Here is my opinion on the food at my 2 main home zoos here is Southern California
The food at the Santa Ana Zoo at Prentice Park is pretty good, they only have one restaurant and it is called Knowlwood Cafe at the Zoo (They also have 1 other location separate from the zoo across town), IMO Knowlwood tastes better then the zoo's old restaurant which was a restaurant called Los Pearles Amazonas or something, at the old restaurant the american food was horrible but the mexican food was alright. Back when Los Pearles was around, I was a vegetarian so I ordered Cheese enchiladas with rice and beans, but now that I am a non-vegetarian, at Knowlwood I usually order a Turkey burger with cheese or Chicken strips with ranch dressing, both meals I order with french fries and a large pepsi.
Now for the Los Angeles Zoo, It depends on the restaurant or food stand, the zoo has 8 or so restaurants and food stands, Reggie's Bistro is pretty good, when I eat there I usually order a grilled cheese sandwich with french fries, the other food places are just ok and the one closest to the Children's zoo is called Zoo Grill and they serve pretty much the same food as the food place across from the Okapi/Black duiker, Giraffe, Common chimpanzee, and old African lion exhibits, both places serve food like Hot dogs, Grilled chicken sandwiches, Chicken strips, Cheeseburgers and food of that sort. The food place across from the Western lowland gorillas, Grevys zebras, Desert bighorn sheep and other animal species in that area is called the Gorilla Grill and the food there is somewhat different from the food places near the Children's zoo and Giraffe exhibit, the food at Gorilla grill consists of Philly cheese steaks, Sausage sandwiches, Onion rings and a few other things, there is also a place called Cafe Pico which is in the South American section and they serve mexican food like Tortas, Burritos, Tacos, Quesadillas and stuff of that sort. There are other food stands at the Los Angeles Zoo that mostly serve snacks, but much of the time on my trips to the Los Angeles Zoo, I eat across the street at the Gene Autry Museum of Western Heritage, they have a cafeteria with food that is really good but over-priced, when I am there usually order a grilled vegetable quesadilla (They want 11 dollars for it).