Myths About the Failure Rate of Dieting
People have been pointing out the very high failure rate of intentional weight loss attempts since before I was born. We can quibble over the exact percentage, but there is no denying that the research shows that the vast majority of people lose weight short term then gain their weight back long term, that many gain back more than they lost, and that the weight cycling that is, by far, the most common outcome is independently linked to harm.
We’ve known this since at least the 1950s, but many healthcare practitioners are still recommending/prescribing weight loss constantly to their higher weight patients. In the thirteen years that I’ve been giving talks and consultations to healthcare practitioners about this, there are some persistent myths about this failure rate that they believe (and were often taught during their education/certification) so I wanted to try to clear them up today.
The failure rate only applies to “fad” diets
There is a belief that when we talk about the failure rates of intentional weight loss (IWL,) we are only talking about “fad” diets, or commercial diet programs. In fact, the research looks at all attempts to manipulate body size using food and/or movement. (Note that diet drugs and surgeries also have high failure rates, but they often post much higher risks, so I typically discuss them separately.) If we’re talking about lifestyle interventions that are prescribed to manipulate bodies to a lower size, we’re also talking about a failure rate of around 95%.
It’s just that one study from the 1950s
When people claim this, they are talking about Stunkard et al. This study followed 100 patients who were put on diets and found the 95 of them failed, but they also analyzed the research for the previous 30 years to find that intentional weight loss attempts had abysmal success rates. And it’s certainly not just this study - this has been found in plenty of research since then.
Weight loss works, it’s just that people don’t do it right
First of all, this is not what the research shows, but that’s a subject for another post. The bottom line is that around 95% of people regain all of their weight with up to 66% gaining back more than they lost. I don’t think there’s anything wrong with being fat or getting fatter, I do think there is something deeply wrong with a so-called healthcare intervention that fails almost all the time and has the opposite of the intended effect the majority of the time. Even if the reason is that 95% of people just “don’t do it right”, the failure rate would still matter, the harm caused by weight cycling would still be real, and this would still require a hefty informed consent conversation rather than just shrugging one’s shoulders and blaming one’s patients. If there was a drug with these kinds of failure rates, I sincerely hope that doctors wouldn’t spend half a century prescribing it and just telling people to try harder at taking it.
IWL fails 95% of the time, so you just have to keep trying until you’re in the 5%
This one would be funnier if it didn’t harm so many people. I can’t even count the number of healthcare practitioners who have said something like this to me. I know everyone didn’t study statistics and of course that’s fine – but I did. So you can take my word for it, or you can look it up, but this absolutely is not how statistics work (though the people who sell lottery tickets would definitely like us to think that it is.) Everyone can’t be in the 5%.
It’s a shame that so many healthcare practitioners are failed by an education that is rooted in weight stigma rather than facts that teaches them to harm their fat patients under the guise of care. But it’s never too late to learn and do better for fat patients.
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*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.