A lot, I'd say. Eating before bed is one of the worst things you can do if you're trying to lose weight. Don't eat after six, seven o'clock, and you will do MUCH better with weight control. The thing is, most calories should be consumed at breakfast, then less with lunch and even less with dinner. You have all day to burn off the caloric intake of the bigger meals earlier on. That meal before bed is stuck with you.