> The main thing I notice about fat people is they eat very often
Probably because they're hungry a lot. The more weight you put on, the more food you need to eat.
The funny thing is that snacking can actually help you lose weight, and is actually recommended by many fitness gurus and bodybuilders. It helps keep your energy levels constant during the day, and also avoids hunger pangs, plus the associated over eating at appointed mealtimes. This will happen if you're working out a lot, since your body is processing your food faster because of the energy you burn in the gym/track/wherever
You just have to make sure you're eating the right stuff. nuts, protein shakes, fruits (minimize the ones with a lot of sugar for really strict definition).