Instead of having 3 large meals a day, try having about six smaller meals. Frequent snacking will keep your metabolism going, and keep your energy levels up all day. Keep food with you when you are out for a few hours so that you won't be tempted to stop for fast food. Food like granola bars, trail mix, and fruit are easy to keep with you and snack on when you are busy. Ensuring that you balance out your calories throughout your day will also help prevent over-eating at night.