I found a fascinating PDF file* on the internet regarding certain myths about dieting/nutrition. One of the myths mentioned was the oft-quoted “98% of diets fail” statistic. This paper makes a valiant effort to show why the number is a myth but, in my opinion, falls short.
Why? Because they claim the number comes from the Ancel Keys study (which they refer to as “a single study performed during WWII.”) They fail to mention that the Ancel Keys Biology of Human Starvation study is considered the source for information about human behaviour under conditions of food restriction. The study was NOT undertaken with a view to assess the effectiveness of ‘dieting.’
The purpose of the study was to place subjects on the same rations estimated to be available in war-torn countries of Europe in order to see how people could be expected to react, and to determine a minimum level of food consumption for health and well-being. The volunteer subjects were expected to endure these restricted rations only for a certain period of time, and then undergo a ‘refeeding’ period where they regained weight and went back up to their normal level of food intake, and then assessed to see if any long-term effects of the restriction lingered. [See Ancel Keys, The Biology of Human Starvation, 1950.]
Under these conditions, how could anyone cite this study as measuring the effectiveness of weight loss diets? These men were INTENDED to gain back whatever weight they lost, so it would be impossible to determine if their ‘diet’ (aka ‘semistarvation period’) was ‘successful.’
Hogwash. None of the sources I have seen that use the 98% statistic have cited Ancel Keys’ study as the originator of this number. The most reasonable-sounding explanation so far is that this number was obtained from the Aldebaran letter, which cites a poll which I have yet to find.
Furthermore, this paper cites The National Weight Control Registry as ‘encouraging’ evidence that weight loss and weight-control are not hopeless. I have read elsewhere that this registry consists of about 3,000 weight loss successes, and their definition of ‘success’ is something like “losing an average of 66 pounds and gaining back less than 30 pounds within 5.5 years.” Not exactly flying colours, eh?
If the 98% figure is true, The National Weight Control Registry may actually be VERIFYING it with their numbers…the statistics regarding how many Americans are dieting at any given time are HUGE…even only 2% of this number would still be a considerable amount of people, though clinically insignificant. According to the Calorie Control Council, 51 million Americans are dieting. 51 million. Do you know what 2% of 51 million is? It’s over 1 million. 1 million, 20 thousand, to be exact. If the 98% figure is actually TRUE, then over 1 million people should have successfully lost weight (or lost “an average of 66 pounds and gained back less than 30 pounds over 5.5 years.”) Out of over one million people, only 3,000 of them managed to sign up with the National Weight Control Registry? 0.3% of successful dieters (which is only .00006% of all dieters?) Something seems MIGHTY fishy here. I don’t think the Registry is doing any favours for the diet industry if they can only show a success rate of 0.00006% for all dieters.
Anyway, the idea that the 98% figure originates from a study undertaken when ‘dieting’ was less common than it is today, and undertaken to study the effects of semi-starvation, not the effectiveness of dieting, is just silly. The 98% figure may very well be a myth, but if it is, it certainly isn’t one that originated from this particular study.
The rest of the PDF paper is interesting though, and I’ll be sure to read it and check out its sources.
* I just realized that this paper was written by Novartis (Optifast.) You know who Optifast are, don’t you? Remember that time Oprah lost all that weight on a liquid protein diet? And then gained it all back? *cracking up* The paper also cites a study, “the largest and longest ever published by a weight-management organization” (not exactly great merits, since most ‘weight-management organizations’ aka diet companies don’t publish such studies because the results are not to their liking…just try asking Weight Watchers or Jenny Craig for their official success statistics if you don’t believe me…) which was PERFORMED by Optifast. So much for objective sources! *still laughing*
This is turning into a wild goose-chase. I have yet to hear back from the founder of NAAFA on the 98% statistic. I think I will start checking out that ‘poll’ mentioned in the Aldebaran letter.
2 responses to “98% figure and Weight Control Registry.”
I have read elsewhere that this registry consists of about 3,000 weight loss successes, and their definition of ’success’ is something like “losing an average of 66 pounds and gaining back less than 30 pounds within 5.5 years.” Not exactly flying colours, eh?
I have the paperwork to join the National Weight Control Registry but keep forgetting to send it back in. I have successfully maintained a weight loss of 100 pounds for six years, but I initially lost 175 pounds. In my case, my loss was due to a serious eating disorder, so the fact that I have regained some of the weight is to be expected and actually healthier for me than had I maintained an unnaturally low, unsustainable weight.
I agree that dieting “success” rates are pretty dismal, but I don’t think the fact that only 3,000 people are included on the registry is entirely indicative of overall failure rates. Many people aren’t aware of the registry and those who are motivated to sign up for it have to fill out a lot of time consuming paperwork in order to be included. I found out about it within the past couple of years and only because I stumbled across it while doing some related academic research on dieting and weight loss. I have compiled a list of other studies conducted in the past two decades on dieting that show very high failure rates. If you’d like it, send me an email and I’ll send it to you.
Yes, that’d be great. Thanks.
(ETA: FYI to everyone — These are old posts from my archive. I posted this one in particular because it turned out that a similar analysis was done, and published, in 2005: http://www.ncbi.nlm.nih.gov/pubmed/16029691)