S02E17 He's Too Sexy for His Fat
After suffering endless teasing and humiliation about his weight, Chris decides he wants to shape up. Peter puts him on a diet and exercise program, but when the results are slow in coming, he turns to plastic surgery. Chris opts out of the operation at the last minute, but Peter decides to have the procedure done himself, followed by implants and reconstruction that turn him into a self-centered hunk. Meanwhile, Stewie tries to taunt Chris by overeating, but ends up with a weight problem of his own.