The dietitian at the office says that including protein with all your meals and snacks helps control blood sugar. I have tried it and it seems to keep my energy level more stable... which is great! If you eat just fruit, for example, she says your blood sugar goes up, and then your body produces insulin to lower it, and then it may be too low and you feel like low energy... she says combining with protein prevents that.
For example, don't have just fruit as a snack... always have some almonds, yogurt, cottage cheese, peanut butter, or a cheese stick with your fruit. A few days ago I tried grapes with peanut butter and I absolutely loved it.