The first 50 pages and the last 100 pages were interesting (the movie seemed to be based off of these sections of the book). 
 The remaining 150 pages, however... were extremely boring and moved at an unbearably slow pace. It consisted of repetitive scenes of Pat working out in his basement, Pat running while Tiffany followed, Pat reading (and spoiling) a classic novel, Pat watching football, Pat talking about football, Pat talking to his therapist, Pat working out in his basement again, Pat going out for a run again, and so on. I think this cycle went on for about five or six times before things finally became more interesting, and the story was finally going somewhere.