I signed up for a few marathons in my area. When I don't have the energy or the motivation to get up and get started, I know that I have to and it keeps me going.
I don't eat anything after 8:00 p.m. not even a snack. Now I'm hungry enough in the morning to eat breakfast (not just coffee) .
When I don't get a lot of sleep or don't have enough energy to do anything I log on to SP. No matter how tired I am or how I feel I always seem to get up and get going after logging on to the sight.