In the case of something like a world war, which is the type of scenario we're talking about here, I think people would begrudgingly accept that bananas and coffee are unavailable or very expensive.

People substitute very quickly and happily.

I remember food shortages during Covid. Nowhere near as bad as toilet paper shortages.

I can go without chocolate for a few days. Weeks, maybe. But if it becomes months, I get crabby.

I'll die before I go without my curvy yellow lumps of mush.

I've heard it usually takes at least an acre to grow enough food to feed a single family.

It depends a bit on your crop mix, yield, and of course, family size.

You'd be surprised how much some crops can yield in small areas. (Oh god, I used to actually like pickles before I realized how many cucumbers we were churning out last year.)

Where it gets space-intensive tend to be grain crops, which we don't currently grow because the ROI is so low, but have space to if life forced it on us. Protein can also be a little tricky depending on what your expectations are, but if you're okay with mostly beans and eggs, you'll be alright on well less than an acre for a small family.

Feeding a family on an acre is a bit like making pencils one at a time.