How hunger can weaken willpower

I do a lot of work with groups in within businesses and organisations designed to help people lead healthier, more balanced and sustainable lives, and improve their energy, vitality and effectiveness as they do this. Early on during a programme, I’ll usually ask people what they’d like to get out of it, and non-uncommonly delegates express the wish to have the ability to exert for ‘discipline’ and ‘self-control’. I appreciate the sentiment, but to be honest when I hear terms such as these my heart sinks a bit. For me, life is difficult enough without having to expend effort and mental energy, say, actively resisting unhealthy foods and forcing oneself to make supposedly healthier choices.

I’m of the mind that healthy choices need to be enjoyable and easy. I’ve noticed over the years that one thing that can have a corrosive effect here is just plain hunger. When individuals seek to improve their diet, particularly if the goal is to lose weight, then hunger often comes into it. Some people believe (consciously or unconsciously) that hunger means they must be in caloric deficit and therefore they must be losing weight. But even if weight loss is not the goal, many individuals will find themselves hungry because they have shifted towards a diet rich in fruits and vegetables, which have some nutritional merit, but generally fail to satisfy the appetite properly.

Just this week I saw a classic example of this. An overweight man told me how 3-4 months ago he’d decided, with the assistance of his girlfriend, to improve his diet. Out went a lot of rubbishy processed, grain-based foods. In came lots of fruit and vegetables in its place. Breakfast was now a grapefruit. Mid-morning snack was more fruit. Lunch was often a vegetable soup, followed by more fruit in the afternoon. His evening meal was decent (meat or fish with vegetables).

Anyway, what was the result of all this ‘healthy eating’. Two main things: almost perpetual hunger and zero weight loss. I admired this man’s ability to persist with this regime in the absence of any tangible benefit, but also how long it would be before he gets fed up with the hunger and stagnant weight and just defaults back to his original crappy (by his own admission) diet.

Of course, he won’t be the first person to lapse from some healthy eating regime. Many individuals have the experience of ‘toughing it out’ on a ‘diet’ for a limited period of time before ‘caving’ and feeling unable to resist foods such as bread, pasta, pizza, confectionary and patisserie. And while hunger appears to sap at the resolve, I’ve noticed consistently how keeping hunger at bay makes not having these foods so, so much easier.

When an individual does not let their appetite get out of hand, they usually find it relatively easy to eschew sandwiches at lunch and opt for a better option such as a salad or soup. I read a interesting piece in the New Scientist magazine yesterday that got me thinking about this phenomenon in a whole new way.

The piece was written by psychologist Dr Roy Baumeister, co-author of the book Willpower. In the piece he makes the point that willpower is a bit like a muscle. Once it’s ‘exercised’, it is weaker for some time after. In other words, once someone has to be exert some willpower and self-discipline, their ability to do that again is diminished until the willpower has been rested for awhile. Could this help explain why dietary restraint over time almost always comes back to bite people in the bum?

But perhaps even more interesting is this scientific observation: if individuals are given sugar between two tests of self-control, they do better on the second one if they are given a sugary drink compared to an artificially sweetened one. Could it be that somehow sugar feeds the willpower ‘muscle’ and strengthen the resolve? It wouldn’t surprise me at all, given just how often people find keeping blood sugar levels stable and rampant hunger at bay makes healthy eating a relative breeze. I’ve also witnessed just how not being very hungry can lead to people automatically drinking less alcohol too.

There’s a killer paragraph in the New Scientist piece that I’m reproducing here in full:

This glucose research also suggests why dieting is so fiendishly difficult. In order to resist tempting foods, we need willpower but to have willpower, we must eat. The essence of dieting (restricting food intake) robs us of the psychological strength needed to succeed. Perhaps dieters should concentrate on filling up with healthy food so they have the willpower to resist fattening stuff.

Yes, yes and yes, Dr Baumeister! Psychology may be his thing, but I feel he may have missed another potential vocation as a weight loss and healthy eating expert.


1. Baumeister RF. Weak will comes from tired mental muscles. New Scientist. 1 February 2012.

10 Responses to How hunger can weaken willpower

  1. Jenny 2 February 2012 at 7:34 pm #

    This article in The Times:
    is finally coming out in favour of wheat free/primal diet.

  2. Alexandra 4 February 2012 at 5:20 pm #

    For me the solution to my life of being always hungry (and fat!) is to eat a very low carb diet with plenty of good fat, including saturated fat. I eat until I am full, I never worry about calories or restrict my portions. This has been life changing! For me, carbohydrates clearly drive appetite and I now am indifferent to food between meals and rarely, if ever, desire snacks. I am well over 120 pounds lighter and feel healthy and energetic eating very low carb paleo.

  3. PeggyC 4 February 2012 at 10:33 pm #

    I so agree. I’ve tried all the popular diets–low fat, Zone, volumetrics, some version of Weight Watchers, vegetarian, you name it. I’ve tried it. Every time I eventually had to give up–hunger got to me. Now I am living a low carb lifestyle (no, not diet, lifestyle!) I am never hungry, except when it is time to eat, so I know I will be able to sustain it for the rest of my life. And yes, my weight/shape has returned to a pretty healthy one for my age. No more fear of fat, no more hunger. It’s awesome.

  4. Dan 5 February 2012 at 2:35 am #

    I have to reiterate what Alexandra and Peggy have already said. Having gone on numerous diets before they eventually failed because of constantly feeling hungry. The worst was at night, after my last meal, and just sitting their using all my willpower to keep myself from eating. On low carb I just don’t feel hungry anymore and, although I have cravings for ice cream, these are by no means the same ‘hunger’ as I felt on the other diets. These are just ‘oh it would be nice to have ice cream’ but so easy to say no.

  5. Michelle 5 February 2012 at 2:59 am #

    I have to agree 100%. Starvation is not the answer to losing weight, at least not in the long run. A consistent healthy eating plan is the best way to reach and maintain a healthy weight. Eating sensible amounts of real food and yes occasionally indulging will keep hunger at bay. Unfortunately most people want quick results and resort to fad diets or starving themselves to lose weight fast. As mentioned in the post, people who are hungry will eventually need to satisfy this most basic urge, and usually the results aren’t pretty.

  6. jake3_14 6 February 2012 at 10:44 pm #

    There’s a saying on the forum: “Being fat is hard. Being healthy is hard. Pick your hard.” While a low-carb lifestyle keeps hunger in check, it requires as much discipline as anything else I’ve ever done. You have to put up with social disapproval, eating out is hazardous, and you have to allocate more money, time, and mental effort to food. Moreover, there is some evidence that after a prolonged period of being overweight, you alter key hormonal responses (e.g., hyperinsulemia in response to eating carbs), so that you forever have a deranged metabolism that fights to be fat again.

    So, Dr. Briffa, please be realistic with your clients and patients. You’ll do them a service if you advise them on how to handle the many headwinds against getting and staying healthy in today’s society.

  7. Dr John Briffa 10 February 2012 at 3:51 pm #


    While a low-carb lifestyle keeps hunger in check, it requires as much discipline as anything else I’ve ever done. You have to put up with social disapproval, eating out is hazardous, and you have to allocate more money, time, and mental effort to food.

    These things might be the case for you, but my overwhelming experience is that these things are not true for many others. Actually, quite the reverse.

  8. Alexandra 13 February 2012 at 12:57 am #

    After four years, I don’t find it hard at all. It just feels right, the way I was meant to eat all along.
    I would say to people eating low carb but still fighting powerful cravings…. go lower on the carbs, get the grains out don’t need them, go easy on fruit, make sure you are eating enough fat and meat/fish. Find the carb level where food matters less and doesn’t occupy your thoughts except when you are truly hungry two or three times each day. It does not need to be a struggle, just keep tinkering.

  9. Martin Levac 13 February 2012 at 2:26 pm #

    Dr Briffa, there’s a major flaw in the study. Obviously, the assumption is that glucose is the preferred fuel for the brain. They compare sugar to artificial sweetener. They conclude that providing this preferred fuel to the brain improves willpower. Artificial sweetener is not fuel for anything, let alone the brain. The conclusion should be that providing _any_ fuel to the brain improves willpower. Ketones is also an adequate fuel for the brain. If they’d compared sugar to fat, they’d have found a different result. Maybe they’d have found that fat (which converts to ketones in the liver) is in fact the preferred fuel for the brain, and improves willpower more than sugar. Granted, they’d have had to make sure that those who ate the fat were keto-adapted, just like those who ate the sugar were most probably gluco-adapted.

  10. Mack Parnell 21 February 2012 at 6:53 pm #

    Hunger can also stop you exercising to the correct intensity. if you are going to the gym on an empty stomach there is not much chance you will be training as hard you would if keeping up with regular meals. This can be detrimental to achieving your fitness and weight loss/control goals as you need to be progressively training harder or heavier each time you go, if you are feeling too hungry your energy levels will be zapped and you will never feel like progressing and often cut your workout short.

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