The New England Journal of Medicine has published a paper by a number of leading obesity researchers titled, “Myths, Presumptions, and Facts About Obesity“. It details what the authors describe as seven popular obesity related “myths“, six common “presumptions“, and nine understated evidence supported “facts“. However, Dr Yoni Freedhoff, on his blog Weighty Matters, gives his take on the myths and doesn’t agree in all cases…
These are subjects that the authors feel have sufficient data to conclusively dismiss them as false. While I agree in some cases, I don’t in all. That doesn’t necessarily mean the authors are wrong and that I’m right, just that our opinions differ:
1. “Small sustained changes in energy intake or expenditure will produce large, long-term weight changes”.
(Agree this is a myth. Putting this another way, I’ll often tell my patients weight loss is insert-adjective here. Meaning small changes only lead to small losses and if you want to lose a huge amount of weight, you’ll need to undertake (and sustain) a huge amount of change.)
2. “Setting realistic goals for weight loss is important, because otherwise patients will become frustrated and quit”.
(Disagree. Not that the statement’s true or false, just that the authors call it a myth consequent to the fact that there isn’t robust evidence proving it to be true or false. Until there’s robust evidence one way or the other, tough to call this one a myth and I’d have put it into their “presumptions” section. Moreover, tough to apply to everyone as no doubt some people likely respond wonderfully to aggressive goals, while others quit consequent to not reaching a dream destination.)
3. “Large, rapid weight loss is associated with poorer long-term weight-loss outcomes as compared with slow, gradual loss”.
(Disagree. Here again is an area where I don’t think we have sufficient data. The authors refer to year-long studies as long term data and frankly I don’t think that’s long term. For instance if a person rapidly loses 80lbs during an 8 month meal-replaced, very-low-calorie-diet looking at 1 year as “long term” only gives that person 4 months to regain. So I’d argue anything less than 2 year data is a short-term outcome and that we need data from at least 2 or more years out to draw long term conclusions and that’s truly rare to come by.)
4. “It is important to assess the stage of change or diet readiness in order to help patients who request weight-loss treatment”
(Disagree. Here the authors report that studies that have looked at stage of change in people voluntarily entering weight loss programs didn’t predict outcomes. Yet as the authors themselves point out, by definition folks voluntarily choosing to enter weight loss programs are at least minimally ready to face change. But for the clinician working their primary practice and not a practice like mine for instance, no doubt stage of change assessment crucial – if not for success than certainly for a respectful doctor patient relationship.)
5. “Physical-education classes in their current form, play an important role in reducing or preventing childhood obesity”
(Here all I can say is AMEN. No doubt evidence very clearly suggests kids aren’t going to burn off or prevent obesity by means of school based PE classes.)
6. “Breast-feeding is protective against obesity”
(The authors report that a WHO meta-analysis on the subject was flawed, and that well controlled trials failed to demonstrate any clear benefit to breastfeeding on reducing obesity risk.)
7. “A bout of sexual activity burns 100 to 300 kcal for each participant”
(By their calculations the authors predict the average act of intercourse burns in the neighbourhood of 14 calories (sorry folks).)
More (including the lists of ‘presumptions’ and ‘facts’) at Weighty Matters: The New England Journal’s Obesity Mythbusting