Well, as I write this, it's 1:45 AM, I'm dead tired, and was supposed to go to the gym tomorrow morning, but instead of sleeping I'm sitting up with a squirming 14 month old who keeps farting himself awake because, despite my best efforts to feed him a balanced diet, he eats nothing but bread and dairy. So, I'd say my biggest contributing factor to weight gain is, "insomnia-induced lethargy caused by baby farts."