In Feed the People! @gnrosenberg.bsky.social & I make a similar point: there is a vast gulf between food availability (is there food?) and food access (are there resources to get food?) and utilization (is food made nutritious?). The food desert idea - especially applied to cities - conflates these.
"There is little evidence to support the idea that bringing supermarkets to neighborhoods that lack them has a measurable effect on what residents eat."