Have you been keeping an eye on your carb intake? All carbs convert to sugar in your body, including the complex carbs although they convert much slower than the refined carbs. Bananas are very high in carbs, fruit in general has quite a lot of carbs mostly in the form of naturally occurring sugars, but again...sugar!
If you are using fitday, don't let your carb ratio go above 40% of your calorie intake. Another thing is to cut down on the crystal light, I know it is so much better than plain water but some studies have suggested that your body will react to the artificial sweeteners like they do to sugar, so even though you aren't adding calories, your body will have an insulin reaction to the aspertame.
Another idea is to eat more calories in the early part of your day, and less towards the end...meaning make your breakfast and lunch your biggest meals, and keep dinner light and avoid carbs in your evening snack.
Remember to drink a lot of water all thru your day.