Earlier quoted context omitted.
The lack of food can be explained either by a shortage of demand or a shortage of supply. Many people assume that the demand is there and the supply is the problem - people are desperate for healthy food but no one wants to sell it to them for some reason (the reason is always left unsaid). Instead, they have no choice but to shop at 7/11. So presumably, as soon as a store selling fresh, nutritious ingredients opens…
Time is extremely scarce for poor people. Cooking healthy and cheap meals means research, planning and batch meal prep. This also requires being a forward-looking state of mind. Personally, I think the government should be investigating ways to raise income levels for the poorest. I don’t know what form this should take - UBI? negative income tax? - but fix that and the rest would follow for many people.
Speaking as an immigrant, from what I've seen in US, it is mostly a cultural issue, not lack of time or ingredient availability.
UBI is a good idea but orthogonal to all this.