History
A history of diet fads from 1900 to 2026, from Fletcherism and calorie counting to Atkins, liquid protein, low-fat, detoxes, paleo, fasting and keto, with what the evidence said later.
Key takeaways
- In the first randomized trial of the Atkins diet (2003), low-carb led to more weight loss at 3 and 6 months, but the 12-month difference was not significant.[12]
- Liquid-protein diets of about 300 to 400 calories a day were linked to 17 sudden deaths from heart rhythm problems studied in a 1981 report.[14]
- Atkins, Zone, Weight Watchers and Ornish led to similar weight loss at one year (2.1 to 3.3 kg); adherence, not diet type, predicted results.[16]
- In the Women's Health Initiative, a low-fat eating pattern did not cause weight gain over 7.5 years in 48,835 women.[15]
- The NIH says there is no compelling research supporting detox diets for weight management or removing toxins.[17]
In short: Diet fads have come in waves for more than a century: chewing every bite slowly in the 1900s, counting calories from 1918, books in the 1960s that said calories didn’t count, high-protein and low-carb plans from 1967 and 1972, dangerous liquid-protein fasts in the late 1970s, low-fat eating, then detoxes, paleo, intermittent fasting and keto. When researchers finally tested the famous ones head to head, the answer was surprisingly consistent: most produced similar, modest weight loss at a year, and the people who stuck with their plan lost the most. A few fads were harmful, and a few left lasting lessons.
This page covers diet fads from 1900 to today and what the evidence said about each one later. Dates come from the original books (several are now in the public domain) and National Library of Medicine catalog records; results come from randomized trials. For the wider story, including drugs, surgery and programs, see our history of weight loss; for today’s eating patterns ranked by evidence, see the 10 best diets for weight loss.
Diet fads at a glance, 1900 to 2026
- 1900sFletcherism: chew every mouthful slowly and thoroughly.
- 1918Calorie counting goes mainstream with Lulu Hunt Peters.
- 1960s"Calories don't count" and the quick-weight-loss diet.
- 1970sAtkins' low-carb revolution, then deadly liquid-protein fasts.
- 1980s-2000sLow fat vs low carb: the "diet wars".
- Recent decadesDetoxes, paleo, intermittent fasting and keto, each later tested in trials.
- 2020sBig analyses find most diets work about equally; GLP-1 medicines change how people eat.
Before 1900: the first diet bestseller
The modern diet book starts in 1863 with William Banting’s Letter on Corpulence, in which a Londoner described losing 46 pounds by cutting bread, sugar, beer and potatoes. “Banting” became a word for dieting, and his low-starch idea came back again and again over the next 160 years, as this page shows. Our history pillar tells his story in full.
1900s: Fletcherism, or “chew, chew, chew”
Horace Fletcher, an American businessman, became famous in the early 1900s for one rule: chew food very slowly and thoroughly before swallowing. His books include The A.B.-Z. of Our Own Nutrition (1903) and Fletcherism: What It Is (1913). In the 1913 book he wrote that at 40 he weighed 217 pounds, about 50 more than he thought right for his height, and that after he started chewing carefully he lost more than 60 pounds of fat. He noted that a dozen years earlier the idea had been laughed at as the “chew-chew” cult. The habit spread widely enough that the book quotes a newspaper report of John D. Rockefeller telling people to “Fletcherize, or chew very slowly”.
What the evidence said later: partly supported. Fletcher’s claims about digestion and health went far beyond the evidence, but one piece holds up. A 2014 meta-analysis of 22 experiments found that eating more slowly led people to eat less at that meal, though it did not change how hungry they felt afterward. Slow, mindful eating is still a reasonable tool, not a weight-loss plan on its own.
1918: the calorie arrives
Physician Lulu Hunt Peters’ Diet and Health, With Key to the Calories (1918) taught readers to think of food in calories, with tables to make counting practical. It was less a fad than a framework that every later diet would either embrace or try to escape. What the evidence said later: supported. Calorie balance still sits at the core of weight loss: a 2014 JAMA analysis of 48 trials of named diets found that any low-carbohydrate or low-fat diet produced significant weight loss, and the differences between named diets were small. Our calorie deficit guide and calorie calculator use modern equations.
1960s: “calories don’t count” and the quick-weight-loss diet
By the 1960s, a new kind of diet book argued against counting. Herman Taller’s Calories Don’t Count (1961) made the case in its title. Irwin Maxwell Stillman’s The Doctor’s Quick Weight Loss Diet (1967) put speed in its title. Fast, effortless results became the standard promise of the diet book.
What the evidence said later: “calories don’t count” not supported; quick loss rarely lasts. When trials compared diets with very different mixes of fat, protein and carbohydrate, weight loss was similar, which is why the idea that calories don’t matter has not held up. As for speed, the NIH today recommends an initial goal of 5% to 10% of starting weight over six months. One macronutrient idea of the era does have modest support: higher-protein diets led to 0.79 kg more weight loss and better retention of lean mass than standard-protein diets with the same calories in a meta-analysis of 24 trials. Our high-protein diet guide covers the modern version.
1972: Atkins and the low-carb revolution
Robert C. Atkins’ Dr. Atkins’ Diet Revolution (copyright 1972) became one of the best-known diet books ever. Its core idea, sharply cutting carbohydrates while eating protein and fat freely, was Banting’s idea updated, and it returned in waves for decades.
What the evidence said later: works, but not magic. The first randomized trial of the Atkins diet did not appear until 2003. In that New England Journal of Medicine trial of 63 adults, the low-carb group lost more weight at 3 and 6 months, about 4 percentage points more, but by 12 months the difference was no longer significant. Larger trials followed. In Stanford’s A TO Z study of 311 women, Atkins led to the most weight loss at 12 months (4.7 kg), but only its difference from the Zone diet was significant.
| Item | Low-carbohydrate (Atkins) | Conventional low-fat |
|---|---|---|
| 3 months | 6.8% | 2.7% |
| 6 months | 7% | 3.2% |
| 12 months | 4.4% | 2.5% |
Percent of body weight lost. The 12-month difference was not significant. Adherence was poor and dropout high in both groups.
Source: Foster GD et al., New England Journal of Medicine 2003 (63 adults) (checked on October 6, 2026)
Late 1970s: liquid protein, the fad that killed
The darkest chapter came in the late 1970s with very-low-calorie “liquid protein” diets, in which people lived for months on protein drinks of about 300 to 400 calories a day. A 1981 investigation in the American Journal of Clinical Nutrition, by researchers including FDA and CDC staff, studied 17 people who died suddenly of heart rhythm problems after using these regimens for a median of five months. The deaths happened regardless of medical supervision or the protein product used, and the heart damage resembled that seen in starvation. The authors called for these regimens to be curtailed.
What the evidence said later: harmful as practiced. Today’s medically supervised very-low-calorie programs and meal-replacement shakes use complete nutrition, higher protein quality and limited time frames, and they are a different thing. Anyone considering an extreme low-calorie plan should do it only with medical supervision.
1980s to 2000s: low fat vs low carb
Low-fat eating was widely promoted in this period, and low-carb proponents pushed back, some suggesting that low-fat, high-carbohydrate diets were partly to blame for rising obesity. That argument was tested directly in the Women’s Health Initiative, which randomly assigned 48,835 postmenopausal women to a low-fat eating pattern or to usual eating, with no weight-loss goal. Women in the low-fat group lost 2.2 kg on average in the first year and stayed slightly lighter over 7.5 years, with no tendency to gain. What the evidence said later: low fat did not cause weight gain, and did not cause much loss either.
The “diet wars” were finally settled, as far as weight goes, by head-to-head trials of the popular diets of the era. In a Tufts trial published in 2005, 160 adults were assigned to Atkins, Zone, Weight Watchers or Ornish. At one year, weight loss was similar across all four, about 2 to 3 kg, and the amount people lost was tied to how well they stuck to their diet, not to which diet they had.
| Item | Value |
|---|---|
| Atkins | 2.1 kg |
| Zone | 3.2 kg |
| Weight Watchers | 3 kg |
| Ornish | 3.3 kg |
Average weight lost at 1 year, counting dropouts as no change. Only 50% to 65% completed. Weight loss tracked adherence, not diet type.
Source: Dansinger ML et al., JAMA 2005 (160 adults, randomized) (checked on October 6, 2026)
More recent fads: detoxes, paleo, fasting and keto
Detoxes and cleanses: not supported. Juice cleanses, teas and colon cleanses promised to flush out “toxins” and weight. The NIH’s National Center for Complementary and Integrative Health says there is no compelling research supporting detox diets for weight management or removing toxins, warns about unpasteurized juices, laxatives and dangerous electrolyte imbalances from days without food, and notes that the FDA and FTC have acted against companies over hidden ingredients and false claims.
Paleo: partly supported. The idea is to eat like our hunter-gatherer ancestors. In a two-year Swedish trial of 70 postmenopausal women, a paleo-type diet led to more fat loss than a standard healthy diet at six months (6.5 vs 2.6 kg of fat), but by two years the difference was no longer significant, and triglycerides stayed lower in the paleo group.
Intermittent fasting: supported, but not better than counting. Plans such as 5:2 and time-restricted eating set when you eat rather than what. A 2025 BMJ analysis of 99 trials found every fasting style beat eating freely, but only alternate-day fasting edged out daily calorie restriction, and in trials of 24 weeks or more, none did better. Our intermittent fasting vs calorie counting comparison and intermittent fasting guide go further.
Keto: supported, with trade-offs. The very-low-carb ketogenic diet is the strictest modern heir of Banting and Atkins. A meta-analysis of 13 trials lasting a year or more found 0.91 kg more weight loss than low-fat diets, with better triglycerides and HDL but higher LDL cholesterol. See our keto guide before trying it, especially if you take medicines for diabetes or blood pressure.
Grapefruit, a fad that keeps returning: weak evidence. Grapefruit diets have come and gone many times. One small 12-week trial of 91 adults found that half a fresh grapefruit before meals led to 1.6 kg of weight loss, compared with 0.3 kg with a placebo, but no single food has been shown to “burn” fat, and grapefruit can interact with some prescription medicines, so ask your pharmacist.
What the evidence said later, fad by fad
| When | Fad | The promise | What the evidence said later |
|---|---|---|---|
| 1900s | Fletcherism | Chew slowly for health and weight | Partly: slower eating lowers intake at a meal |
| 1918 | Calorie counting | Weight follows calories | Supported: still the core of weight loss |
| 1961 | Calories Don’t Count | Food type matters, not amount | Not supported |
| 1967 | The Doctor’s Quick Weight Loss Diet | Fast results | Fast loss rarely lasts; 5% to 10% in 6 months is the realistic goal |
| 1972 | Atkins low-carb | Eat fat and protein, cut carbs | Supported short term; similar to others at 1 year |
| Late 1970s | Liquid protein fasts | Rapid loss on protein drinks | Harmful: sudden deaths reported |
| Tested 2006 | Low-fat eating | Fat makes you fat | No weight gain, but little loss without calorie goals |
| Recurring | Detoxes and cleanses | Flush toxins and pounds | Not supported; some risks |
| Tested 2014 | Paleo | Eat like our ancestors | Partly: early edge faded by 2 years |
| Reviewed 2025 | Intermittent fasting | When you eat matters most | Supported, about equal to calorie counting |
| Reviewed 2013 | Keto | Burn fat in ketosis | Supported, small edge; LDL rises |
| Recurring | Grapefruit | A food that burns fat | Weak: one small trial |
The 2020s: from fads to patterns
The biggest change in recent years is not a new diet but new evidence about old ones. A 2020 BMJ network meta-analysis of 121 trials and 14 named diets found that most produced similar weight loss at six months and that the effects shrank by twelve months for every diet, with only the Mediterranean diet keeping its heart-risk benefits. At the same time, GLP-1 medicines changed what many people eat, with more attention to protein, fiber and smaller portions; our eating on a GLP-1 guide covers that. The Mediterranean diet, never a fad, remains the best-supported long-term pattern on our list.
What the big diet analyses found
- 48randomized trials of named diets in a 2014 JAMA analysis: differences between diets were smallJohnston BC et al., JAMA 2014
- 121trials of 14 named diets in a 2020 BMJ analysis: weight loss shrank for every diet by 12 monthsGe L et al., BMJ 2020
- r = 0.60link between sticking to the diet and weight lost in the 2005 four-diet trial; diet type showed almost none (r = 0.07)Dansinger ML et al., JAMA 2005
Checked on October 6, 2026
How to spot the next diet fad
A century of fads offers a simple test. Be skeptical when a diet promises that one food, one nutrient or one rule overrides calories; when results are fast and effortless; when it bans whole food groups for everyone; or when it sells its own supplements. The FTC lists claims that can’t be true, such as weight loss “no matter what” you eat. Look instead for an eating pattern you could follow for years. Our weight-loss myths page checks popular claims against research, the diets hub compares today’s options, and the nutrition hub has everyday meal ideas. The rest of our history series covers weight-loss drugs and exercise fads.
Records in this article
Keto Diet: how it works, risks and who it suitsEvidence: Moderate · Hard
High-Protein Diet for Weight Loss: how much and from whatEvidence: Moderate · Moderate
Intermittent Fasting: 16:8, 5:2 and what the evidence showsEvidence: Moderate · Moderate
Mediterranean Diet for Weight Loss: foods, evidence and a 7-day starterEvidence: High · Easy
WeightWatchers (WW): Points, Med+ clinic and costsCommercial · Can prescribeRelated guides
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- Is the diet I am interested in safe with my health conditions and medicines?
- Would a lower-carb, lower-fat or Mediterranean pattern suit my blood tests best?
- Is a very-low-calorie plan appropriate for me, and if so, with what supervision?
- Could a registered dietitian help me find a pattern I can keep for years?
Frequently asked questions
What was the first fad diet?
William Banting's 1863 low-starch diet is often called the first diet bestseller. In the early 1900s, Horace Fletcher's slow-chewing "Fletcherism" became one of the first fads to sweep America.
Did the Atkins diet work?
In trials, Atkins led to faster early weight loss than low-fat diets, but by 12 months the results were usually similar. In one 2007 trial it led to the most loss at a year (4.7 kg), significantly more only than the Zone diet.
Why were liquid protein diets dangerous?
In the late 1970s, people lived for months on protein drinks of about 300 to 400 calories a day. A 1981 report studied 17 sudden deaths from heart rhythm problems, with heart changes like those seen in starvation.
Which diet fad actually works best?
Head-to-head trials found that most popular diets produce similar weight loss at a year, and sticking with the plan matters most. Long-term evidence is strongest for the Mediterranean diet, which was never a fad.
Do detox cleanses help you lose weight?
The NIH says there is no compelling research to support detox diets for weight management or removing toxins, and some carry risks such as dehydration and electrolyte imbalances.
References
- Banting W.. Letter on Corpulence, Addressed to the Public (1863). Project Gutenberg (public-domain edition), 1863. (accessed October 6, 2026) Other
- Fletcher H.. The A.B.-Z. of Our Own Nutrition (New York: F. A. Stokes, c1903), NLM Catalog record 475130. National Library of Medicine catalog, 1903. (accessed October 6, 2026) Other
- Fletcher H.. Fletcherism: What It Is; Or, How I Became Young at Sixty (1913). Project Gutenberg (public-domain edition), 1913. (accessed October 6, 2026) Other
- Robinson E, Almiron-Roig E, Rutters F, et al.. A systematic review and meta-analysis examining the effect of eating rate on energy intake and hunger. American Journal of Clinical Nutrition, 2014. doi:10.3945/ajcn.113.081745 · PMID 24847856 (accessed October 6, 2026) Meta-analysis
- Peters LH.. Diet and Health, With Key to the Calories (1918). Project Gutenberg (public-domain edition), 1918. (accessed October 7, 2026) Other
- Johnston BC, Kanters S, Bandayrel K, et al.. Comparison of weight loss among named diet programs in overweight and obese adults: a meta-analysis. JAMA, 2014. doi:10.1001/jama.2014.10397 · PMID 25182101 (accessed October 7, 2026) Meta-analysis
- Taller H.. Calories Don’t Count (New York: Simon and Schuster, 1961), NLM Catalog record 450620. National Library of Medicine catalog, 1961. (accessed October 6, 2026) Other
- Stillman IM, Baker SS.. The Doctor’s Quick Weight Loss Diet (Englewood Cliffs: Prentice-Hall, c1967), NLM Catalog record 124116. National Library of Medicine catalog, 1967. (accessed October 6, 2026) Other
- Choosing a Safe & Successful Weight-loss Program. National Institute of Diabetes and Digestive and Kidney Diseases (NIH). (accessed October 7, 2026) Government page
- Wycherley TP, Moran LJ, Clifton PM, Noakes M, Brinkworth GD. Effects of energy-restricted high-protein, low-fat compared with standard-protein, low-fat diets: a meta-analysis of randomized controlled trials. American Journal of Clinical Nutrition, 2012. doi:10.3945/ajcn.112.044321 · PMID 23097268 (accessed October 7, 2026) Meta-analysis
- Atkins RC.. Dr. Atkins’ Diet Revolution (New York: McKay, [1973, c1972]), NLM Catalog record 355420. National Library of Medicine catalog, 1972. (accessed October 7, 2026) Other
- Foster GD, Wyatt HR, Hill JO, et al.. A randomized trial of a low-carbohydrate diet for obesity. New England Journal of Medicine, 2003. doi:10.1056/NEJMoa022207 · PMID 12761365 (accessed October 7, 2026) Randomized trial
- Gardner CD, Kiazand A, Alhassan S, et al.. Comparison of the Atkins, Zone, Ornish, and LEARN diets for change in weight and related risk factors among overweight premenopausal women: the A TO Z Weight Loss Study. JAMA, 2007. doi:10.1001/jama.297.9.969 · PMID 17341711 · NCT00079573 (accessed October 6, 2026) Randomized trial
- Sours HE, Frattali VP, Brand CD, et al.. Sudden death associated with very low calorie weight reduction regimens. American Journal of Clinical Nutrition, 1981. doi:10.1093/ajcn/34.4.453 · PMID 7223697 (accessed October 6, 2026) Other
- Howard BV, Manson JE, Stefanick ML, et al.. Low-fat dietary pattern and weight change over 7 years: the Women’s Health Initiative Dietary Modification Trial. JAMA, 2006. doi:10.1001/jama.295.1.39 · PMID 16391215 · NCT00000611 (accessed October 7, 2026) Randomized trial
- Dansinger ML, Gleason JA, Griffith JL, Selker HP, Schaefer EJ. Comparison of the Atkins, Ornish, Weight Watchers, and Zone diets for weight loss and heart disease risk reduction: a randomized trial. JAMA, 2005. doi:10.1001/jama.293.1.43 · PMID 15632335 (accessed October 6, 2026) Randomized trial
- “Detoxes” and “Cleanses”: What You Need To Know. National Center for Complementary and Integrative Health (NIH). (accessed October 7, 2026) Government page
- Mellberg C, Sandberg S, Ryberg M, et al.. Long-term effects of a Palaeolithic-type diet in obese postmenopausal women: a 2-year randomized trial. European Journal of Clinical Nutrition, 2014. doi:10.1038/ejcn.2013.290 · PMID 24473459 (accessed October 6, 2026) Randomized trial
- Semnani-Azad Z, Khan TA, Chiavaroli L, et al.. Intermittent fasting strategies and their effects on body weight and other cardiometabolic risk factors: systematic review and network meta-analysis of randomised clinical trials. BMJ, 2025. doi:10.1136/bmj-2024-082007 · PMID 40533200 (accessed October 7, 2026) Meta-analysis
- Bueno NB, de Melo IS, de Oliveira SL, da Rocha Ataide T. Very-low-carbohydrate ketogenic diet v. low-fat diet for long-term weight loss: a meta-analysis of randomised controlled trials. British Journal of Nutrition, 2013. doi:10.1017/S0007114513000548 · PMID 23651522 (accessed October 7, 2026) Meta-analysis
- Fujioka K, Greenway F, Sheard J, Ying Y. The effects of grapefruit on weight and insulin resistance: relationship to the metabolic syndrome. Journal of Medicinal Food, 2006. doi:10.1089/jmf.2006.9.49 · PMID 16579728 (accessed October 6, 2026) Randomized trial
- Ge L, Sadeghirad B, Ball GDC, et al.. Comparison of dietary macronutrient patterns of 14 popular named dietary programmes for weight and cardiovascular risk factor reduction in adults: systematic review and network meta-analysis of randomised trials. BMJ, 2020. doi:10.1136/bmj.m696 · PMID 32238384 (accessed October 7, 2026) Meta-analysis
- Gut Check: A Reference Guide for Media on Spotting False Weight Loss Claims. Federal Trade Commission, 2014. (accessed October 7, 2026) Government page
Facts checked on October 6, 2026
Educational information, not medical advice. Talk with a qualified healthcare professional about your own situation. In an emergency call 911.
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