>Speaking of which, one idea the calorie-restriction people kick around
>is whether previous nutritional research, particularly on the benefits
>of vegetarianism and low-fatness, were actually studies of mild calorie
>restriction. Is it "fat bad (for some chemical reason)" or "excess
>calories bad, and fat translates to lots of calories"?
Rats fed high-fat but low calorie diets do about as well as rats fed low-fat
low-calorie diets. So the conclusion is that the *primary* health
disadvantage of fat is that it makes you eat more. Fat may have other
disadvantages wrt heart disease or reproductive cancers (research is
inconclusive; I've seen studies both ways). With humans there is little
research on the effect of changing fat intake without changing calorie intake
- over a lifetime, these are correlated and very hard to separate.