It all comes down to calories in vs calories burned.
You can eat 1,000,000 calories a day.
If you burn off 1,000,000 through exercise and basic day-to-day shit then you break even.
If you burn off less then you gain weight.
If you burn off more then you lose weight.
3500-4000 cals =s 1 lb body fat.
Basic weight loss 101.