K L Going 
Fat Kid Rules The World [EPUB ebook] 

When Troy (a hugely overweight social leper) befriends Curt (a skinny homeless punk guitar genius), they both get much more than they bargained for. Troy’s macho brother and ex-Marine father think Curt is just a junkie loser — but as Curt stopped Troy’s suicide attempt, Troy can’t just forget him. Curt recruits Troy as the new drummer in his punk band — but Troy has never played the drums in his life. When Curt’s around, though, almost anything seems possible. An outstanding, heart-warming, funny, edgy, debut novel.