Interesting. Apparently the criticism is that he never swallows. But I did a quick search and found this: https://www.wired.com/story/this-streamer-has-convinced-the-internet-guy-fieri-never-swallows-food-on-diners-driveins-dives/

As critics of the conspiracy theory were quick to point out, some of this sleight-of-fork is to be expected in the production of DDD. Fieri visits lots of restaurants in a short span of time and can’t eat full meals at all of them. Sometimes a second or third (or tenth) take is necessary, and it’s not practical to take a new bite for each. Certain editing choices are no doubt for the sake of continuity and flow: does the audience really want or need those few extra seconds of awkward silence as Fieri finishes chewing a morsel of barbecued meat and gulps it down?

Others simply disputed the accusation that Fieri is faking it. “Not true,” Joe Sasto, a chef who has competed on a Food Network Tournament of Champions series hosted by Fieri, commented on the Doctor Spaghetti video that ignited the no-swallow controversy. “I’ve filmed plenty of shows with him. He eats EVERYTHING.”