The quantity, quality and all out availability from food banks and churches vary. The one near me took days to finally get an appointment. I had made a meal from some of the assortment and dutifully figured the mixed vegetables from a can (generic and probably expired) would have nutrition, right? Well something wasn't right because I yakked up the entire meal afterwards. I can still taste the can in my mind to this day. Some of the offerings were terrible enough that you are lucky enough to get the basic caloric input and keep it in.
I know this can sound condescending but many folks have been in a bad place income-wise. Or just during times, school, camping, etc where stores are far between. And there, providing mobility, you find much more value in cheap stuff with nutrition. BEANS, RICE, SARDINES. Cheap, portable. Fiber, protein, and filling. And you can buy in bulk cheaper, if one has place, even a cheap studio apt or dorm room or campsite, to soak beans overnight before boiling them up. Ramen, pasta, etc is, sorta worthless, except for salt or "filling" naturet. Though I've known some that swore by sacks of potatoes. But really, much of the world SURVIVES on some staples. No reason why someone can't do for some years, in a pinch here. And if supplemented with good protein like sardines? You'll be good. More importantly though is clean water and lots of it. And don't ignore hygiene. Teeth/Mouth firstly and body second.
