Linda
Yes there are. You won't be disappointed.
Toruko
Absolutely. On arrival see the Yellow Pages of a Telephone Directory.
If in doubt dial the county health department for advisement.
Sharon
the best eating in Yellowstone according to the local bears is humans
Anonymous
No. Any concessions are crappy, crowded and horribly overpriced.
Pack your own food.
There is a regular grocery store in West Yellowstone. There is also a grocery store in Cody, but that is quite a trek unless you're staying there. I can't remember if there is a grocery store in Mammoth or not. We avoided Mammoth like the plague. Too many people.
W.T. Door
Tripadvisor:
https://www.tripadvisor.com/Restaurants-g60999-Yellowstone_National_Park_Wyoming.html
NPS:
https://www.nps.gov/yell/planyourvisit/wheretoeat.htm
Yellowstone Park:
https://www.yellowstonepark.com/where-to-stay-camp-eat/restaurants-grocery-inside-yellowstone