Well, the most popular solution is to go on a diet. Unfortunately, that's not always the best solution. What works for me is to change my lifestyle to fit my diet, vice-versa, or a little of both. If you eat a lot, be more active. Or if you decide to eat less, then only eat as much as you need, not as much as you want. Being hungry doesn't always mean that you need food. Sometimes it's just because your stomach isn't as full as it'd like to be. Put simply: match the energy you use to the energy you take in. In your case you'll have to catch up to how much energy you've taken in. But make sure that you get active and stay active. The body won't necessarily take the energy from fat cells first; it will also break down muscle cells that the body isn't using, sometimes before fat cells.