My dd will home from practice and eats 2 PB&Js as a pre-dinner snack. Whole wheat bread, natural PB and jelly. And SO disgusting! But, look who's a bit chunky sitting around on the couch, and look who has Abs of Steel...what do I know?
Our coach occasionally sends home nutritional sheets, more to make sure they are eating enough than to offer firm recommendations. I don't prefer this communication because I don't think it's their place, but I have the luxury of being able to either take from it what I find useful or ignore it as I see fit because my dd is healthy and overall makes pretty good choices. I would be quite a bit more upset if we had extenuating circumstances. I think that the coaches at minimum should be saying "these are my recommendations. Please discuss with your parents at home".
IMHO teaching our kids to listen to their own bodies and feed it accordingly is the number one goal. Everyone has different paths to help their kids get there.