I Don't Buy Kisses Anymore(1992)

Bernie Fishbine is overweight. He stops at the neighborhood store to buy some chocolate kisses every day. This is where he meets Theresa Garabaldi. Then they take the same bus route every evening. Theresa invites Bernie to see her play piano at her father's restaurant. It is here that she gets him to join a gym. Theresa is in college and gets the idea to write about Bernie's weight problem for her thesis. She does this without telling Bernie. Meanwhile, Bernie is falling in love with Theresa, and vice versa.