Who Says Dieting Fails Most Of The Time?
A research timeline of the epic failure of weight loss interventions
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When I talk about the fact that the failure rate of intentional weight loss attempts is around 95%, there are a couple common ways that people push back. The first is claiming that this only applies to “fad diets” which is simply not true. There is no method of body size manipulation (whether we’re calling it a diet, a lifestyle change, a health journey, medically supervised weight management, or something else) that reliably produces significant long-term weight loss in more than a tiny fraction of people.
The other common pushback is that the 95% number was “only one study from the 1950’s” This, too, is completely false.
Today I thought we’d get a timeline of the highlights of diet failure going:
1959
A. Stunkard and M. McLaren-Hume
This is the first study that is typically credited with the 95% failure rate number, it also examines the previous 30 years of data. I did a deeper dive into this study here.
1992
The National Institutes of Health
“In controlled settings, participants who remain in weight loss programs usually lose approximately 10% of their weight. However, one third to two thirds of the weight is regained within 1 year, and almost all is regained within 5 years.”
1999
“Although long-term follow-up data are meager, the data that do exist suggest almost complete relapse after 3-5 yr.”
2007
“The authors review studies of the long-term outcomes of calorie-restricting diets to assess whether dieting is an effective treatment for obesity. These studies show that one third to two thirds of dieters regain more weight than they lost on their diets, and these studies likely underestimate the extent to which dieting is counterproductive because of several methodological problems, all of which bias the studies toward showing successful weight loss maintenance. In addition, the studies do not provide consistent evidence that dieting results in significant health improvements, regardless of weight change. In sum, there is little support for the notion that diets lead to lasting weight loss or health benefits.”
2010
L. Aphramor
“The best available evidence demonstrates that conventional weight management has a high long-term failure rate. The ethical implications of continued reliance on an energy deficit approach to weight management are under-explored.”
2013
Australian National Medical Health and Research Council Obesity
“Weight regain is common after weight loss that is achieved with lifestyle interventions. Weight loss is maximal at six to 12 months. Regardless of the degree of initial weight loss, most weight is regained within a two-year period and by five years the majority of people are at their pre-intervention body weight” Grade A Evidence
2015
“The annual probability of achieving normal body weight was 1 in 210 for men and 1 in 124 for women with simple ob*sity. The probability declined with increasing BMI category. In m*rbidly ob*se patients, the annual probability of achieving normal weight was 1 in 1290 for men and 1 in 677 for women. In women, the probability of achieving normal weight among superob*se participants was 1 in 608, which is similar to that observed among m*rbidly ob*se participants. In the smaller number of superob*se men, the probability was higher at 1 in 362.”
2020
Panel of Canadian Ob*sity Experts
“The common medical advice to eat less and exercise more doesn’t really help most patients…whenever people decrease their calories, they activate a bunch of hormones and neurochemicals within their brain, within their gut, that drive the weight to come back on. So we’re failing people all the time when we say go on a diet so they can lose a little bit of weight, [because they often] regain all of it, if not more,”
What’s more, research tells us that even when weight loss is “successful” it isn’t necessarily linked to greater health or improved mortality, while lifestyle interventions are:
2013
“Overall, there were only slight improvements in most health outcomes studied…There were a few larger positive effects for hypertension and diabetes medication use, as well as diabetes and stroke incidence. In correlational analyses, however, we uncovered no clear relationship between weight loss and health outcomes related to hypertension, diabetes, or cholesterol, calling into questions whether weight change per se had any causal role in the effects of the diets. Increased exercise, healthier eating, engagement with health care system and social support may have played a role instead.
2021
Gaesser and Angadi
“Weight loss, even if intentional, is not consistently associated with lower mortality risk”
“The mortality risk associated with ob*sity is largely attenuated or eliminated by moderate-to-high levels of cardiorespiratory fitness (CRF) or physical activity (PA)”
I wrote about this one more in-depth here.
2024
“The public health strategy has largely focused on weight loss; however, this has a recidivism rate of ~100% at 10 years follow-up. In addition, intentional weight loss alone has not consistently shown improvements in mortality risk in observational studies or randomized controlled trials.”
“Our analyses found that those classified as fit, regardless of BMI status, showed no statistically significant increase in CVD or all-cause mortality risk compared with normal weight-fit individuals.”
“In contrast, all BMI classifications who were “unfit” showed twofold to threefold increases in risk of CVD and all-cause mortality compared with normal weight-fit individuals.”
What I found when I did my first literature review of weight loss research in the early 2000’s is still true today. There isn’t a single study where more than a tiny percentage of participants are successful at significant, long-term weight loss. Among so-called “successes” the amount of weight lost is typically negligible, and the research does not suggest that subjects are healthier because of the weight loss, but rather that the same behavior changes that improve health can lead to the small (and likely temporary) weight loss.
The research shows us that (knowing that health is a complicated, multi-factorial concept and is not an obligation, barometer of worthiness, or entirely within our control) behaviors are a much better predictor of future health than is body size manipulation.
Let’s leave this failed paradigm behind and move forward into an ethical, evidence-based paradigm where we focus on reducing barriers, improving access, and working to support fat people’s health, rather than shrinking their bodies.
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More research and resources:
https://haeshealthsheets.com/resources/
*Note on language: I use “fat” as a neutral descriptor as used by the fat activist community, I use “ob*se” and “overw*ight” to acknowledge that these are terms that were created to medicalize and pathologize fat bodies, with roots in racism and specifically anti-Blackness. Please read Sabrina Strings’ Fearing the Black Body – the Racial Origins of Fat Phobia and Da’Shaun Harrison’s Belly of the Beast: The Politics of Anti-Fatness as Anti-Blackness for more on this.
Ragen you are doing the lord's work. This is such a helpful list to have.
I love this! Thank you for putting this together.