First off, the most important thing I can tell you: DON'T DIET! Diets don't work. By labeling foods as 'off-limits' or 'bad', it simply sets up for future purging. You'll have a small piece and feel guilty about it and wind up hating yourself. By denying yourself, you say that you're not good enough, and that's just not true.
Normal Eating is eating when you're hungry, not when you're sad, loney, or mad. If you eat when you're in a negatie state, you'll only feel worse, and could possible wind up binging on food. Which leads to purging. Normal eating is eating exactly what you want when you're hungry for it. Listen to your body. It might tell you it wants a cookie or a burger; it might even want broccoli. It will tell you when it is satiated.
If you want to get a better idea, eat with friends (non-dieting friends), and model your eating after theirs. Enjoy your food and spending time with people at mealtimes.
You may under-eat at times, you may over-eat others. The important thing to remember is that you can trust your body to make up for the difference.