Your body metabolizes the same way at night as it does during the day. If you eat at a calorie deficit, you lose weight. If you eat at a calorie surplus, you gain. With the exception of a lot of sodium or sugar before bed. That would effect your morning weigh in due to fluid retention.
I eat 60% of my calories before bed and lost 60 lbs in 8 months. I have dinner at 8pm and a huge yogurt parfait with peanut butter and Kashi cereal (350-400 cals) at 10:30 pm right before I turn in. If I don't, I wake in the middle of the night hungry and get into things I'd rather not. I also workout in the morning on an empty stomach and have lost fat easily and gained muscle easily. In fact, some body builders swear by it, it's called intermittent fasting or IF.
Let's say you ate a lot of calories before bed and it did store as fat overnight (not sure how long the process takes) because you didn't need that many calories. If you're on a calorie deficit, your body does not have enough energy to function from your food alone. The following day, you would tap into those energy stores (fat) for fuel and still lose weight. Now *if* eating at night causes you to overeat (eat a calorie surplus) by triggering cravings, then you should probably avoid it.
Sumo wrestlers gain weight because they eat more calories than their calorie expenditure and probably do so in their off season, while training they would eat enough to maintain. Just as Michael Phelps needs to eat 10 000 cals/day just to maintain his weight when he's training. Sumo wrestlers would have to make it their job to eat while training.
I was actually quite surprised to see Fitbit Premium trial telling me I shouldn't eat the majority of my calories before bed. It's a myth just like the "fat burning cardio zone". Why would I ever pay $50 for something to give me misinformation?
http://www.webmd.com/diet/features/diet-truth-myth-eating-night-causes-weight-gain
