The nicest way that i can put it is that this has been true for most of human history until industrialization, let’s say that the 50’s is when industrial food starts to make poor people fat.

The less nice way to put it is that this hasn’t been true for 70 years. You are completely clueless to health food and poverty in the 20th century, let alone the 21st. Nowadays, eating nothing but the cheapest food will in fact make you fat.