The Kabocha Wine

The Kabocha Wine, also sometimes referred to as The Pumpkin Wine, is a romantic comedy manga written and illustrated by Mitsuru Miura and serialized in 1981. It follows the relationship of high school students Shunsuke Aoba and Natsumi Asaoka (who goes by the nickname Eru), who have a very glaring difference in height with Shunsuke being notably short and Eru being notably tall. In 1982, it was adapted into a a 95-episode anime by Toei Animation.

Anime

E02

Shunsuke is seen still eating after everyone else has left, stuffing himself for the night.

E07

Shunsuke enters a challenge to eat a large bowl of anmitsu for money to buy a birthday present for Eru (who happens to share the same birthdate as him), ironically, at Eru's family restaurant. Once he figures that out, he tries to quit mid-challenge but his dormmates force feed the rest of the dessert to him, causing him to win.