They use approximate network location for such requests, yes.

"chinese food" didn't trigger it for me which is understandable since it's a generic term, not a request to show chinese food restaurants near you but "chinese food near me" does show restaurants in my approximate vicinity as expected aswell as localised search results for tripadvisor.

In their privacy policy they claim that that's explicitly the only time they use data that could be considered sensitive in a search request.