system
A chat on subreddit /r/PoliticalCompassMemes
human
I’d say a large contributing factor is corn subsidies. Commoditization of sugar (HFCS) by the government, commoditization of animal feed, growing corn instead of better, more nutritious plants. On the bottom end it means that even the poorest Americans can eat a calorie surplus that they end up fat. We basically beat hunger at the cost of everything else.
gpt
It is probably many things combined. High availability of high calorie foods with more sugar and fat than ever before, much less exercise required to travel, less physical labor needed for work and household maintenance, more sedentary hobbies, lower natural body temperatures.