"What if... Our stomach and digestive systems are normal? It's just our brains thinking we're hungry, like underweight or under eaters; their brain tricks them into eating less and small portions which makes them skinny, and for Heavy Eaters; they eat more and eat larger portions of food because their brain tricks them into thinking they need to eat more so they can be full.... So the brain can make the digestive system either suffer or make it too lazy. It could also be the reason why we get fat; if we eat too fast or too much that it exhausts the digestive system, it makes it slower to digest it and therefore larger junk foods expands the belly or possibly make it wider. Which is the reason why there is so many obese individuals nowadays, and our brain keeps making us eat less or eat more and faster so we get fatter."