No, the best Gymnasts are not short due to eating disorders. The best Gymnasts are short because height/length is the limiting factor in rotational momentum/energy. May an elite gymnast end up shorter than their genetics dictate, maybe, like an inch at max. The vast majority have very well developed muscular structure that would lead to an increase in height. The more important factor is stress. You often hear about gymnasts not having periods or not reaching puberty till they are like 17, stress hormones are often the cause. You will very often see gymnasts quitting the sport, and then ballooning. Nutrition was never the problem. They are liking like they used to, but not getting the same excercise.