I always ate food in not much large amounts, but one thing that impressed me is that when I switched my diet (when I could afford it...) to salad + cheese and meat, the amount of food I ate dropped a lot, even in unrelated meals.

It was great to go to a restaurant, eat a third of what other people were eating (it was a weight-based restaurant, so I could see that I ate a third of what other people ate, in weight of the food terms), and feel completely satisfied.

Even better, I could get back to work right away, or even go do something that require physical exertion (for example once I was late for something, and could eat, and then immediately run toward the place where I was supposed to go).