When we rely solely on willpower as a driving force, we often drain our reserves, making us susceptible to failure. In the words of social psychologist Roy Baumeister: "willpower is like a muscle, becoming fatigued from overuse". However, he goes on: "(it) can also be strengthened over the long-term from exercise".
There is no doubt that willpower is an important first step for change. It's about having the ability to care about what you are doing - you know the old chestnut, "where there's a will, there's a way".
The reality is, where there's a will, there really is only a will. It's an important first step, but it's not enough. To blame a failed diet on willpower is ignoring the complex interaction of brain chemicals, behavioural conditioning, hormones, heredity and the powerful influence of habits. We can't simply tell an overweight person to have more will, just like we can't tell a depressed person to 'snap out of it'.
Preventative medicine expert David Katz says: "You have to be empowered before you can take responsibility. Otherwise, you may have the will but lack the way. That's a formula for serious frustration and a set up for failure".