@igazor, it is definitely Story Progression, it came up in a discussion previously. I have also been playing an un-modded game to try out some things and found my Sim's fridge full of ingredients when starting a new game, so I tried putting SP back in to check that it is SP that stops that.
@philkewley, your first problem of an overstocked fridge seems to be quite common but like igazor, I don't know why it happens. For me it's always 54 eggs, 15 cheese, 3 each of links lettuce and tofu, which are the original 5 items, then 8 other ingredients, some of them from Bohemian Gardens. I don't switch households though, so can't comment on your other problem. As I normally play with NRaas Story Progression, it doesn't normally bother me.