Even much shorter fasts help you to understand how unimportant and fleeting a lot of feelings of hunger are. You get hunger pangs and feel like you need to eat, but in a hour it has passed and you go another 8+ hours just fine. When I eat some crappy food, I know it is going to make me feel very hungry in a few hours, but when it happens, I know it isn’t a real need and it helps stop the cycle of bad eating/overeating.
I'm not religious at all, but I still sometimes practice Ramadan for this reason. On top of the communal experiences of charity and shared meals that are more present during the month, the reminder that my body is greedy for food and does not really need so much is such a good annual reminder to have.
