As of 2021 at least, there was a McDonald’s (plus a Pizza Hut) at Cleveland Metroparks Zoo.Does any zoo have a McDonald's? I know there's the Starbucks at Saint Louis, and an Erbert and Gerbert's at Minnesota, and I know there's a Chick-fil-A somewhere (Atlanta?).
A few other US with zoos with what could be considered probably high-end dining (as well as more fast-food options) would be ASDM, Shedd, DAK (as well as The Seas at Epcot and the DAK Lodge), the SeaWorld parks, and Grant's Farm. DAK probably has the widest variety of food options at any zoo, ever.