The Real Reason Dieting Is So Hard, and Why It Matters for CEOs

What does dieting have to do with running a business?  Apparently, quite a bit.

According to a fascinating NY Times Magazine article entitled ‘Do You Suffer From Decision Fatigue?, researchers have recently discovered a paradox that helps to explain why dieting is so challenging:


  1. In order not to eat, a dieter needs willpower.
  2. In order to have willpower, a dieter needs to eat.


As we all know (and most of us have experienced at some point), dieting involves making a series of decisions to resist the temptation of eating food that you’ve committed not to eat.  Over the last several years researchers have discovered that (1) we have a finite store of mental energy for exercising self-control and making rational choices, (2) each decision we make depletes that store of mental energy (causing ‘ego depletion’), and  (3) the amount of glucose in our body directly impacts that store of mental energy.

Study 1: We actually have a limited amount of willpower
In one study mentioned in the article (also highlighted in the insightful book Switch by Chip and Dan Heath), researchers randomly assigned subjects into two groups – A and B, and told them they were undergoing a study of ‘taste perceptions’. Both groups sat around a table which had on it one bowl of freshly-baked chocolate chip cookies and one bowl of radishes. Group A was told to please eat the radishes and to please not touch the cookies, as they were for a different experiment (which, as you can imagine, requires a great deal of willpower).  Group B was told the opposite, to please eat the cookies and not touch the radishes (not so much willpower required for that one). Each group was then asked to complete a set of extremely challenging geometry puzzles.  Here’s what they found: Subjects in Group A spent nearly 60% less time trying to solve the puzzles than subjects in Group B (8 minutes v. 19 minutes). Subjects in Group A had depleted their finite store of mental energy for exerting self-control, and simply didn’t have as much left over to devote to the geometry puzzle as those in Group B did.

Study 2: Each decision we make depletes our willpower and ability to make decisions
A more recent study showed that the same effect occurs when people have to make a number of decisions, rather than resist temptation.
According to the article’s description of the study: “a nearby department store was holding a going-out-of-business sale, so researchers from the lab went off to fill their car trunks with simple products … of sufficient quality to … appeal to college students. When they came to the lab, the students were told they would get to keep one item at the end of the experiment, but first they had to make a series of choices. Would they prefer a pen or a candle? A vanilla-scented candle or an almond-scented one? A candle or a T-shirt? A black T-shirt or a red T-shirt? A control group, meanwhile — let’s call them the nondeciders — spent an equally long period contemplating all these same products without having to make any choices. They were asked just to give their opinion of each product and report how often they had used such a product in the last six months.

Afterward, all the participants were given one of the classic tests of self-control: holding your hand in ice water for as long as you can. The impulse is to pull your hand out, so self-discipline is needed to keep the hand underwater. The deciders gave up much faster; they lasted 28 seconds, less than half the 67-second average of the nondeciders. Making all those choices had apparently sapped their willpower.”

Study 3: Glucose (sugar) directly impacts our willpower and decision-making ability
In a third study, researchers ran a similar set of tests to the one described in the first study with the chocolate chip cookies, in which students are asked to perform tasks requiring willpower.  In this study, the two groups were given the same tasks requiring the same amount of willpower, but one group was given lemonade mixed with sugar and the other group was given lemonade mixed with a diet sweetener. While both lemonades tasted the same, the sugar provided a burst of glucose while the sweetener did not.  Study after study showed that the sugar restored the willpower, while the artificial sweetener had no effect. “The glucose would at least mitigate the ego depletion and sometimes completely reversed it.”

Conservation of Energy
In Dr. Dan Siegel’s fascinating book Mindsight, he describes the mind as an “embodied and relational process that regulates the flow of energy and information.”  Essentially, these studies are showing that we only have so much mental energy and that impacts our ability to process information. Our limited mental energy begins to be drained from the moment we wake up as we (1) resisting temptation (which we do all day long when we work instead of play, eat a balanced diet, and avoid falling asleep at our desks), (2) make decisions and (3) use up the glucose in our bodies.

When our mental energy is drained, our brains start to conserve the energy normally used to think through consequences, leading us to (1) act impulsively, or (2) do nothing.  With our capacity to think through consequences diminished, we’re more likely to blow up at colleagues and family members, buy junk food and pick fights. And we are more likely to choose the status quo and avoid making choices that require significant thought or that imply significant change.

So What?
In a study of character strengths surveying more than 1 million people around the world, self-control came in dead last. Yet, self-control is one of the most important factors in your team’s ability to work well together, focus and get things done, and make good decisions. Your goal is not for your people to just physically to show up everyday, but to be able to harness their minds to the fullest extent possible toward achieving the company’s objectives.

So, here are some practical, tactical implications for CEOs, executives and managers to maximize how you use your and your team’s limited store of mental energy:

For Yourself:

  1. Conserve your willpower by developing habits and routines that reduce the number of decision you have to make each day. This could include everything from a fixed rotation of outfits to eating the same meal for breakfast to planning and structuring your day in advance. Notice how brushing your teeth requires approximately zero willpower; once you create new habits and routines, you’ll free up mental energy for other decisions and goals.
  2. Eat breakfast. Yet another piece of evidence that breakfast is the most important meal of the day. Filling your brain with glucose (ideally slow-releasing glycogen in whole grains) at the beginning of the day will help to maximize your brain functioning.
  3. Eat small meals throughout the day. To continually fill your stores of mental energy, try eating small meals and healthy snacks every few hours. Avoid making important decisions on an empty stomach when you’re less likely to have the energy to fully think through them.
  4. Make your most important decisions first thing in the morning. If you know you have important decisions to make, it’s best to make them first thing in the morning (ideally after a nutritious breakfast) before your mental energy has been depleted by other decisions and temptations resisted throughout the day. Avoid making big decisions at the end of the day.  In their insightful HBR article entitled ‘Manage Your Energy, Not Your Time’, Tony Schwartz and Catherine McCarthy recommend the following: “Every night, identify the most important challenge for the next day. Then make it your first priority when you arrive at work in the morning.”
  5. Don’t make too many important decisions in a row. Since each decision depletes your ability to think clearly, try not to make too many decisions in sequence or even in one day.

For Your Teams:

  1. Create clear rules, routines and processes that reduce the number of trivial decisions your team members need to make each day. While it’s important to give your team the autonomy to make key business decisions within their scope of responsibility, reducing the number of other, more trivial decisions they make throughout the day.
  2. Serve breakfast. May employees roll out of bed and rush into work, without having a chance to eat breakfast. Serving breakfast at work can help fill your team’s stores of mental energy.
  3. Keep your team well-fed throughout the day (ideally with healthy, slow-release glycogen-rich foods like whole grains). This is critical to optimal performance and decision-making, not just an employee perk. Have healthy snacks and consider providing nutritious meals.
  4. Create organizational processes and routines that lead to big decisions being made early in the day by people who have full stomachs. When planning on-going meetings that require your team’s best thoughts and decision-making, try to schedule them toward the beginning of the day, and provide food if people haven’t eaten.
  5. Minimize tempting distractions. To the extent possible, encourage your team members to keep only one window open on their computer and to shut down email, news sites and other non-relevant webpages while they’re working on a particular task. By eliminating the constant temptation to check that new email or news story, team members will be able to conserve the energy they would otherwise spend resisting these temptations.

Like dieters struggling to resist the temptation to eat without the fuel that would energize them to do the resisting, workers are increasingly being asked to work longer hours while having to make more and more complex decisions. Leaders will be well served to remember that (1) we have a finite store of mental energy for exercising self-control and making rational choices, (2) each decision we make depletes that store of mental energy, and  (3) the amount of glucose in our body directly impacts that store of mental energy. With this in mind, what will you do to start making better use of your and your team’s limited mental energy?

3 Comments on “The Real Reason Dieting Is So Hard, and Why It Matters for CEOs”

  1. Pamela D says:

    Thank you – great article. Good to put all of the unimportant things (breakfast choices) on ‘auto-decide’ and save my juice for the important issues.

  2. Fantastic article, Dave!

  3. schwanson says:

    A common corporate solution to the problem of low glucose and mental/decision fatigue is…

    …kitchen shelves and refrigerators stocked with snacks, drinks and goodies that package and repackage sugar in every way shape and form. This is a considered a ‘perk’ in return for the extra hours you spend at work.

    They don’t realize that stuffing their employees with crap is only going to lead to their poor health and dwindling productivity in the long-run.

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