I've got 24 food coming into a city a week, no troops anywhere around, 0 food to feed the garrison and the food stays at 0/650 for the whole season of summer. I'm watching the ox carts leave from the farm and make it to the city, no food is going from the city to anywhere else

idk whats going on, seems broken

The supply radius is slightly larger than the golden ring around the city that is displayed. Perhaps you have troops just outside this golden ring that perhaps even share their supply with a larger force (the 'food needed' number does not take into account the troops within supply range).
On the other hand the problem could be a larger force in a neighbouring city that cannot be fed with the other city's grain production. If another city is starving, even cities with very low food will give away their last supplies as long as the city is empty.

thanks fellas, pretty sure the problem was I had men sitting right outside the circle radius because I thought that they wouldn't take the food and that was exactly what they were doing. I moved them farther away and it's fine now