, such as your waist, how clothes fit, strength and energy; our guide to tracking progress without the scale lists eight. And if comparing your body to others’ photos leaves you feeling worse, step back: our page on body image has support and ideas.

    The verdict

    Before-and-after photos are real moments, carefully chosen and often staged. Lighting, pose, timing and editing can add a lot, and the people shown are rarely typical. U.S. law says a dramatic testimonial implies typical results, so ads must show what people generally achieve; when they don’t, that is your cue to look for the study instead of the picture. Typical, lasting results are smaller, slower and still worth a great deal for your health. For more claims checked against the research, see our spot reduction explainer and the weight-loss myths roundup.

  • Metabolism-Boosting Foods: Fact or Fiction?

    Metabolism-Boosting Foods: Fact or Fiction?

    In short: A few foods and drinks nudge your metabolism up, but only a little. Chili’s capsaicin added about 59 calories a day in pooled studies, caffeine and green tea extracts about 100 in lab conditions, and cold water roughly 24 calories per half liter at best. Compared with a typical day’s energy use of around 2,000 calories or more, those are rounding errors. What helps more is eating enough protein, which costs more energy to digest and keeps you fuller, and protecting your muscle with strength training.

    For the full picture of how your body uses energy, including why metabolism barely changes between ages 20 and 60, see our main metabolism guide. This page checks one popular claim: that particular foods “boost” or “rev up” your metabolism enough to help you lose weight. We look at each favorite, the size of the effect in real numbers, and what is worth doing instead. It is general education, not personal advice.

    How food affects metabolism at all

    Every day your body spends energy in three ways: keeping you alive at rest (basal metabolic rate), moving, and digesting and storing food. That last part is called the thermic effect of food, or diet-induced thermogenesis. A 2004 review by Klaas Westerterp found that on a mixed diet, digestion accounts for 5 to 15% of daily energy use. The amount depends mostly on how much you eat and on what: protein and alcohol cost the most to process, carbohydrates less, and fat very little.

    Share of a nutrient's calories used up in digesting itValues in %
    Share of a nutrient's calories used up in digesting it
    ItemLowHigh
    Protein20%30%
    Carbohydrate5%10%
    Fat0%3%

    Alcohol is reported at 10-30%. On a mixed diet the total is 5-15% of daily energy use.

    Source: Westerterp KR, Nutrition & Metabolism 2004 (review of diet-induced thermogenesis) (checked on October 7, 2026)

    That chart is the most useful fact in this whole topic. It means no single “magic” food sets your metabolism on fire; the biggest food-related lever you have is the protein share of your meals. It also quietly debunks the “negative-calorie food” idea. Celery, cucumber and grapefruit are low in calories, which makes them great for filling up, but because digestion uses only a fraction of the calories a food provides (at most around 30% for protein), no food costs more energy to digest than it gives you.

    The usual suspects, checked

    Chili peppers (capsaicin). Capsaicin, the compound that makes chili hot, and its milder relatives called capsinoids do raise energy use a little. A 2018 meta-analysis pooled nine studies and found an average increase of about 245 kilojoules, or 59 calories, a day. The effect showed up only in studies of people with a BMI above 25 (about 70 calories a day) and not in leaner groups. Most studies gave capsaicin as a measured dose, often in capsules, not as a sprinkle of chili flakes on dinner.

    Coffee and caffeine. Caffeine is a genuine stimulant. In a classic 1989 study, a single 100 mg dose (less than one 12-ounce cup of coffee, going by the FDA’s estimate that 400 mg is about two to three cups) raised resting metabolic rate by 3 to 4% for two and a half hours. When volunteers took 100 mg every two hours for 12 hours, their daily energy use rose by about 150 calories in lean people and 79 calories in people who had previously had obesity. But that schedule adds up to 600 mg a day, more than the 400 mg the FDA cites as an amount not generally associated with negative effects for most adults. A 2019 meta-analysis of 13 trials linked caffeine intake with slightly more weight loss, but the studies were very different from one another, so the size of any real effect is uncertain.

    Green tea. Green tea contains catechins plus caffeine. A 2011 meta-analysis of respiration-chamber studies found that catechin-caffeine mixtures raised 24-hour energy use by 4.7%, or about 428 kilojoules (around 100 calories), and caffeine alone did almost the same (4.8%). That sounds promising, but when the Cochrane Collaboration looked at what actually happened to body weight in longer trials outside Japan, green tea preparations led to a difference of just 0.04 kg, which was not statistically significant. Concentrated green tea extract has been linked with cases of liver damage, according to the NIH Office of Dietary Supplements; see our green tea extract page before trying pills.

    Ice-cold water. A 2003 study made headlines by reporting that drinking 500 ml of water raised metabolic rate by 30%, a total of about 100 kilojoules (roughly 24 calories). When a different team retested the idea in 2006, room-temperature water did not raise energy use at all, and water chilled to 3°C produced only a small 4.5% rise over an hour, well below the energy needed to warm it to body temperature. Drinking water is still a good habit, especially in place of sugary drinks, but not because it “burns” calories.

    Extra calories burned per day in the studies (approximate)Values in kcal
    Extra calories burned per day in the studies (approximate)
    ItemValue
    Caffeine 100 mg every 2 h for 12 h (lean)150 kcal
    Caffeine-only capsules (chamber studies)103 kcal
    Green tea catechins + caffeine102 kcal
    Capsaicin or capsinoids59 kcal
    500 ml of water (2003 study)24 kcal

    Kilojoules converted to kcal (1 kcal = 4.184 kJ). Lab doses, not everyday servings; a 2006 retest found no rise with room-temperature water.

    Source: Dulloo AG et al. AJCN 1989; Hursel R et al. Obesity Reviews 2011; Zsiborás C et al. Crit Rev Food Sci Nutr 2018; Boschmann M et al. JCEM 2003 (checked on October 7, 2026)

    “Fat-burning” spices, vinegar and grapefruit. Cinnamon, ginger, apple cider vinegar and grapefruit are often added to “metabolism” lists. They can be part of a tasty, healthy diet, but we did not find good human evidence that any of them raises daily energy use by a meaningful amount. Supplements built on these ingredients are a different story, and many make claims their evidence can’t support; our pages on fat burners and “nature’s Ozempic” supplements explain why.

    Eating little and often to “stoke the fire”. Because digestion uses energy, some diets claim that six small meals keep metabolism higher than three larger ones. But the thermic effect depends on the total amount and type of food, not on how it is split up. In a 2010 trial, 16 adults on the same calorie-reduced diet for eight weeks ate either three meals a day or three meals plus three snacks. Both groups lost weight (about 4.7% on average), with no difference between them in body fat, appetite or hunger hormones. Eat on the schedule that keeps you comfortable and in control of portions.

    Put the numbers in context

    Tens of calories a day can sound useful, but they are easy to cancel out. A medium apple has about 95 calories, according to the USDA’s food database, which is more than any everyday food “booster” adds. Add sugar and cream to a coffee, and the drink can easily bring in more calories than its caffeine burns.

    What really sets your daily energy use

    Checked on October 7, 2026

    Two things move the needle more than any single food. First, the size of your body and how much muscle you carry: each kilogram of muscle burns about 13 calories a day at rest, compared with about 4.5 for a kilogram of fat. That is not huge either, but muscle also lets you be more active. Second, how much you move. Our TDEE calculator estimates your total daily energy use from your size and activity level, and the calories burned calculator shows what a walk or workout adds.

    What does help: protein, muscle and movement

    Protein at every meal. Protein has the highest thermic effect, and the Westerterp review links that extra energy use to feeling fuller. In a respiration-chamber study, a diet with 29% of calories from protein (and plenty of carbohydrate) used 14.6% of its energy in digestion versus 10.5% for a high-fat diet, and people felt more satisfied. Over weeks, a 2012 meta-analysis of trials found that higher-protein, energy-restricted diets led to more fat loss and helped protect lean mass and resting energy use compared with standard-protein diets. Our high-protein diet guide, the protein calculator and the best high-protein breakfasts make it practical.

    Strength training. Muscle is the tissue you can most easily add, and it matters even more while you lose weight, when some lean mass is usually lost too. Two or more sessions a week, as the Physical Activity Guidelines suggest, is a good start; see our strength training guide.

    Filling, lower-calorie foods. The “metabolism foods” that really help weight loss do it by filling you up for fewer calories, not by burning more. Vegetables, fruit, beans, lean proteins and soups top our list of the best filling foods, and swapping sugary drinks for water, unsweetened tea or black coffee helps too (see weight-loss drinks).

    Swap the boosters for these

    1. Anchor meals with proteinEggs, Greek yogurt, fish, chicken, tofu or beans at breakfast, lunch and dinner.
    2. Fill half the plate with produceHigh-volume vegetables and fruit fill you up for few calories.
    3. Keep coffee and tea simpleBlack or lightly sweetened; stay within about 400 mg of caffeine a day, as the FDA cites for most adults.
    4. Lift twice a weekFull-body strength work protects muscle while you lose weight.
    5. Move more every dayWalks and everyday activity add far more than any food can.

    When metabolism really is the issue

    Some medical conditions do affect weight: the NIDDK lists weight gain, tiredness and feeling cold among common symptoms of an underactive thyroid. If you are gaining weight without a change in habits, or also feel unusually tired or cold, talk with your clinician rather than trying “boosting” products. And if you have lost a lot of weight, your energy needs really do fall: in a well-known follow-up of TV contestants who lost 58 kg on average, resting metabolism was still about 500 calories a day lower than expected six years later. That is a reason to plan for maintenance, which our keeping weight off guide covers, not a reason to buy metabolism pills.

    The verdict

    Metabolism-boosting foods are mostly fiction, with a grain of truth. Capsaicin, caffeine and green tea raise energy use a little in the lab, and protein really does cost more to digest, but none of them add up to meaningful weight loss on their own. Enjoy chili, coffee and tea if you like them. Then put your effort where the evidence is: enough protein, plenty of filling plants, regular strength training and daily movement, inside a calorie deficit you can live with. For more claims checked against the studies, see our weight-loss myths roundup and the nutrition hub.