Majority of people do not even realize that obesity is bordering on the lines of disability. Most often being overweight is as a result of incapacitation. Overweight is a direct result of damaged communication between the body and the brain. To some overweight individuals, the reward is in the food at all times from beginning to when the last piece of the food is eaten. Any more food brought immediately will still have the same reward.
Unlike overweight people, normal sized persons have no desire for food reward after their belly is full. Their brain tells them to stop eating. Any attempt to eat more is totally unrewarded.