I'll second what mahyarm said about being aware of calories.

Download Myfitnesspal (or bookmark the website) and use it for one week.

I'll disagree with mahyarm about needing anything fancly like liquid egg whites. For most people substituting water for softdrinks will make a substantial difference to the calories. Carrot sticks do make a good snack though (they have a high satability index). Pears are also good if you prefer something sweeter.