Food Cravings

Food cravings are defined as frequent intense urges to eat specific types of food. There are people who deny their existence, but in truth, we’ve all felt them, some more than others. For example, some people have intense food cravings for sugar (probably the most common). However, salty foods, chocolate, junk food (pizza) are also common food cravings. Gary Taubes wrote about carb addiction in last week’s New York Times.

We may know very well from an intellectual standpoint that eating these foods will make us gain weight, but feel helpless to resist. This is not really all that hard to understand. Consider a substance such as alcohol. Even as drinking destroys his life, the alcoholic addict feels compelled to drink. We understand that he is the victim of alcoholism and provide support to him to reverse it. For example, he might be encouraged to join Alcoholics Anonymous without stigma that he ‘let himself go’ or that he simply had no willpower.

Unfortunately, food cravings are not free of such stigma. If you are unable to resist the call of the donut, then many people consider it your fault, and help is much harder to find. Karen Thompson and Bitten Jonsson on www.dietdoctor.com have written about sugar addiction and help many people beat it.

There’s an association between obesity and food cravings, and the same holds for type 2 diabetes. The most consistent offenders are sweet foods, starchy foods, high fat foods, and junk foods. But does food craving lead to obesity or does obesity lead to food cravings or both? This is a very important question, because understanding the cause (aetiology) is the key to successful treatment. So, what causes food cravings?

One theory is that food cravings develop in response to deficiencies of certain nutrients or overall food energy (calories). There is no scientific data that suggests this is true. In the case of obesity, clearly these patients do not lack overall food energy. There are those who suggest that there is a nutrient deficiency that causes obesity. This leads to calls for eating nutrient dense foods. But, there’s a clear and obvious problem here. What nutrient are we talking about? In the case of most junk foods, sweet foods and starchy foods, there are no essential nutrients contained here, so the body cannot ‘crave’ these nutrients for good health. Coca cola has no essential nutrients. Donut have no essential nutrients. Just as with vitamins, obesity is not a nutrient deficiency syndrome. It’s not scurvy. It’s not kwashiorkor. 

The remaining possibility is that food cravings develop due to the consistent association of certain foods with particular stimuli or social contexts (special occasions). This suggests that food cravings are largely a conditioned response (like Pavlov’s dogs). If this is true, then part of the solution is to break these responses. That is, if we can stop taking certain foods for a long time, then those cravings should slowly improve. Is this true? Indeed, it is.

In this study, participants were put on a very low calorie diet – 1200 calories per day in the low calorie group (LCD), and 800 calories per day in very low calorie (VLCD). You can see that severe caloric restriction was much, much more effective at reducing cravings than a higher calorie diet. This is despite the fact that a 1200 calorie diet is already extremely strict. My guess is that even more severe restriction helped to break many of the conditioned responses where the more lenient diet was not powerful enough to do so. The same effect is seen in juice fasting diets where an approximately 800 calorie ‘fasting’ diet helped reduce cravings where low calorie diets alone could not.

This leads to the counterintuitive fact that we seen in our IDM clinic all the time. Eating less, when you go very, very low, makes you LESS hungry, not more hungry. If you have food cravings, then this effect is potentially very important. In the study shown, a 1200 calorie diet was virtually ineffective at lowering cravings where the 800 calorie diet reduces it by at least 50%.

This effect is seen for all different types of foods  whether it is sweets, starches, fatty foods or fast food. Over time, this effect does not diminish, but persists. Once you start refeeding, the effect starts to dissipate.

This concept extends to hunger. While cravings and hunger are different phenomena, they are clearly correlated to one another, so that decreased cravings can be expected to result in decreased hunger. But keep in mind that this effect is only seen with very severe caloric restriction. In fact, a comparison of a 500 calorie versus a 1200 calorie dieting schedule revealed significantly less hunger in the 500 calorie diet. That is, hunger is less, with less food. Counterintuitive, but consistent.

A more recent meta-analysis looked at this effect in more detail. Reviewing all 8 studies in the literature, they found that interventions lasting at least 12 weeks with caloric restriction consistently showed decreased food cravings. The effect is not huge, but consistent once again for all manners of food – salty, sweet, fatty, or junk foods. People who have cut out certain foods notice this, too. People who reduce their sugar intake very close to zero, for example, find that their sweet tooth goes away. If you eat more sugar, cravings don’t get better – they get worse. It’s like that itch – scratching it won’t make it better – it will make it worse.

The application to fasting is obvious. Severe restrictions on food do not increase food cravings, but consistently decrease them – which is one of the keys to success. This is entirely consistent with our clinical experience. Contrary to almost everybody’s expectation, fasting decreases hunger. Patients would always come back to our clinic and say “I think my stomach shrank. I eat a third of what I used to eat, and feel so full.”

That’s great news, because now you are working with your body to lose weight instead of against it. One of the persistent myths about fasting is that ‘you will get so hungry that you will be forced to stuff your face with Krispy Kreme donuts’. This is why people recommend that you eat 6 or 7 times throughout the day, in order to stave off those cravings. These people obviously don’t have any practical experience, and don’t understand the research which shows exactly the opposite. If you eat constantly, you are more likely to feed those cravings. If you fast, those cravings will shrivel away. Maybe. At least it’s worth a shot.

 

 

29 Responses

  1. Christian

    But does your stomach actually get smaller, or is it just the hunger that decreases?

    • I think it’s likely that the feeling of “fullness” of the stomach we experience is just our interpretation of what we feel, rather than a strictly mechanical fullness. Drink skim milk or heavy cream, you will very likely feel “stuffed” on a much smaller volume of heavy cream. There are stretch receptors on the stomach that keep us from doing damage, but when somebody’s losing weight on a high fat diet that’s very calorie-dense, it’s unlikely that they’re overstretching their stomach.

  2. This rings true with me. It’s taken three or four years, but I’ve now reached the stage where hunger is not a problem – just a gentle reminder that it could be time for a meal. I fast intermittently at irregular intervals and actually feel more alert and more energetic when I haven’nt eaten for many hours. I used to still crave old favourites for a year or two and just gave in whenever the craving became too strong but ensured it didn’t become a habit. Gradually the cravings lessened and giving in to them became less rewarding. I now feel more in control of my appetite and only have to worry about how to include all of the wide range of real foods that can be enjoyed on a low carb diet.

  3. I agree with what Dr. Fung says here, but I also believe that some foods (such as sugar, refined grains, and chocolate) release feel-good chemicals in our brains that honestly make us seek them out like a drug addict.

  4. With fasting there is less of a food craving. The answer as to why the 800 calorie diet had lower food craving is that it went from low-calories to the body’s response to fasting, and thus the craving was less. If they measured leptin and the other hunger and metabolism hormones you would find the answer. The body goes from putting the brakes on to conserve fat and increase appetite into the fasting mode which includes diminished hunger. In the video Fasting vs. Eating Less: What’s the Difference? (Science of Fasting) 13 min, 469,000 by What I’ve Learned at https://www.youtube.com/watch?v=APZCfmgzoS0&spfreload=10 this topic is developed: the low carb group had enough carbs to stay in the hungry mode.

    For a very large collection of documentaries and lectures with brief descriptions, rating and links to YouTube, go to my website at http://healthfully.org/rg/id4.html

  5. I’ve been doing Intermittent Fasting (IF) now for 2 1/2 months, after reading Dr Jung’s book. Now, I follow this way of living 95% of the time, with the occasional eating earlier, at say a family function, that I relax and have fun at. At first, I could NOT wait until 2 pm to eat. I was salivating at 12 and then again at 1pm. I’d have a cup of tea, can of seltzer, or cup of black coffee and what I thought was hunger pains, would immediately dissipate with just something to drink. Then I started to question, what is hunger anyway? Was I really hungry or am I just in the midst of breaking the habit of eating 3 squares a day, with snacks? Great lesson to figure out. Yes, I’m listening to my body now instead of being on auto pilot. Gradually the cravings go away and I’m even questioning those too. Who’s in charge here?

    Bonus, I’ve never felt better in my life. I’m energized, exercising every morning, focused, and love this way of living. It’s so simple that it’s ridiculous. I’m a Certified Health Coach and when I tell people that I’m doing IF they run in fear, think I’m the weirdo, and stop me right there, saying this isn’t for them. My family and friends think I’ve gone off the deep end too. I only eat NO processed carb, whole, fresh, clean, organic food so I’m the healthiest of all my friends and family. No medications, no illnesses, nothing to complain about other than the usual hang-nail.

    My point is, who cares what others think and do or don’t do. Do what feels right for you? Ditching food until 2 pm and then only eating dinner at 6 pm is perfect for me. I’m losing my muffin top, love handles, can now fit into my Size 8’s and feel fantastic! That’s what it’s all about, right?
    Thanks for listening! Stay positive! Sue

    • Isn’t it funny how you start doing something that works and every one wants to tell you that you are doing something radical and dangerous. I did 3.5 months of IF and LCHF and was only consistent 85% of the time. I lost 30lbs of fat and got muscularity wise very defined, stronger, and was able to run many miles while in ketosis at 40 hours fasted. The ignorance I once had On calories in and calories out is the problem I see in most other people. And to see people going months with no results yet these same people will criticize keto and intermittent fasting just shows they believe the popular lies about weight loss. Rarely do those people escape that lie and live a life less abundant. We can help these people. Because what I have seen since losing the fat and getting more fit is some of those people will act like they never talked negatively about your way of eating and as of you did not lose any weight. But others will change their mind after asking more about it and wanting the freedom we experience. I try not to burn bridges so as to later maybe help the few that swallow their pride and seek the truth about these things. The answer for me is LCHF and IF up to 40 hours a couple times a week and 20 hours all other days with some weight training a couple days a week and running on the longer fast days. I have my favorite foods. It just gets easy after you make the shift.

    • It is an epiphany that EVERY individual must go through; it strives at the core of our existence.

  6. Junk food tastes good. Getting intoxicated feels good. Sex feels good.Pleasure that comes from sense contact is addictive. Whatever feels good we crave. Whatever we crave, we cling to. The Buddha prescribed mindfulness, ethical living and practical wisdom (from the mindfulness) to counter addiction. It has worked (relatively) well for me, but I am by no means cured. I still love and crave crappy foods, but I am learning to cope with the addiction.

    In a way alcohol is easier than food because one can permanently quit drinking, but one cannot stop eating indefinitely.

  7. Diet Coke was my obsession. The first year I still had desires but after two years there was almost no desire. Now 10 years later, there is the opposite reaction, I almost have a negative reaction. I am trying to apply the same approach to alcohol, especially beer, however the social association is much harder. But the result is the same, year after year the desire is much less. Perhaps it’s my age, now 65 years old, but I feel it’s the application of abstinence.

  8. Dr. Fung,

    Dropping the knowledge bomb as usual!

    At the risk of being a pedant (and yes, annoyingly so), would it be possible to correct “theory” to “hypothesis” in

    “One theory is that food cravings develop in response to deficiencies of certain nutrients or overall food energy (calories). There is no scientific data that suggests this is true.”

    All too often, scientific denialists and alternative fact purveyors, discredit scientific consensus by the claim “It’s just a theory!” i.e. climate change denialists and anti evolutionists. As this hypothesis has no validity, I think it is important to not credit it with the honour of being called a theory.

    Thank you for your brilliant work! It has made a tremendous difference in my quality of life!

  9. Good article Doc.

  10. What if I’m craving something good, though? I started a 36 hour fast yesterday and I feel fine. Went out to do a little gardening and saw all these lovely dandelion leaves that made my mouth water. In my family we simmer the leaves and eat them, along with their broth, with garlic and oil.

    If I simmered the leaves and just drank the broth without any oil, that wouldn’t break my fast, right? I think I might just be wanting the minerals.

  11. Christine E.

    Great post Dr. Fung! I hope someone investigates this as a strategy for dealing with non-food cravings/addiction. My uncle struggled to quit smoking, post mealtime being his biggest challenge. His solution was to simply stop eating entirely till the craving went away. Ten days later he started eating again, completely free of his cigarette addiction.

    • Fasting is the way many people overcome addiction to drugs. Awesome about your uncle.

  12. Monore S.

    How about starvation mode? I mean we basically have to eat about 1200 calories to maintain our daily activities (as least this is what we have been told & taught) What if we keep eating less than 1200 calories?

    I didn’t feel hungry at all when I started my fasting, eating few bites every meal makes me full already. I ate less than 1000 calories per day.
    But then my friend warned me, I have to eat more since I still have quite a lot of weight to lose (S.W.256, G.W.110) and prevent myself to get into starvation mode.. then I forced myself eating more.
    It back fired, I started craving for carbs and sugar and getting hungry all the time, which didn’t happen since I started my Keto.

    So to kill our cravings, we have to eat less. But would it cause starvation mode?
    Will we eating lesser and lesser then?

    • If your body has lots of excess stores energy then in order for you to not starve yourself you must stop eating carbs and get your body to switch over to fat burning mode. Your body will eat your stores fat and therefore you are not starving your body but in fact are using much more calories than normal because in ketosis your body also wasted stores energy through urination and respiration. You need to understand this concept in order to understand the difference between starving more and fat burning or ketosis mode. There is a big difference and people that starve themselves by eating just enough carbs to stay in sugar burning will just screw up their metabolism even while losing weight. But it will come back and the end result is usually worse than the start.

    • You should search the site for “starvation mode”. There are a lot of myths about starvation mode that simply are not true. You might start here:

      https://intensivedietarymanagement.com/fasting-myths-part-5/

  13. “One theory is that food cravings develop in response to deficiencies of certain nutrients or overall food energy (calories). There is no scientific data that suggests this is true.”…… I tend to disagree with this statement, as there is plenty of scientific data, IF one is willing to pull back the green curtain in the land of oz…… http://www.drlwilson.com/articles/copper_toxicity_syndrome.htm (references at the end of the article and within the references referenced 😉 😉 )

  14. I think the great philosopher Yogi Berra stated the proper notion: “‘Baseball is 90 per cent mental. The other half is physical’”, so: Cravings are 90 per cent mental. The other half is physical.

    I’ve read responses above about Buddhism, and evolution, and being bad-person deniers of evolution and climate change. What???!!!

    How about being true honest seekers of truth? Buddha will not make you less craving of bad foods, and I can assure you that that is not Jesus’ purpose for your life either. The real connection of religion or world-views and diet is: objectivity. Take a step back, and begin reading everything with an objective mind. Easier said than done. But do it! Be honest with yourself – perhaps you do not know the truth, yes?

    And so we all must learn. Step #1, admit your ignorance. Step #2, seek help in learning.

    So, with cravings, step back and think about it. You want to eat that donut not because you are hungry, but because it will taste good, and maybe you know the sugar rush you’ll get, albeit briefly! You’re maybe tired, stressed, whatever – you think the donut will bring relief. Hunger? What’s that?

    Step back, objectivity – “that donut will set me back”. Resist the temptation 🙂 After you work at it, that donut craving should turn to donut disgust, because you now associate the real good stuff (see JenP above). And maintain objectivity – have I eaten a barrel of dandelions today? Balance. In those cases of distress, the real “food” you may need is spiritual, and for that I humbly refer you to the Word that became flesh, Jesus Christ – you can eat His flesh and drink His blood by: reading the Word, aka Bible. Peace.

  15. Thanks for another great post, Dr. Fung.

  16. thebigpicture

    I personally have found chocolate to be the hardest to give up. I can give up other sugars for some time but not chocolate.

    The food addicts and obese are right in one way alone. They will say, that food is their one and only craving. That they aren’t smokers, drinkers, drug addicts, etc. And in this sense they are right. But this attitude can also be dangerous, because it blinds them to something that was creeping up on them from a distance and then will eventually blow up in their face.

    Society shifting so much blame and attention to drug addicts has taken attention away from food (and perhaps even tv, internet, etc. though this is a separate question).

    • I feel for you, brother.

      I can go with no sugar without breaking a sweat, but eschewing chocolate (and beer, but that is a different tune altogether) made me deeply unhappy.

      I found the answer in pure cacao, be it powder or directly cacao beans. Only for very dark chocolate lovers, though

  17. It really is much easier to understand and help a person addicted to alcohol than a person who can not control themselves in front of some food, these people suffer especially if it is a woman, because besides being guilty still suffers with insinuations about its silhouette the Which causes more suffering and aggravates the problem.

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