Humans evolved to want to eat all the time because our ancestors never had enough food. Eating patterns are engrained human genes, but there is disconnect between why our population is obese and our ancestors were not. The natural food our ancestors used to eat were not calorically dense and the processed foods of today are.
So how do we fight our natural urge to eat all the time? How do we fight genetics? We can, but we do not. America as a whole does not limit portion sizes. The culture of fear that has developed in the US contributes to the stress response. Eating is an addiction Americans can feed cheaply, building a tolerance to the sweetness of food at the same time. People can justify spending more money on quantity rather than quality because the least healthy calories are the cheapest calories to purchase.
Eat natural, unprocessed foods.