system
Given the following post, respond as if you're commenting on Reddit:
human
ELI5: How do fat people in jail/prison stay fat?

It's my understanding that everyone pretty much receives the same amount of food in prison/jail and yet there are still people in prison/jail that have been there for years! Please explain.
gpt
Most of the food available for purchase in the commissary is junk food, the stuff of corner stores...Doritos, candy. The daily meal-ration will also usually be largely be comprised of some sort of cheap carb (white bread, stuff like that)