The ability to keep on working when we want to go play, to study when we want to watch TV, to stay focused on a project when our pop-up emails are screaming at us, to avoid food we’ve sworn off – the list goes on – all of those require control.  Self-control.  Willpower.

Willpower has gotten a lot of psychological press these days, and for good reason. It’s been deemed a required attribute to be more successful and focused. It’s needed to achieve our goals. The great debate centers around whether willpower is a muscle that you exercise and therefore get better at it the more you do it, or whether it’s solely a matter of energy. The answer likely lies somewhere in between.

Matthew Gailliot, Roy Baumeister, and their colleagues have been studying willpower as a form of energy. They discovered that willpower burns out the longer we use it. They point out that, “Self-control requires a certain amount of glucose to operate unimpaired. A single act of self-control causes glucose to drop below optimal levels, thereby impairing subsequent attempts at self-control.”* The longer we use willpower to control ourselves, the more glucose we expend. Then, if we try to bring willpower to bear later without rest and food, we are likely to be met with faulty decision-making and the inability to focus, along with less self-control overall.

The evidence is telling us to become aware of our energy levels, especially doing difficult, control-oriented tasks. The next time you begin working on a major project, study, or get involved in an intense negotiation, make sure you “carb up” (complex carbs) and get plenty of rest before these events. Keep complex carbohydrates at hand to keep refueling your willpower. This simple tactic can be the difference between keeping on going or giving up.

 *Matthew T. Gailliot, Roy F. Baumeister, C. Nathan DeWall, Jon K. Maner, E. Ashby Plant, Dianne M. Tice, Lauren E. Brewer, and Brandon J. Schmeichel. “Self-control relies on glucose as a limited energy source: willpower is more than a metaphor.” Journal of Personality and Social Psychology 92, no. 2 (2007): 325.