We get hungry when our stomach tells our brain that it's nearly empty. But signals from our stomach can leave us vulnerable to overeating.

Fullness is determined partly by the fat, carbohydrate, and protein content of the meal, and partly by the overall amount. If a meal contains more fiber, it's more filling. That is why it is hard to overeat on foods such as fruits and vegetables.

We can consume more foods with a higher energy density, like pizza, chocolate, and chips, than the same amount of food with a lower energy density, such as apples.

We're prone to overeat high-calorie foods because they're less filling per calorie and more pleasurable to eat. With repetition, you may find yourself choosing the lower calorie option and keeping your weight in check.

It is hard to resist our desire to eat higher energy-dense foods, making dieting lapses inevitable. Motivation to maintain the diet may dwindle and can add to the perception that the last five pounds are harder to lose.

Our weight will settle around a point that is a balance between the desire for certain foods, our ability to keep our eating in check, and the energy we expend in physical activity.