I am on mobile and I don't have a root source for the below paragraph, maybe someone can dig it up.
> The statistics for dieters who lose weight rapidly, according to Wellsphere, a website sponsored by Stanford University, is worse. Only 5 percent of people who lose weight on a crash diet will keep the weight off. Crash diets include any unhealthy diet, from severe calorie-restriction diets to diets that consist of only a few kinds of foods.
Another study showing 5% looks like it was an old study from 1959.
Anyway, there are more modern studies proving the point. And that people gain even more weight back than they started with.
http://newsroom.ucla.edu/releases/Dieting-Does-Not-Work-UCLA...
>Several studies indicate that dieting is actually a consistent predictor of future weight gain,” said Janet Tomiyama, a UCLA graduate student of psychology and co-author of the study. One study found that both men and women who participated in formal weight-loss programs gained significantly more weight over a two-year period than those who had not participated in a weight-loss program, she said.
>Another study, which examined a variety of lifestyle factors and their relationship to changes in weight in more than 19,000 healthy older men over a four-year period, found that “one of the best predictors of weight gain over the four years was having lost weight on a diet at some point during the years before the study started,” Tomiyama said. In several studies, people in control groups who did not diet were not that much worse off — and in many cases were better off — than those who did diet, she said.