I eat a lot, because I bike everywhere. A couple hundred KMs/week, usually topped off with one big ride per week (100+ KM sprint with the racing team).
I also hit the gym at least 3x/week. Abs everyday, one day chest/tri, one day back/biceps, last day shoulders, legs, traps, and all the other little random muscles.
I try to switch up my routine when possible. However, I love the inclined bench, military press, deadlifts, squats, and flys.
Although my routine may not be the most effective routine ever, I like it, and that's most important to me. I'm seeing improvements in strength and physique, so meh.
It's really not rocket science. You eat, you lift, you gain. You eat less, you lift, you lose (fat).