The ability to feast at your settlement and gain buffs is cool, but it should also fill your rations. Rations are filled by collecting foods, and a feast is a meal with ample amounts of food, so it would make sense to have it fill up the Eivor's rations. It doesn't make sense that I have to go gather berries and food immediately after a feast just to make sure I'm stocked up.
A bonus idea would be for the feast to give Eivor a temporary ration over their allotted max, so you have extra to take with you out into the world. Once you use it, the bonus one is gone and cannot be regained except through another feast.