I know exactly how you feel. I've cried in the past, wailing, "Why can't I just eat what I want like other people?" Sounds so incredibly immature and whiny to me... that's how I felt though.
Whenever feelings like that rear their ugly head, I turn "Why can't I eat what I want? It's not fair!" into "Why would I WANT to eat all that stuff? I'm better than that." Focusing on the power to choose works for me. (Most of the time.)
Keep on keepin' on.