I guess I’ve just not heard of the term ‘food desert’ used to describe a lack of healthy food and not…… a lack of food period.

you probably have but maybe just didn't realise it, since that's what it means:

A food desert is an area that has limited access to affordable and nutritious food.[1][2][3] In contrast, an area with greater access to supermarkets and vegetable shops with fresh foods may be called a food oasis.[4] The designation considers the type and the quality of food available to the population, in addition to the accessibility of the food through the size and the proximity of the food stores.[5]

https://en.wikipedia.org/wiki/Food_desert