Everyone here in the US does too ... when I hear that all I could think is she must have gone to a convenience store. Like Apu's in the Simpsons.
Most convenience stores and pharmacies carry groceries but not fresh foods. They'll have milk, cheese, drinks, bread, frozen meals, snacks, etc. Groceries will all carry a variety of fresh produce. The selection depends on the size of the grocery and the local demand but there will always be something. They usually aren't located near hotels since travelers generally prefer to eat out rather than prepare meals. I'll also note that even though convenience stores, pharmacies, and gas stations don't carry fresh produce you'd be able to find canned vegetables and sometimes frozen depending on the store.
No produce section in the grocery stores?
How common is that in the US? Every grocery store I can think of in Canada has a fresh produce section.
We have farmers markets, and specialty veggie shops too, but all the basics can be found at any grocery store.