The poor don't get many options. Ever been to a food bank in America? It depends a bit on each bank but 99/100 you are going to get more carbs than veggies. You almost always get one or two boxes of sugary cereal crap, one loaf of bread, and a mountain of pasta since it never goes bad.
If you do get veggies they are likely rejects no one else wanted to buy. If you are lucky they are just ugly. If you are unlucky they are already starting to go and you have to cut around rot and eat them in a couple days. You will likely get canned veggies that are unpopular like cannelloni beans or something. If it's frozen veggies they are likely frost burned to the point of barely being edible.
Whenever we have hit a tough patch and needed help from a food bank we gained weight and feel like shit. Meanwhile the best diet that ever worked for me (keto) required fresh veggies and plenty of butter (or other fats), eggs, and meat. It isn't cheap when you are broke and you really have no choice. It's a societal issue, just knowing what is right yourself won't help if everyone else is ignorant.