Well our bodies are all different so you may be running out of energy after an hour or so on the bike.

Just remember to eat some carb-rich foods before and after you ride. I started doing this and the difference is night and day. I can stay on the bike for twice as long as I could without properly fueling myself. I don't know how you eat, but I can say that if you really want to get results and maintain good physical fitness you need to be willing to make a lifestyle change. I no longer eat any junk foods like chips, cookies (except for when I go to Chicago to spend Thanksgiving with the relatives ), cake, ice cream, etc. I have stuck to this and kept up riding every day and I feel very good and am dropping body fat and gaining muscle.