Lack of calories is not an issue in the USA. There are redundant pathways to get the staples people need, food banks, stamps, ect.
The few percent of the population that suffer insecurity do so as a symptom of other complex causes. Children of addicts and mentally unstable will struggle to get dinner, even if there is a food pantry down the block. A homeless schizophrenic living out of a backpack wont always have food with them.
For reasons like this, there is a floor to the practical floor to the elimination of hunger.
Also, if you havent, I would recommend reading through a food insecurity survey if you haven't. The definition is broader than most realize.
If you look at malnutrition rates in the US, I think you get a much clearer picture.