What you eat in the two hours prior to bedtime has an enormous impact on your physique, especially when it comes to fat loss. Here's the rule:
Eat for what you're about to do.
Most of us aren't going to move around much during the two hours before hitting the sack. For that reason, we don't need to eat a traditional bodybuilding meal at that time. Instead, we need to eat for what we're about to do: not move very much.
More specifically, your carbohydrate needs are dramatically diminished when you're sleeping. Remember, carbs fuel high-intensity exercise like weight training and sprinting, and there's no such thing as "high-intensity sleeping."
Fat, on the other hand, becomes the primary fuel source as the intensity of exercise goes down. In fact, when you're sleeping you're burning almost exclusively fat for fuel. Therefore, feeding your body carbs prior to bed dramatically increases the chance that the carbs are stored as opposed to being burned. And if carbs aren't burned, they're either stored as glycogen or as fat.
What If I Lift at Night?
If you happen to have weight-trained (cardio doesn't count) in the last three or four hours prior to going to bed, then there's very little chance that the carbs you eat at this time will be converted to fat. That's because glycogen stores are low and will hog all the carbs, leaving none needing to be converted to fat.
But for those of us who don't train within three or four hours before bed, we should minimize carbs in our pre-bed meal if the main goal is fat loss. (Don't be afraid of low-starch veggies at this time though.)
The Fat Factor
As for pre-bed fat intake, I stand by the rule of "have fat when you don't have carbs." However, cut your normal portion of fat in half, so for the last meal of the day, limit yourself to 10 or 15 grams of fat.