In bodybuilding people do this thing they call "bulking and cutting" where they allow for a lot of fat gain during "off-season" because they think it will allow them to build more muscle. Then they plan their cutting phase such that they will be as lean as possible and often also dehydrated for their show.
In gymnastics there would be a few problems associated with doing bulking and cutting. Firstly being too fat makes gymnastics even harder than it already is. Secondly, gymnastics is about performance rather than looks, and being absolutely bone dry will negatively affect performance. Carrying no fat and being dehydrated will drop your body's weight, but that is not an advantage if it means you're feeling weak and can faint any moment.
So the question is what do gymnasts do with their diets and body-fat levels in respectively off season and when close to competition?
If you don't have an exact answer, at the very least note a range of body-fat percentages.