"Cook. Simply by starting to cook again, you declare your independence from the culture of fast food. As soon as you cook, you start thinking about ingredients, you start thinking about plants and animals, and not the microwave, and you will find that your diet, just by that one simple act, is greatly improved." ~ Michael Pollan
I once interviewed for a job as a strength and conditioning coach at a college.
One of the interview questions was about how I'd monitor athletes' nutrition. Their last strength and conditioning coach had gone to the dining halls and marked in green labels what was "good" to eat, and in red what was "bad" to eat. But I wouldn't have felt comfortable imparting my views like that.
If you ask a person who's "gluten-free" what's good to eat, you're going to get a very different answer than if you ask an Italian grandmother who makes pasta from scratch. If you ask a vegetarian what's good to eat, you'll get a very different answer than from someone who self-identifies as "Paleo."
But "what to eat" is less important than taking responsibility for eating. And the best way to take responsibility for eating (besides becoming a farmer) is by cooking.
By the time she's a senior, if an athlete has had the experience of walking into a grocery store, thinking of what to make for dinner, and cooking for herself, she'll have set herself up for a healthy life.
Sure, give guidelines about how to eat in the dining hall. Better yet, get them out of the dining hall altogether.