Well, it is not me, it is some studies. But I'm sorry I can't google them right now. But the evidence, not proof, it is this counter intuitive causal relations

Well, it is not me, it is some studies. But I'm sorry I can't google them right now. But the evidence, not proof, it is this counter intuitive causal relationship that if you have more weight (or exercise more), you have more appetite. And altough sounds "easy" to eat less, it is not. Just like it is not easy to skip sleep. Your body want this... This explain a few decades of moral judgement of obese people just as being lazy, not having enough strong will and stuff. It is just that is not that easy to make people sustainably eat less calories for long periods of time. Not because of character, but because your body and mind have tricks that are stronger than any rationale.