I've found that external motivation and internal motivation parallel each other very distinctly. It wasn't until I was super fat and then found out that I hated all fat people that I truly began the steps to reaching my healthy weight. The "fake it until you make it" phrase is kind of true in this sense. Exercise is more of a hill than a mountain. After you get over the initial difficulty, moving forwards gradually gets less difficult. A heavy dose of reality isn't a bad thing either; waking up to the fact that everyone hates fatties and that they're Zombieland's first to go is a good starting point.