I only emphasize healthy eating and regular meals/rest.
I had a well-meaning coach use my DD's lunch as a visual device during a camp seminar on nutrition. She was my DD's coach at the time and she felt comfortable using her as an example, but it backfired. For the first 3 days of the camp, my kids went with fresh fruit, water/juice and a salad or sandwich on whole grain bread. On the fourth day, I send a sandwich made with potato-wheat bread that I wanted to use up before it spoiled. Did the coach mention the healthier choices earlier in the week? Nah, she just made that day's lunch an example of "what not to eat."
The coach meant to say "Eat whole grain breads," but DD heard "don't eat sandwiches. Ever."
Her lunch came home, unopened and uneaten, for the rest of the camp. She wouldn't even open her lunch bag or eat food where the coach could see her, for fear of being singled out again. She told the counselors that she had a stomach ache and starved herself, drinking only water, until pickup. Then, she wolfed down every piece of junk food she could find at home, even secreting some it so I wouldn't catch her eating chips again.
After many discussions, she finally understood the real intent, and she pointed out that the coach didn't say anything about another coach's skater eating artificial nacho cheese & chips for lunch, roflol! I guess the coach didn't care about that skater as much. (I say, tongue-in-cheek.)
So, coaches, don't ever single a child out for not eating the correct things, especially when they're eating!
I stopped a skater from ordering nachos (same kid, different event) while she was wearing her synchro costume and waiting to compete! That was different - I didn't want her to get in trouble with the synchro coaches (who don't handle stress well in the first place) for spilling it on her dress or eating the wrong thing before the event.