Forbidding foods may cause us to obsess about them, and what to do about it

I came across this story today in the Daily Mail, concerning what can happen when we deny ourselves something. Apparently, according to this research, resisting something we desire can make us think about it more. Interestingly, if the same thing is denied to people more generally, it tends not to have this effect [1]. So, someone who is perhaps trying not to drink alcohol may find themselves thinking about alcohol more than is healthy. However, if that person were to live in a country in which alcohol was prohibited, then not drinking alcohol might present less of a challenge.

One might argue then that forbidding certain foods or drinks in the name of healthy eating may encourage a somewhat unhealthy relationship with food. I think I’ve seen a few examples of this in my time, and it’s one reason why I generally give the advice that ‘it’s what we eat most of the time, not some of it, that’s most important’. So, even if someone were eating a decent ‘primal’ diet based on natural unprocessed foods, I’m generally relaxed about the occasional consumption of bread, pasta or pizza, for instance (assuming someone does not have a contraindication such as coeliac disease).

However, I also know that the ideal is really for people to get a to a place where they are ambivalent about whether they have a food or not. Because if someone is not fussed about whether they eat something, and has not particular drive to eat it either, then actually there’s no need to even think about forbidding the food – it’s largely a non-event.

One thing that tends to work well here is to avoid getting very hungry, because when we do, there’s often a tendency to crave or desire foods such as cake, biscuits/cookies, and doughnuts. Should we get such a craving, we are usually going to have to exert some considerable willpower to resist it. And willpower has been shown to be a bit like a muscle: once exercised, it is weaker for some time later. So, repeatedly using willpower to resist a food will usually make resisting it harder and harder over time.

Research has found that if individuals are given a sugary drink between two tests of self-control, they do better on the second one [2]. The same effect does not occur if the drink is artificially sweetened, suggesting that somehow sugar feeds the willpower ‘muscle’ and strengthens the resolve. Eating a diet that helps stabilise blood sugar levels regularly enough to keep hunger and low blood sugar at bay can, I think, go a long way to essentially putting a stop to cravings for sugary and none-too-healthy foods. It also likely strengthens the resolve.

But what is also interesting, I think, is that the very act of exerting willpower tends to cause blood sugar levels to drop [3]. So, a spot of hunger and low blood sugar may trigger the need for willpower and sap it at the same time. No wonder so many of us can find it almost impossible to resist sweet foodstuffs from time to time.

Again, the key to making life a lot easier is not really wanting the food in the first place, and blood sugar stability is critical here. But it can often help to supplement with key nutrients. Two supplements I use quite a lot in practice are:

1. L-glutamine. A pinch of the amino acid L-glutamine power allowed to dissolve under the tongue can, I find, reduce an intense craving for something sweet within a few minutes.

2. L-tryptophan. This amino acid is a precursor of the brain chemical serotonin, low levels of which can provoke cravings for sweet foods and perhaps other carbohydrates. Serotonin levels naturally fall during the day, which means some individuals find their problem time is in the evening here. 500-1,500 mg taken on an empty stomach in the mid-afternoon and early evening will often really help to reduce an unhealthy drive for carbohydrate.


1. Truong G, et al. An unforgettable apple: Memory and attention for forbidden objects. Cogn Affect Behav Neurosci. 2013 May 24. [Epub ahead of print]

2. Gailliot MT, et al. Self-control relies on glucose as a limited energy source: willpower is more than a metaphor. J Pers Soc Psychol. 2007;92(2):325-36

3. Gailliot MT, et al. The physiology of willpower: linking blood glucose to self-control. Pers Soc Psychol Rev. 2007;11(4):303-27

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16 Responses to Forbidding foods may cause us to obsess about them, and what to do about it

  1. William L. Wilson, M.D. 7 June 2013 at 5:06 pm #

    I agree that an occasional dietary lapse is generally no big deal for someone who is healthy. We now believe that although carbohydrate cravings are hard-wired into our brains, they only emerged under emergency situations throughout our evolutionary history—when we were running out of food and our glucose levels dropped too low. Eating a carbohydrate is the quickest way to restore normal glucose levels.

    When Mother Nature made our brain, she didn’t anticipate that we would be eating Twinkies. When you consume this type of food you end up with a magnified glucose spike followed by a crash below normal. Your brain didn’t evolve to read glucose spikes but it does know what it means when your glucose drops too low—it’s time to eat! Thus consuming sugar and high glycemic carbohydrates trigger these cravings inappropriately.

    We now believe that in modern humans cravings for sweet and starchy foods are always pathological and a sign of a form of food-induced brain dysfunction called Carbohydrate Associated Reversible Brain syndrome or CARB syndrome. In addition to carbohydrate cravings, patients with CARB syndrome can develop up to 22 brain dysfunction symptoms over time. These cravings are a warning sign that your brain is taking you down a dangerous pathway. People with normal brain function never seem to have such cravings.

    I use a combination of L-glutamine, L-tyrosine and 5-htp to suppress these cravings in my patients.

  2. RadiantLux 7 June 2013 at 5:20 pm #

    Some of this is psychological and some is physiological. I started taking L-Glutamine in between meals after reading the Diet Cure by Julia Ross. It helped me very much.

    If I have been following the low carb lifestyle strictly, I am better able to avoid temptation because I don’t want to ruin the benefits I have received from the previous days or weeks. If I have been lax it is easier to eat a starch in front of me. That could be psychological but it could also be blood sugar stability.

  3. Adele 7 June 2013 at 6:07 pm #

    As a diebetic your views make good sense.
    Would like to know your views on the Paleo diet and whether it would
    reduce glucose cravings and even “cure” diabetese as claimed.

  4. Mark 7 June 2013 at 6:48 pm #

    I’m not so sure about the bit in the article where it states:

    ” if the same thing is denied to people more generally, it tends not to have this effect [1]. So, someone who is perhaps trying not to drink alcohol may find themselves thinking about alcohol more than is healthy. However, if that person were to live in a country in which alcohol was prohibited, then not drinking alcohol might present less of a challenge.”

    I am more or less tee total – just don’t like the taste of alcohol. I probably drink about once a year when under extreme peer pressure to do so!
    However, I have spent some time in Saudi Arabia, a totally “dry” country (but where perversely, alcohol is plentiful and parties frequent). Even though I’m normally tee total, when it was forbidden, I really found myself wanting to have a drink! One for the psychologists!

  5. Glyn Blackett 7 June 2013 at 8:16 pm #

    The book “Maximum Willpower” by Kelly McGonigal is well worth a read, if you’re interested in research on willpower. One of the best books I’ve read in years.

  6. Robert Park 7 June 2013 at 9:53 pm #

    How coincidental as I have just launched into a no grains diet. Now at the end of my second day I find that my body feels lighter and the severe gout symptoms that affected me prior to taking up the diet have dispersed. This morning at the commencement of my second day I noticed upon arising and emptying my bladder that the volume passed was twice as much as was usual. My weight remains stable so I am presuming by consuming grains that they are inflammatory and by passing a larger volume of urine that grains may tend to retain water in the body. Tonight, at the end of the second day, my body still feels lighter.

    Emile Coue, the late French psychologist, stated that the law of reversed effort comes into play when one ‘wills’ oneself to achieve some aim; he suggests it is like challenging one’s self and that it is best to use less challenging words like ‘may’ or ‘wish’ or ‘I would like’. I have found this advice very helpful.

  7. Galina L. 8 June 2013 at 9:37 am #

    I found it much easier to eliminate whole food groups like bread and sugary deserts than to practice “moderation”. As a result I stopped looking at pastry or an ice-cream as food sources. I make an exeption sometimes for social reason when I visit other people.

  8. Tracey Greenwood 9 June 2013 at 11:31 pm #

    I would be very interested to know where I can get such ‘high’ doses of L-Tryptophan, as my Dr cannot prescribe it, and can only find 50mg tabs (at around £10-£15 per 120 capsules!).Thanks!

  9. Dave P 10 June 2013 at 7:14 pm #

    Havn`t needed any help reducing my carb intake, I can quite happily walk down the Cereal Bread Aisle and not bat an eyelid. Yes I do still have a roast tattie on Birthdays etc but it dosnt bring back the cravings.

  10. eddie watts 11 June 2013 at 2:45 pm #

    been low carb/paleo/primal whatever you prefer for a number of years.
    i literally do not crave any of those foods that we would consider “junk” or whatever term you prefer.

    i think the craving is a learned behaviour and we can learn new behaviours easily enough if we want to. (albeit with biochemical background too)

  11. Robert Park 12 June 2013 at 4:17 pm #

    Now into my sixth day of a grain-free diet (see comment above) I did not find the change difficult; it was simply a matter of remembering to be aware. The immediate impact was the feeling that the body, internally and externally, was lighter. This feeling has remained with me since. There was no eureka effect, yet as each day passed my energy levels increased and so did the feel-good feature. For the first time this morning I noticed that the bathroom scales moved fractionally to the left indicating a slight reduction in weight. I am not eating as much yet have increased the consumption of vegetables and fruit. I enjoy steaks with plenty of its fats but then this has always been the major part of my diet. Hunger is something I have not experienced during the week nor indeed the desire for anything made from grains. At this moment of time I feel ‘top-of-the-world’ so long may it last.

  12. Joseph 17 June 2013 at 10:46 am #

    If someone has a strong will power, and is not affected at all to see a restricted food in front of them then does it still affect the person negatively.

  13. SueG 17 June 2013 at 3:19 pm #

    I struggle with sweet carbs. I have pretty much given up pasta, rice, potato and bread and I don’t miss them. I don’t get hungry either yet I find my morning coffee a challenge. If we go out shopping then we have a coffee. I can resist any sweet stuff in an outlet like Costa because I am of the opinion that it’s all rubbish anyway but in, say, Waitrose, I am tempted and fall. As we only eat twice a day I tend to reassure myself that it’s just like having lunch but the effects are not, invariably my weight goes up.

    I have stuck to the low carb eating for over a year, I have lost only few pounds and am very disappointed. I don’t lack willpower but I do probably eat sugary things because I am not losing weight and think what’s the point?

    I know that weight varies on a daily basis for lots of reasons but how do you put on 3 or 4lbs overnight sometimes? This happens to my husband too. On our fast days we are juicing using recipes from Jason Vale. Whatever I lose after a day, it’s back there after a “normal” day. Do I have to be really ruthless and try to cut all sugary food out, or will this be pointless as noted in the article? I wish I knew the answer.

  14. Digby 21 July 2013 at 1:35 pm #

    I’m glad for those people who seem to have no cravings for carbs on low carb or paleo, and I notice this seems more likely for men than women; however, sluggish or low thyroid, insomnia, high stress, and other such conditions make carb cravings more likely and more intense. For quite a while I was apt to blame my cravings, while on a very low carb diet, as “psychological” then found I was dealing with low thyroid. It is important to get some tests if you are still dealing with strong cravings on low carb diets.

  15. Digby 21 July 2013 at 1:43 pm #

    @Joseph- You answered your own question, for if one is not affected, then ipso facto there was no affect. There will nearly always be a spectrum of results for anything, as in this case.


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