Another view on the 95%-of-diets-fail factoid: a survivors bias? I made a simple model based on population changes to get a bit of insight in the 95%-of-diets-will-fail factoid. Hope it helps a bit. Assumptions: (1) Every year 100 people become fat. (2) 1 in 2 of these is an idiot, already ingrained with fat logic, no clue about food, and lies to himself and his doctor. (3) Any fatty has a 50% change it will try a diet that year. (4) An idiot will try the all-you-can-eat-butter-and-sugar diet and will fail. (5) A non-stupid fatty will try the eat-less-move-more diet and thus succeeds. (6) A fatty has a 1 in 40 chance it will die that year. Results: We will have a stable population of 666 idiot fatties and 91 non-idiot fatties, giving us an overall diet success rate of only 12%. But remember all non-idiots have a diet success rate of 100%! It is just that the idiots fats are able to survive the diet (i.e. not get thin) and are thus able to fail at a diet many, many times, while the normal fat will only succeed only once at a diet.