I can personally debunk his, "Super-Size-Me," theory with my diet.
Basically, McDonald's super-sized meals are never enough for me and haven't been for years. Yet to this day I'm still between 180-185 pounds at six-feet tall.
I have the dietary needs of a tiger.
Welcome to FR.
Metabolism is an amazinging thing. I had lunch with a coworker, a girl about 5'1" and an avid runner (I'm 6'3".) We both had these massive Italian subs with pasta salad on the side. On the ride back to the office, I was ready for a nap to relieve the incredibly stuffed feeling I had.
She had me pull into a drive-through on the way so she could get a 32oz chocolate milkshake - I couldn't believe it!