Hmm... diets... I'm too young to undergo one. But sometimes I do some cutting down of what I eat and control of what comes in my stomach LOL.
Usually, I eat moderately at breakfast, then chow it down at lunch. I avoid fastfood as much as I can (yet it's a bit unavoidable); I eat nuts instead (contains good cholesterol) or maybe some fruit shakes and some cereal drinks. I also drink this fiber stuff called C-Lium along with my noon fruit juice; it kinda controls bowel movement and it also helps on you weight.
I skip dinner usually. It will not also just cause you more uhh fats but also makes you feel more tired at morning. Don't make me explain it. If I eat dinner though, I eat some whole-wheat tuna sandwich complete with a yummy non-fat mayo
It also helps if you cook the food yourself

That way, you'll be sure that it doesn't contain artificial preservatives or too much oil. I remember when we had some beef soup, it was way too oily, so I refrigerated it so that the oil will go on top, harden, and that way I can remove the oil.
And I never cut down rice or bread. Maybe it's just me being a kid, but it feels a bit better if I eat along with it... at least in the morning. At noon, I'm trying to cut it down XD