Is willpower a muscle?

Picture of Dr. Jen Kerns

Dr. Jen Kerns

When trying to watch what you eat, have you ever noticed that it’s easier to stick to your guns early in the day, but by late afternoon or evening you find it 10 times harder to resist those chips or that brownie? One of the most important factors in someone’s ability to lose weight is self-control, or willpower. An obese person’s ability to resist the impulse to eat calorie-dense foods, especially with junk food available around every corner, is critical to his or her weight loss success.

Researchers have found that willpower may be more like a muscle than we realized. And just like a muscle that fatigues after being used repetitively, willpower can fatigue with use, too. Muraven, Tice and Baumeister did a series of experiments in 1998 that found that people reported feeling fatigued after making an effort to control themselves, and the more difficult the challenge to their willpower, the more fatigue they reported. Then these people actually did worse when they were confronted with a subsequent unrelated test of self-control. Muraven, Tice and Baumeister speculated that, like physical exertion, someone’s capacity for self-control might draw on a limited resource and become depleted with short-term use, just like a muscle becomes fatigues after short-term use — but they also suspected that willpower might actually increase over time with repeated use much as someone’s physical fitness increases over time with repeated bouts of exercise.

In fact, Mark Muraven did an experiment in 2010 that confirmed this theory: people who practiced unrelated tasks that actually required them to exert their willpower did better in the real-life challenge of quitting smoking.

This can have important implication for those of us trying to change our eating habits. Practicing small instances of willpower on a regular basis might actually improve our ability to control ourselves around junk food later on. And trying to face challenges to our self-control when we are already fatigued might be a recipe for disaster. Could this be why recent research has found a correlation between sleep deprivation and weight gain/obesity? Something to think about….


Muraven, M. (2010). Practicing self-control lowers the risk of smoking lapse. Psychology of Addictive Behaviors, 24(3), 446-452. doi:10.1037/a0018545

Muraven, M., Tice, D. M., & Baumeister, R. F. (1998). Self-control as limited resource: Regulatory depletion patterns. Journal of Personality and Social Psychology, 74(3), 774-788.




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