A possible concise summary is:
Junior wants to impress a new girl in his class who likes Cody's body. He tries to get a six-pack, a big hot dog, and money, but fails. He calls a doctor who tells him to do whatever Cody does. Cody sings a song to motivate Junior to work out. Junior gets the same body as Cody, but the girl rejects him because she likes Cody's pizza face.
Here are some possible facts extracted from the text:
1. Cody has a six-pack and Penelope likes him for that.
2. Junior wants to look like Cody to impress Penelope.
3. Mr. Chu teaches the class about the laws of attraction.
4. Junior tries to get a big hot dog, money, and steroids to look more attractive.
5. Cody makes a song to teach Junior how to get hunky.
6. Penelope likes Cody because his face looks like pizza.