The food is added to the bin the moment the villagers pick fruit from the trees or pick up the dropped fruit from the ground (after all of the trees have been planted). In order to see the change in the food supply, you need to watch as the fruit is picked. Also, the villagers eat a certain amount of food, even when you don't see any of them at the food bin. If food is eaten at the same time that fruit is picked, you may not see a change in the total food supply. This is normal.
Have more questions? Submit a request