Sherry Pagoto, a clinical psychologist and professor at UMass Med School, has an editorial in the most recent JAMA calling for an End to the Diet Debates, specifically wrt diet composition. Here’s part of the abstract:
Numerous randomized trials comparing diets differing in macronutrient compositions (eg, low-carbohydrate, low-fat, Mediterranean) have demonstrated differences in weight loss and metabolic risk factors that are small (ie, a mean difference of <1 kg) and inconsistent. …
The only consistent finding among the trials is that adherence—the degree to which participants continued in the program or met program goals for diet and physical activity—was most strongly associated with weight loss and improvement in disease-related outcomes. The long history of trials showing very modest differences suggests that additional trials comparing diets varying in macronutrient content most likely will not produce findings that would significantly advance the science of obesity.
And in other news, Gary Taubes is in Scientific American’s special issue on food suggesting that “rigorously controlled studies may soon give us a definitive answer about what causes obesity—excessive calories or the wrong carbohydrate.”
Since long-time readers know I’m not really a fan of Taubes’ carbs-insulin hypothesis, I must admit to thinking that Dr. Pagoto has a point. Here she is talking about why we need to look elsewhere:
Now I get why Dr. Pagoto, as a behavioral scientist, wants to shift the conversation. For one, in an interview with WBUR, she makes an important point that diet proponents tend to gloss over:
Stress is a huge factor in undermining adherence in any diet, undermining adherence to an exercise program. … The most common thing a patient will say is, ‘I want to lose weight, but life is getting in the way.’ And what they mean is, “I am struggling with figuring out how to make these changes last and stick given everything else I’ve got to do.’ And that’s what they need help with. That’s a behavioral science question. It’s not a nutrition question per se.
Interestingly, there may be other reasons why this focus on macronutrients may be perpetually inconclusive. Writer David Freedman suggests that one of these is that, like the drunk man looking for his keys in the light, researchers are often just looking where the looking is good:
Many, and possibly most, scientists spend their careers looking for answers where the light is better rather than where the truth is more likely to lie. They don’t always have much choice. It is often extremely difficult or even impossible to cleanly measure what is really important, so scientists instead cleanly measure what they can, hoping it turns out to be relevant.
I’m not holding my breath that we’ll see an end to the diet debates any time soon, but I will certainly welcome more conversations that aren’t about macronutrients. I don’t think that’s where the answer lies.