Food, Girls, and Other Things I Can't Have by Allen Zadoff

Andrew is fat.  Really, like over 300 lbs fat as an underclassman.  So he's used to trying to not stand out and sticking with his smart kid status in high school.  But then he falls in love with a new girl who instantly shoots to the top of the social scale and Andrew feels like he has to compete.  She tries out for cheerleading, so Andrew decides to try football instead of the Model UN team. He's massive, and his asthma causes some problems, but he's determined to make April notice him.  Andrew likes the positive attention of the football team, too.

This book is a great example of guy lit--a YA Nick Hornby.  It also won the 2010 Sid Fleischman Humor Award, so I'm not just making things up!