Despite what the commercials want you to believe smaller is better. I'm of course talking about portion sizes. It's really the key to losing weight and allowing your body to properly use the energy it's receiving. When you over eat your body doesn't have a chance to absorb all the nutrients you've just taken in, also your body takes the excess carbohydrates and sugars and stores then as fatty tissue when you over indulge.
To lose weight and feel better, eat smaller meals but more of them. The key for me is preparing food ahead of time then eating (a protein about the size of your palm, and a carb/fruit/vegitable about the size of your fist). Then wait a half hour to see if you're actually still hungry, you'll find 9/10 times that you aren't and that if you are a full glass of water will curtail that.