Fad diets come and go and come again. The cabbage-soup diet, the low-carb diet, the glycemic-index diet, and others all cycle in and out of popularity. But stunt diets--crazy, funny, extreme food feats--are more rare. From the professor who ate nothing but junk food for a month to the guy still trying to live on nothing but potatoes, these diets have less to do with losing weight than with proving a point. Read on for the most memorable stunt diets.