I found this statement with the list of prohibited substances (a very long list) I would suggest you google to get the list and then check the ingredients of the "snacks" to be sure they don't contain any of the prohibited items.
We had the same request last year. The link is a long one, so I've included both the link and part of the list of approved snacks. The key is the snacks have to be low fat and low sugar.
http://www.ncaa.org/wps/portal/ncaa...on-performance/student-athlete/nutrition.html
The key is little or no processed sugar. At parents weekend our DS described soda as tasting like the tears of god. I think, he increased his grasp on self control.