I would like to back that up. I used to be the guy that ordered miltiple additional portions of fries all the time. I thought I really liked fries.
Eventually I figured out it was the sugar filled ketchup that was doing it to me. Now I eat fries without ketchup and do not usually order additional portions (unless I am really hungry). Best of all, I do not feel like I am starving myself. When I do not have ketchup, I do not get the desire to eat more.