If you need nutritional information most of the fast food websites have it available to you.
Chick-fil-A is a good example.
Chick-fil-A Nutritional Information
You can find out either the straight nutritional information, or the diabetic exchanges.
If you go to a CDE Dietician, they will give you a sheet that tells you how many servings of carbs, protein, etc. Then you can use these websites to figure out how that will fit in a meal.