Book Summary: Willpower by Baumeister, Tierney



I recently read this book. I've tried to summarize the main points below -- you can read my notes here (MSWord doc). You might also find Derek Sivers' notes useful, which can be found here.

NOTE: The general model of willpower (as a finite resource consumed with use) used in this book does not seem to represent a scientific consensus -- see the comments for more detail.

General Claims

  • Glucose acts as willpower fuel. As willpower levels drop, so do glucose levels. Willpower can be restored by raising your blood sugar. (pp. 44-48)
  • You have a finite amount of willpower that becomes depleted as you use it, and you use the same stock of willpower for all manner of tasks. (p. 35)
  • Willpower depletion amplifies emotions, desires, and cravings[i]. (pp. 30-31)

Willpower Depletion

  • Controlling emotional reactions depletes willpower. (p. 25)
  • Attempting to control thoughts (say, trying not to think of a white bear) depletes willpower. (pp. 26-27)
  • Chronic pain causes ongoing willpower depletion. (p. 36)
  • Being sick depletes glucose, which negatively affects willpower. Related note: Driving a car with a bad cold has been found to be even more dangerous than driving when mildly intoxicated. (pp. 59-60)
  • Making decisions (even trivial ones) costs willpower, and making decisions for other people costs less than making them for yourself. Making decisions that you enjoy costs less willpower than those which you do not. (pp. 94-95)
  • Uncompleted tasks and unmet goals tend to pop into one’s mind – this is called the Zeigarnik effect. Completing the task (or making a plan to do so, the more specific the better) will cause your unconscious to stop nagging you with reminders.[ii] (p. 81)

Restoring Willpower

  • Eating foods like white bread, potatoes, white rice, and sugary snacks produce boom-and-bust cycles because they are converted into glucose so quickly. Foods which are converted more slowly (providing fuel more steadily) include most veggies, nuts (like peanuts and cashews), many raw fruits (like apples, blueberries, and pears), cheese, fish, meat, and olive oil. (These foods are said to have a low glycemic index.) (pp. 59-60)
  • Sleep helps to restore willpower – in particular, sleep deprivation causes impaired processing of glucose (and, over time, a higher risk of diabetes). (pp. 59-60)
  • Being in a clean room appears to increase self-control, and being in a messy room appears to reduce self-control.[iii] (p. 156)


  • Focusing on a single self-improvement goal increases your chances of success, as each simultaneous goal increases the demands on your willpower. (pp. 37-38)
  • Conflicting goals cause increased worrying/rumination, decreased motivation, greater amount of physical sickness, and more depression and anxiety. (p. 67)
  • Reluctance to give up options increases when willpower is low.[iv](p. 99)
  • Focusing on past achievements seems to increase contentment with one’s current situation, while focusing on the road ahead increases motivation and ambition. (p. 120)
  • People are often not very good at predicting how they will behave in an excited emotional state while in an unexcited state – this is often referred to as the hot-cold empathy gap. (p. 148)
  • Precommitment can make it more likely that you will not succumb to temptation during times of low willpower.[v] (pp. 151-153)

I declare Crocker's Rules.

[i] I didn’t see enough evidence to conclude whether the cravings are actually stronger, or people are simply less able to resist them, or both. The book claims that both are true.

[ii] The book seems to imply this mental nagging costs willpower, but I don’t recall it being explicitly stated. GTD is also mentioned, and the lack of Next Actions which one has the materials to execute being included in plans causing people to procrastinate. (p. 79)

[iii] The relevant experiment was conducted in a laboratory, so there is no possibility of the experimental results being affected by the fact that people with more self-control may keep their house cleaner. Self-control was measured in ways like being willing/unwilling to week for a larger sum of money instead of receiving a smaller sum immediately, and choosing healthier foods over sugary snacks.

[iv] I wonder if this means that people are more likely to ignore opportunity costs.

[v] ‘Conserving willpower’ is also mentioned around here, which seemed to imply that effective precommitment helped reduce the willpower costs of overcoming constant temptation by making the decision easier.