Simply, there are two kinds of foods: food made for our senses, and food our senses were made for. Our brains evolved so that we find pleasure in food that are nutritional to us, according to its availability in nature - and we're made to stop eating when we have eaten enough. Our bodies were not designed to overeat. Except that it didn't imagine that we can ever manage to hack nature so much that we can live without exercising, and that we can hack our food so much that our brains can no longer tell the nutritional value of food.