Unfortunately, Disney doesn't have any accurate nutritional information available. To quote their website, "Unfortunately we do not have, and therefore we cannot provide you with accurate or reliable nutritional information, and we would not want you or any other Guest to rely on what could only be our "best guess." We can however, attempt to work within your dietary request and suggest some menu alternatives and solutions that may satisfy your requests. We strive to provide all our Guests a magical experience by offering a wide array of dining locations, experiences and menu options, and we trust that among all those selections you will find menu items that meet your requests."
Searching around for the information has yielded very little in the way of actual results as well. however, you may want to check out
Eating Healthy(ier) at Walt Disney World [Eating on Vacation], it has some stats that may help!
I guess Disney wants people to spend their time, and money, not worrying about their intake. It is a vacation, but it sure would be nice if some of the more common items, that don't change very often, were made available.