If it's worth saying, but not worth its own post (even in Discussion), then it goes here.
Notes for future OT posters:
1. Please add the 'open_thread' tag.
2. Check if there is an active Open Thread before posting a new one. (Immediately before; refresh the list-of-threads page before posting.)
3. Open Threads should be posted in Discussion, and not Main.
4. Open Threads should start on Monday, and end on Sunday.
Yes, the effect of diets on weight-loss is roughly mediated by their effect on caloric intake and expenditure. But this does not mean that "eat fewer calories and expend more" is good advice. If you doubt this, note that the effect of diets on weight-loss is also mediated by their effects on mass, but naively basing our advice on conservation of mass causes us to generate terrible advice like "pee a lot, don't drink any water, and stay away from heavy food like vegetables".
The causal graph to think about is "advice → behavior → caloric balance → long-term weight loss", where only the advice node is modifiable when we're deciding what advice to give. Behavior is a function of advice, not a modifiable variable. Empirically, the advice "eat fewer calories" doesn't do a good job of making people eat fewer calories. Empirically, advice like "eat more protein and vegetables" or "drink olive oil between meals" does do a good job of making people eat fewer calories. The fact that low-carb diets "only" work by reducing caloric intake does not mean that low-carb diets aren't valuable.
I think it has a net negative effect on the global dieting discussion that it contains these superfluous steps to the actual causes of weight loss.... (read more)