OFA heightened all of Izuku's senses, and after losing the quirk the senses didn't entirely fade.

It's not like he can hear an ant coughing from a mile away, but he has really good hearing and peripheral vision, and his reflexes are incredible.

The big problem is that his tastebuds are still hyper-attuned, apparently his brain got so used to it that when OFA left his sense of taste stayed exactly as powerful as before. Izuku now has an incredible appreciation for fine, gourmet dining.

So naturally he gets lunch rush to tutor him.