How Willpower Works: The Science of Decision Fatigue and How to Avoid Bad Decisions

Why do we make unhealthy and unproductive choices — even when we know we should do better?

If you ask most people, they will say that poor choices are a result of a “lack of willpower.”

But research from Columbia University is beginning to reveal that willpower doesn’t quite work that way.

In fact, you may be surprised just how much small daily decisions impact the willpower you have for important choices. And most importantly, it turns out there are simple choices you can make that will help you master your willpower and make better decisions on a more consistent basis.

Here’s the deal…

Why Some Criminals Don’t Get a Fair Hearing

In a research study published by the National Academy of Sciences, psychologists examined the factors that impact whether or not a judge approves a criminal for parole.

The researchers examined 1,112 judicial rulings over a 10-month period. All of the rulings were made by a parole board judge, who was determining whether or not to allow the criminal to be released from prison on parole. (In some cases, the criminal was asking not for a release, but rather for a change in parole terms.)

Now, you might assume that the judges were influenced by factors like the type of crime committed or the particular laws that were broken.

But the researchers found exactly the opposite. The choices made by judges are impacted by all types of things that shouldn’t have an effect in the courtroom. Most notably, the time of day.

What the researchers found was that at the beginning of the day, a judge was likely to give a favorable ruling about 65 percent of the time. However, as the morning wore on and the judge became drained from making more and more decisions, the likelihood of a criminal getting a favorable ruling steadily dropped to zero.

After taking a lunch break, however, the judge would return to the courtroom refreshed and the likelihood of a favorable ruling would immediately jump back up to 65 percent. And then, as the hours moved on, the percentage of favorable rulings would fall back down to zero by the end of the day.

This trend held true for more than 1,100 cases. It didn’t matter what the crime was — murder, rape, theft, embezzlement — a criminal was much more likely to get a favorable response if their parole hearing was scheduled in the morning (or immediately after a food break) than if it was scheduled near the end of a long session.

The figure below depicts the odds that a judge will make a favorable ruling based on the time of the day. The dotted lines signify food breaks taken throughout the day.

This graph displays the odds that a criminal will receive a favorable response from the judge based on the time of day when the hearing occurs. Notice that as time goes on, the odds of receiving a favorable response decrease. (Graphic by James Clear.)
This graph displays the odds that a criminal will receive a favorable response from the judge based on the time of day when the hearing occurs. Notice that as time goes on, the odds of receiving a favorable response decrease. (Graphic by James Clear.)

What’s Going on Here?

As it turns out, your willpower is like a muscle. And similar to the muscles in your body, willpower can get fatigued when you use it over and over again. Every time you make a decision, it’s like doing another rep in the gym. And similar to how your muscles get tired at the end of a workout, the strength of your willpower fades as you make more decisions.

Researchers often refer to this phenomenon as decision fatigue. When the judge on a parole board experiences decision fatigue, they deny more parole requests.

This makes sense. When your willpower is fading and your brain is tired of making decisions, it’s easier just to say no and keep everyone locked up than it is to debate whether or not someone is trustworthy enough to leave prison. At the beginning of the day, a judge will give each case a fair shot. But as their energy starts to fade? Deny, deny, deny.

Here’s why this is important for you…

Do You Suffer From Decision Fatigue?

Decision fatigue happens every day in your life as well. If you have a particularly decision-heavy day at work, then you come home feeling drained. You might want to go to the gym and workout, but your brain would rather default to the easy decision: sit on the couch. That’s decision fatigue.

The same thing is true if you find it hard to muster up the willpower to work on your side business at night or to cook a healthy meal for dinner.

And while decision fatigue is something that we all deal with, there are a few ways that you can organize your life and design your day to master your willpower.

5 Ways to Overcome Decision Fatigue

1. Plan daily decisions the night before.

There will always be decisions that pop up each day that you can’t plan for. That’s fine. It’s just part of life.

But for most of us, the decisions that drain us are the ones that we make over and over and over again. Wasting precious willpower these decisions — which could be automated or planned in advance — is one reason why many people feel so drained at the end of the day.

For example, decisions like…

What am I going to wear to work? What should I eat for breakfast? Should I go to the dry cleaner before or after work? And so on.

All of those examples above, can be decided in 3 minutes or less the night before, which means you won’t be wasting your willpower on those choices the next day. Taking time to plan out, simplify, and design the repeated daily decisions will give you more mental space to make the important choices each day.

2. Do the most important thing first.

If there was the most important court case in the world, when would you want the judge to hear it?

Based on the research above, first thing in the morning. You’d want their best attention, energy, and focus to go toward the decisions that were most important.

The same thing goes for your work and life. What’s the most important thing for you right now?

Is it getting in shape? Is it building your business? Is it writing that book you have inside of you? Is it learning to eliminate stress and relax?

Whatever it is for you, put your best energy toward it. If you have to wake up 30 minutes earlier, then do that. Start your day by working on the most important thing in your life.

I’ve written previously about the importance of morning routines and time management, this research on willpower is just another reason to work on the most important things first.

3. Stop making decisions. Start making commitments.

I think advice like, “you just need to decide to do it” gets dished around too much.

Yes, of course you need to decide to do the things that are important to you, but more than that you need to schedule them into your life.

We all have things that we say are important to us.

“I really want to scale my business.”

“I really want to lose 40 pounds.”

“I really want to get started on XYZ.”

Unfortunately, most of us simply hope that we’ll have the willpower and motivation to make the right decisions each day.

Rather than hoping that I’ll make the right choice each day, I’ve found much more success by scheduling the things that are important to me.

For example, my schedule for writing is Monday and Thursday. My schedule for weightlifting is Monday, Wednesday, Friday. On any given Monday, I don’t have to decide whether I’m going to write. It’s already on the schedule. And I’m not hoping that I’ll have enough willpower to make it to the gym. It’s just where I go on Mondays at 6pm.

If you sit back and hope that you’ll be able to make the right decisions each day, then you will certainly fall victim to decision fatigue and a lack of willpower.

4. If you have to make good decisions later in the day, then eat something first.

It’s no coincidence that the judges became better decision makers after eating. Now, if you cram french fries into your veins every day, then I doubt that you’ll enjoy the same results. But taking a break to feed your brain is a wonderful way to boost willpower.

This is especially important because although it’s great to do the most important thing first, it’s not always possible to organize your day like that.

When you want to get better decisions from your mind, put better food into your body.

5. Simplify.

Whether you are trying to reach the highest level of performance or just want to start eating a healthy diet, the biggest frustration for most people is the feeling that you need to use willpower on an hourly basis.

Find ways to simplify your life. If something isn’t important to you, eliminate it. Making decisions about unimportant things, even if you have the time to do so, isn’t a benign task. It’s pulling precious energy and willpower from the things that matter.

Willpower is one area of life where you can most certainly improve your output by reducing the number of inputs.

The Bottom Line

Willpower isn’t something you have or something you lack. It rises and falls. And while it’s impossible to maximize your willpower for every moment of every day, it is possible to make a few changes to your day and your routine so that you can get the most of your decisions and make consistent progress on the things that are important to you.

Hat tip to John Tierney and his article for the New York Times, where I originally learned about decision fatigue.


  1. All great and sound advice you gave here, James. The statistics on the judge’s rulings are frightening though. I’ve heard something about that a while ago but not in such detail.

    It’s crazy to think that trivial details (like time of day) can have such a large impact on our actions which also affect others.

    I’ve heard that creativity often “flows” better when you’re more tired. Maybe it’s a coincidence, but I find that to be true for me too. My best creative ideas come out when I’m sort of drained. Do you think there’s a connection between this claim and decision fatigue? Not exactly the same, but I couldn’t help but ask.

    • Vincent, I agree with your assessment of creative ideas! I think it’s because creative decision making requires fatigue. It’s not about being awake, alert, and in a good mood, easily ready to say yes because you are feeling great. In creative decision making we are often being true to our own creative vision. All day long we are alert, and learn about which creative professional is making the most money and how they’re doing it. Logically we think we need to be more like the high grossing pros. After we spend all day trying to execute a vision that’s not authentically ours we get nothing done. In reality we are more uninhibited at the end of the day, late at night when we are working and HAVE to get it done because then we don’t have time to mull over how someone else would do it. At that point we have to draw on our own strengths and execute our own vision to get the job done.

      • Hi Vincent and Christa,

        I agree with the creativity bit. And I think it’s mostly because fatigue keeps the biggest enemy of creativity at bay.

        Analysis. Our brain doesn’t want to analyze anything when it’s fatigued and therefore allows uninhibited, uncensored flow of creativity.

  2. Very interesting article James, and love how (like all your articles) it is grounded with good scientific backing. I have now started printing them off so I can read through and apply the awesome tips you give throughout the week. Thanks heaps man.

  3. Love all your posts! I really enjoy all the helpful tools you give that we can apply to our daily lives to better ourselves. Thank you!

  4. James,

    Thanks for sharing this valuable content with the world! I’ve recently subscribed to your blog and I really enjoy reading your posts. I too believe that commitment is a valuable principle to adhere to. Relying on motivation and will power alone will fail us when those periods of fatigue creep in, but if we’ve already committed to do the things we need to do then we are locked in. Commitment is a powerful habit to have for sure!

  5. This was beyond fascinating to me. I began working in the court system when I was 17 and I’m almost 40. Since leaving the legal field (3/13), I’ve been inundated with statistics, many of which are disturbing such as these. When you’re on the inside you simply don’t see the inconsistencies. I have to wonder how detailed these statistics were and to what depths of the cases were examined. Sure, possibly the same or similar crime or offense. What about consideration of the DCH aka Defendeant Case History? Every person has a different criminal background and priors weigh heavily on a Judge’s conscience when determining release on P/R. Along with other factors, i.e. connectivity to the community, flight risk, local family support. I am not intending to doubt your support or blog. Let me clarify – you are ONE of a couple of writers who I read – everything you write. To that end, consider my comments a compliment. I interact because I admire and respect you. On a personal note, I am BEYOND fatigued. Life has handed me so much and add a horrible cold to it and I’m literally on my back. Willpower in tact though…. so I’ll bounce back and push onward. I look forward to hearing about your travels, seminars, conferences, whatever you’re scheming. Haha. Your positivity and transparency shine and I aspire to have a following like yours some day. Many blessings to you. You deserve it. Oh, and maybe you played some good ball (I’ve been known to have a connection with baseball players), I can honestly say that your writing is more inspiring to me than if you had a Yankees annual salary. Fulfill your calling. You’ll be far more “wealthy” by sharing with us. I truly believe that.

  6. I buy that willpower per day can be a finite proposition, and that scheduling those kinds of things works around having to make a decision and be strong about it everyday. However, I detect a “morning person” slant or bias to the article. My brain is too fuzzy earlier in the morning to make important decisions. But, I can agree to making better decisions after eating. My most productive work time is the hours after my lunch break. :)

  7. Hi James, I am new to your blog and am loving it.

    In this particular case, is “willpower” the right issue? It seems like the ability to make objective decision making is affected by brain fatigue but not really will power.

    For example, if the decision is related to exercising, then you not only exercise you will power each day but you need to exercise it consistently across many days/month. However,for someone making a budget decision, whether morning, noon or night, it is an issue of having the intellectual and emotional clarity to make the right decision and not really will power.

    In the study of decision made on paroles, the judges did not have a will to judge each case one way or the other. Their will was to make the right decision on each case and they failed, the cause being brain/mind fatigue.

    Hope this makes sense.

    If it does, we could take it one step further with the question, does fatigue affect only our ability to judge with clarity because of low intellectual and emotional resources or does fatigue even reduce our moral resources?

  8. Thanks James for your wonderful article.
    It reminds me of my school days wherein we prepare ourself day before for our school that is right from ironing our uniform , filling our bags according to timetable and doing our day work as per schedule.
    Further your artcile threw the light on the reasons we are not able to take proper decisions and yes even i felt the fatigues and which also lead to improper decision.
    And YES COMMITMENT is very Important.

  9. Good read.

    I find myself occasionally reading these posts aloud for an audience of 2 :).

    I would suggest that you can’t be sure that the decision-making rejuvenation is coming from a meal… maybe it is just the break itself.

    A *very* good book on this topic is “The Power of Full Engagement”.

    Their assertion, after working with top athletes and business executives is:

    “managing energy, not time, is the key to high performance and personal renewal”

  10. This is very illuminating and very useful.

    The idea that will power functions like a fatiging muscle is a very clever analogy and the advice about making decisions ahead of time so as not to fatigue your limited will power is useful and clever.

    Will definitley be trying that advice. Thanks J.

  11. Great article James!

    It is crazy how real decision making fatigue is, especially to me as a college student.

    I have been trying to dial in solid eating habits for quite some time now. I would LOVE to eat a diverse diet. The problem is that I waste a considerable amount of time during my day trying to plan a delicious, but new meal. I know this takes away from other important decisions I need to make during the school day.

    For the past two weeks I have pretty much ate the same 3 meals every day and I feel it helps save brain power. However, I want a diverse group of foods!

    I was curious if you have any thoughts on this and how you plan your meals. I’m also an athlete.

  12. Awesome information. This is why I spend 5 hours every weekend cooking for the week. I have some pretty focused dietary goals and find if I don’t have something ready to eat, right in front of me I always make the bad choice.

  13. James,

    Really enjoy your work, as I hope you know from past comments. I think consideration needs to be given to blood glucose level variability, and it’s effect upon brain function. A drop in blood glucose hours after eating a high carbohydrate, (high glycemic index) which would happen at about the same times noted in the study, can effect the decision making process and even the “will” to make decisions. It may be that a solution can be found in the suggestions you make, but they seen to be more about treating the symptoms, rather than addressing the cause, which may be poor nutritional habits. Your solution is the more practical, considering the nutritional habits of most people, but lowering blood glucose levels throughout the day and eating more protein and fat can give the energy to make decisions all day long. I have recently, (past two years) experimented with nutritional plans, not diets, and have found that a low blood glucose level throughout the day, with fat and protein, noting that each person must find their levels, significantly enhances body and brain energy levels.

  14. It’s funny! Was reading about same thing in “Thinking, Fast and Slow”, by Daniel Kahneman (a Nobel laureate and path-breaking psychologist and researcher).

    Decision fatigue, also referred to as Ego Depletion can be averted with glucose being taken to restore one’s ‘self-control’ (I guess that’s willpower). The ‘Thinking Slow’ is all about effortful processing that involves holding ideas in one’s working memory as one applies reasoning and logic — that’s decision making … and this requires one to ‘pay attention’ which comes from a limited budget of mental energy which is shared by self-control and cognitive effort. So, if one there’s an energy budget depletion both self-control and cognitive function suffer!

    A fascinating read, this subject.

  15. James, I heard this research presented with an additional factor: blood sugar. Eating elevates blood sugar and that ‘improves’ the decision-making energy of the judges. One suggestion was to have a snack mid-morning and mid-afternoon to reverse or lessen the effects of decision-fatigue. Any thoughts on this?

  16. Really enjoyed reading this. Decision fatigue is something I currently struggle with. I have never really put it down to willpower or the lack thereof though. It has always been too much focus on the results (or lack thereof). :-)

    Enlightening post!

  17. James, great article as always, I just wanted to add one more consideration about the study. One of the factors besides the time of day can be the monotony of his work, wonder how his “daily rejection curve” would look if he, for example split his job in two shifts and spend a few hours in between doing something completely unrelated (like relaxing with his family). But since we both know such studies (even if more judges were included) are demonstrating correlation at best (and not necessarily causation) it really makes sense for everyone to try things out for themselves.

    During my own research into this subject and what has in the end best worked for me, I have actually come to believe that trying to “exercise” your willpower towards changing your habits is not only the hardest way, but it can actually be counterproductive (since it predisposes a state of inner conflict we must learn to be able to “fight” for the foreseeable future). In my opinion the solution is better sought after in the direction of lessening the severity of our decisions (or more precise our perception of them). Just my 5c. :)

    Keep up the good work…

  18. Hi James, I’m 55 yrs of age and diagnosed with ADHD last year. I do take medication daily and found it has made a surprising difference, particularly when I was studying last year. This disability has been with me all my life and therefore I have been destructive in career choices and in love life. With the help of a psychologist and medication, I’ve had to rethink, organise, prioritise, my life and now feel like I have more control. Naturally the psychologist and medication can only do so much and the rest is up to me. So lately I’ve read a few prints but found little impact in retraining myself. I’m not sure how I came across your site, but have found inspiration in your articles. It is a challenging, anxious but exciting path ahead and your writing certainly does have an impact in readjusting my way of life. Great articles on motivation, routine, creativity and now decision fatigue. I look forward to your posts and will keep tweaking my thoughts, habits and decisions.

Leave a comment Share your knowledge and experience.