Tuesday, July 7, 2015

What Properties Make a Food "Addictive"?

Although the concept of food addiction remains controversial, there's no doubt that specific foods can provoke addiction-like behaviors in susceptible people.  Yet not all foods have this effect, suggesting that it's related to specific food properties.  A new study aims to identify the properties that make a food "addictive".

Introduction


Common sense tells us that one of the reasons we eat too much is that we're often exposed to food we find extremely seductive.  In common parlance, we refer to these foods as "addictive", which may not be too far off the mark.  A growing number of researchers propose that some of us really are addicted to certain foods, via a process that resembles drug addiction.  In other words, certain foods can exert such a strong pull on our motivational systems that they cause us to make decisions that are self-destructive*.

To define food addiction, Kelly Brownell and Ashley Gearhardt designed a tool called the Yale Food Addiction Scale (YFAS) (1).  It's a questionnaire that's based on established diagnostic criteria for other types of addiction, and the authors describe it as "a sound tool for identifying eating patterns that are similar to behaviors seen in classic areas of addiction".  Brownell and Gearhardt's research shows that many people exhibit behaviors toward food that resemble drug addiction, and that this addiction-like behavior is more common among binge eaters and people with obesity (2).  They argue that food addiction is a real clinical entity and should be treated as such.

Yet, people virtually never get addicted to celery and lentils.  They get addicted to junk foods, the same foods that exert a strong pull on most of us-- even if we aren't quite addicted.  What is it about junk foods that has this effect on us?

The study

Gearhardt and colleagues recruited 120 volunteers and had them complete a questionnaire that asked them to rank the "addictiveness" of 35 different foods representing a broad spectrum of nutritional values (3).  Some foods were unprocessed and low in calorie density, while others were highly processed "junk foods".

The results

As expected, highly processed foods were rated as most addictive.  The top seven most addictive foods were:

  1. Chocolate
  2. Ice cream
  3. French fries
  4. Pizza
  5. Cookies
  6. Chips
  7. Cake
Also as expected, unprocessed foods low in calorie density were rated as least addictive.  Here are the bottom seven foods:
  1. Bananas
  2. Plain carrots
  3. Plain brown rice
  4. Water
  5. Cucumbers
  6. Broccoli
  7. Beans
When they analyzed the nutritional qualities that were most closely associated with addictive ratings, they found that fat content and glycemic load were strongly associated with addictive potential.  

Interpretation

Since food was such an important part of the survival and successful reproduction of our ancestors, the motivational systems in our brains are highly attuned to it.  The brain receives information from sensors in the mouth and small intestine that measure the nutritional value of what we eat, and it sets our level of motivation to eat each food according to its nutritional value (mostly its calorie content).  This process involves dopamine release in the nucleus accumbens, just like everything good in our lives, including sex, hitting a home run, and getting a raise (4).  

Yet too much dopamine makes us too motivated, and this is the essence of addiction.  When a stimulus increases brain dopamine too much-- such as crack cocaine flooding the nucleus accumbens with dopamine-- it causes an unnaturally strong motivational state that can lead to destructive decisions.

Gerhardt and colleagues found that the most "addictive" foods are processed foods high in fat and with a high glycemic load.  Consistent with findings from other areas of research, this suggests that we're particularly drawn to foods that deliver concentrated calories that are easily and rapidly digested.  Gearhardt explains that this scenario parallels key properties of drugs of abuse:
The current study provides preliminary evidence that not all foods are equally implicated in addictive-like eating behavior, and highly processed foods, which may share characteristics with drugs of abuse (e.g. high dose, rapid rate of absorption) appear to be particularly associated with “food addiction.”

To someone who is familiar with food reward circuitry, this is no surprise.  The brain systems that mediate learning and motivation respond to specific food properties**, and when we eat foods that deliver unnaturally concentrated combinations of those properties, the brain produces an unnaturally strong motivational state.  In some people, that state can be so exaggerated that it resembles drug addiction.  In the rest of us non-addicted folk, it just makes us eat too much.


* I think if we were really honest with ourselves, we would recognize that most people in affluent nations like the US make self-destructive choices about food, due to the motivational pull of certain calorie-rich foods.  We know many of these foods are unhealthy, yet we (over)eat them anyway, and they end up making us sick and limiting our mobility and enjoyment of life.  This satisfies the core diagnostic criteria of addiction: repeatedly engaging in a rewarding behavior despite serious, known harmful consequences.  Frankly, I suspect the main reason we're resistant to classifying this behavior as addiction is that we don't want to admit we have a major, widespread problem with our eating behavior.

** These include carbohydrate, fat, protein, salt, sweet taste, glutamate (umami) taste, and calorie density.

35 comments:

aluchko said...

Has there been any research on the perception of food availability on hunger, addictiveness, and obesity?

I ask because I noticed that when I'm travelling or particularly backpacking, and am in a situation where I perceive food as something to be conserved, I end up being drastically less hungry. But if I'm in a scenario where I perceive food as essentially unlimited, buffets in particular but really anytime with a full fridge, then I no longer feel the need to conserve food and the only constraint is my own hunger.

This does make sense as a mechanism from an evolutionary perspective. If you're in an environment where food is scarce or needs to be conserved then you don't want to have a lot of hunger and eat everything in sight, people are aware of the status of their food supply so I think the brain is perfectly capable of managing this mechanism itself.

Have people looked at this as one of the mechanisms for obesity in industrialized cultures? If you're dependent on a harvest or hunt even when there's plenty you're always aware you might need to conserve so you'll naturally be less hungry to conserve food. But if you're aware your food supplies are essentially endless you'll eat as much as you want.

SamAbroad said...

Yes the resistance to admit that a compusion to eat rewarding food can reach addiction levels is strong in western culture.

We have long associated food with morality/righteousness (kosher/halaal/fasting during lent).

Why we can't acknowledge that some people use food to lessen pain like other people use drugs, cigarettes and alcohol do?

Drugs, alcohol and cigarettes are highly regulated/prohibited to varying degrees but especially the marketing.

Food marketers have no such restrictions. So are free to try and thwart the efforts of addicts to abstain at every step.

Also there are people who will never get the same reward from chocolate that others do and can take it or leave it, it's very hard to convince people like that of the hold some foods have on people's emotions.

Gretchen said...

I'm addicted to roasted, unsalted almonds. Other nuts won't do.

I think the appeal is the crunch and the fact that they're hard.

Stephan Guyenet said...

Hi aluchko,

The brain to large extent is an economic calculator and food availability is part of the value function. When we have lots of easily accessible food, that titillates the regions of the brain that respond to economic value, and we end up eating more (and vice versa). I don't know how much it has to do with reward itself, but it does affect our food intake. I'll be covering this in my book-- really fascinating stuff.

FredT said...

I would bet that anyone more than 100 pounds overweight is dealing with addiction, and further it is likely sugar and wheat based carbohydrates, or other processed carbohydrates. As the range of overweight reduces, addiction is less common, based on my observations. Maladaptive behaviors where eating is the maladaptations would next. This includes stress, anxiety, indecision, frustration, no logical choice, trapped in abusive situations, living under a control freak, etc, but then I know nothing.

Robert said...

Is this the first announcement for your book, or did I miss something? When is it coming out? What's the topic? I can't wait to read it.

I'm also a believer in the food "addiction" concept, although maybe we should follow DSM V and call it a "use disorder" instead. Would you consider a blog post outlining why some people don't agree with the food addiction concept while others do?

Sharon McCormack said...
This comment has been removed by the author.
Stephan Guyenet said...

Hi Robert,

Thanks. I've mentioned it a couple of times in podcasts, etc., but I suppose I've never really made a formal announcement. It's titled "The Hungry Brain", and it's all about the neuroscience of overeating. It focuses on explaining why we overeat even though we don't want to, and to some extent, what we can do about it (not a diet book). It's a deep dive into the brain for people who love science.

I'm extremely excited about the book. I've interviewed 30 top researchers so far, in a variety of areas of neuroscience research, and I've got about 20 more to go. Although some of the topics will be familiar to WHS readers, the book will go far beyond what I've written on this blog. There really is nothing like it out there right now. It will probably be on shelves in late 2016. It will be published by Flatiron Press, a division of Macmillan.

Gretchen said...

Will you discuss why crunchy foods are so appealing?

We seem to like both very smooth foods like smoothies and mashed potatoes and very crunchy foods like potato chips and crackers. The former could remind us of early childhood, and the latter could remind us of our carnivore ancestors crunching bones. I always enjoy crunching the bones at the tips of chicken wings.

Stephan Guyenet said...

Hi Gretchen,

I don't know why crunchy foods are so appealing, but here's my guess:

1) Crunchy foods usually have a very low water content, which means a high calorie density. We're innately drawn to foods with a high calorie density.

2) Crunchy foods are easier to pulverize with the teeth than stale non-crunchy foods; the crunching is the sound of the food shattering. We probably are able to extract more calories from crunchy foods because they pulverize more easily/thoroughly.

The second part should be testable.

aluchko said...

3) Crunchy foods are fun! (I find the act of manipulating hard crunchy foods in my mouth so I can safely eat them to be fairly enjoyable)

Since having the thought about scarcity and hunger I've actually tried thinking of food as a scarce/valuable resource and dropped about 2kg fairly quickly, but I'm not sure if it's a sustainable strategy when food is so obviously cheap and plentiful. I think the worst is when I have a food supply that's been around for a while, want to get rid of it, and get hungry as a result.

It's nice to head about the book, I'm looking forward to it.

Joellen C said...

I have observed my own food addiction with an open and curious mind for the past year or so. I have never had an addiction to street drugs or alcohol, but I do therapy with teens who do. When my young clients describe their struggles to regulate difficult emotions without their substance of choice, I can really identify. With or without the scientific evidence, I have an intuitive understanding that my 'food addiction' is similar to their drug addiction. Becoming conscious of how I regulate my own emotions has been helpful in gaining insight into why I turn to food for comfort. But even after reading some good books on emotional eating, it hasn't helped me stop. If I buy a bag of kettle corn, it might as well be a drug. If I eat plain salted popcorn, it is easier to stop. The sugar/salt/fat triad is notorious, & I have no doubt that to my brain/body chemistry, it is like a drug. Emotional eating is not the same as addiction - I have read several good books on that topic, and the only way to not binge on kettle corn is to not have it in the house. Given the neuroscience of addiction, I think it will be helpful for research based weight loss programs to include various elements to support people in creating healthier eating habits, including decreasing food reward, enjoyable exercise, mindful eating tools, and alternative ways to soothe strong emotions. I look forward to reading your new book when it comes out!

Gretchen said...

Re (1): This doesn't explain my attraction to pickle cucumbers fresh from the garden (they also have a satisfying small crunch). And most people like watermelon. I assume that like so many things in this field, attraction to different foods is multifactorial and differs from person to person.

Peter said...

Another part of addiction is one's opinion about what to if you are a little bit hungry. If you know that feeling will go away you are less likely to eat than if you think it makes sense to eat to make the feeling go away. I learned from intermittent fasting that if I am a little hungry, the feeling goes away if I don't eat.

Chris L said...

This fits in with my experience. I don't know that I'm addicted to food but I am as likely a candidate as anyone. I've battled morbid obesity my entire adult life and currently weigh 400 lbs. I started the Ideal Weight Program two weeks ago and did well at first but then I devolved to mostly tracking calories via MyFitnessPal while trying to mostly choose simple foods.

What has killed me is my cravings for a burgers and burritos. I know what it's like to want to eat something (I could eat pizza every day) but that desire is nothing like the cravings I have for burgers and burritos. It is literally an overpowering compulsion to seek out those foods. It overrides all of my rational thought processes and good intentions. My burgers are 80/20 ground chuck and Rainbow hamburger bun while my burritos are eggs, sausage, cheese and fried potatoes wrapped in a huge white flour tortilla. A perfect storm of fat and high glycemic index foods.

Despite all that, I have still dropped 15 pounds in 15 days by strictly sticking to my calorie limit while trying (sometimes in vain) to primarily eat simple foods.

We are leaving tomorrow for a week long vacation and I'll continue to adhere to my calorie goals but once we get back and I go back to work, I plan to really jump back into the simple foods.

ICG said...

This just came out on crunchy food:

https://www.yahoo.com/food/the-scientific-reason-why-crunchy-food-beats-soggy-122800519072.html

Stephan Guyenet said...

Hi Joellen,

Thanks for sharing. We are thinking hard about ways to combat the pull of highly rewarding foods for the Ideal Weight Program. It's a hard thing to beat because it's a deeply seated, strongly reinforced habit. There was some recent work that I found quite intriguing showing that people can reduce their motivation toward highly rewarding foods by subconsciously associating them with unpleasant images in a research setting. This is a milder form of the same principle applied in "nausea aversion therapy" used to treat alcoholism. The idea in both cases is to create a new, negative association to combat the strong positive one, which reduces motivation for the reward. I think the main limitation is the question of whether consumers would find this type of approach acceptable.

Hi Chris,

Thanks for sharing. Sorry it's a struggle. Your cravings should become easier to control over time if you don't succumb to tempting foods. Glad you're losing weight and good luck going forward.

Unknown said...

@Stephan

That's the "therapy" applied in A Clockwork Orange to treat the violent behavior of the main character ... not really appealing ..

R said...

I think there's a further resistance to calling food addictive because some of us know people who have been addicted to drugs and it just seems *different*. I don't mind food being on a continuum of addictiveness, but I found all those articles in the media a while back making a direct comparison between sugar and cocaine a bit upsetting.

Matt Lentzner said...

Glad to see that we are getting more confident in calling this disordered eating an "addition". I'm just a layman, but I couldn't see how it was any different from any other additive behavior. I think this is the reason why people are unhealthy, macro content, cholesterol, sugar, etc, don't matter except to the extent that they encourage the addiction.

It's particularly pernicious since you can't not eat. Of course you can no eat the junk, but you have the food companies constantly muddying the water with 'health' food like granola bars, fitness bars, wheat bread, etc. I don't have this addiction, but my sympathy goes out to those that do.

As a parting shot, I don't consider chocolate to be addictive, but I eat the 85% cacao stuff. Milk chocolate isn't chocolate, it's candy.

Stephan Guyenet said...

Hi R,

Good point. I think there are people whose lives are severely diminished by their food choices, but it's not exactly krokodil.

Hi Matt,

I agree, in common parlance we call certain foods addictive and I think there's some truth to that common sense perspective. Personally I find dark chocolate (85-90%) very compelling and I have to watch myself around it. I can pass on milk chocolate.

v/vmary said...

during pregnancy, iron deficiency, etc people are known to get cravings for certain foods based on a need for a nutrient. lately i have been eating sour/spicy things. i mix plain greek yogurt with salsa, mustard, and red onion. do you know if there is any research on craving that sort of thing? i know i am not pregnant. also, i used to crave cheese, but now it just tastes fatty and oily to me, not like before when i was eating chunks of it.

kateR said...

I wonder if something else may be going on when it comes to hunger. I'm a lifelong lean person. When young I could (and did) eat large amounts of starches and sugars. Every morning I'd wake up and have to eat breakfast IMMEDIATELY. Waiting for a late-sleeping partner was torture.If I had really overindulged the previous evening (supper followed by a giant piece of cake and a big sweet cup of coffee or two) then I'd wake up not just hungry, but famished. As a middle-aged person,I've kicked the sugar and starch habit, largely, but notice on the rare times I do eat those carbs, that compelling hunger is back. Makes me feel for those people who put so much effort into limiting their caloric intake, if they feel that kind of hunger!

Jaime Fivecoat said...

I'm a facilitator of a SMART Recovery meeting, and we see folks come through for food addiction all the time. We view addiction as any habitual behavior that results in outcomes that interfere with or destroy our ability to support or achieve our core values. For those that come to a meeting, over eating the wrong foods usually causes or exasperates issues with health, relationships, employment, physical ability to do activities they want to do, financial stress, and many other personal issues also associated with substance abuse or process addictions.

Another good resource on describing this issue and relating food addiction to other addictions is the "The Compass of Pleasure", Dr. David J. Linden, 2011.

Thanks for this post Stephen, it's very timely for me as I'm doing a lunch table discussion on food addiction at this year's Your Weight Matters 2015 #YWM2015 convention in August.

Jaime

blogathon said...

"I suspect the main reason we're resistant to classifying this behavior as addiction is that we don't want to admit we have a major, widespread problem with our eating behavior."
Another reason I suspect is that this could leave food companies susceptible to litigation. Philip Morris owned Kraft for a while and there are parallels with the tobacco industry in that these companies have knowingly produced harmful addictive substances. As we know the tobacco industry was guilty of deliberately obfuscating lung cancer research by releasing papers that seemed to question the link, in the same way now we have quack nutritionists that gain huge amounts of publicity such as William Davis, Taubes, Teicholz, Atkins etc. As long as people think that "carbs" are bad or fat is bad and don't concentrate on the addictive properties of the combinations of salt sugar and fat then the industry can keep churning out it's addictive processed junk.

lisao said...

Hi Stephan. I have been trying your low palatability low reward diet for several days now and it is having amazing effects on me. My hunger level has become very low yet my energy is up. Before if I didn't eat above appetite I would have symptoms of fatigue and low metabolism/hypothyroid types symptoms, cold, cold hands and feet etc. At night I would often feel awake and like my sumpathetic nervous system was reving not wanting to slow down and let me sleep. My heart would pound and I would have trouble sleeping or would wake up and not be able to get to sleep about 3 am.
In a very brief time your diet has brought all this to a halt. I'm feeling warm, energetic, sleeping well and have energy.

This is doing something very profound to my brain and endocrine system. I had gained quite a bit of weight and couldn't lose. Now clothes a feeling a tad looser. Just thought you would like another story about an experience with your recommendations.

Stephan Guyenet said...

Hi Lisao,

Glad to hear it!

lisao said...

Will follow up later on how it's going after some more time. I'm grateful the light bulb went on and I decided to try out your ideas. I have read your blog off and on for some time but for some reason I didn't really fully understand that the low reward palatability diet was not just about not wanting to eat as much because food doesn't taste good but that it actually changes what is happening in the brain and endocrine system. I'm looking forward to your book as I'm interested to understand how it works. I think I must be one of the people you write about who are very sensitive to reward factors in the diet. I can always remember highly rewarding foods causing me to binge and having a huge struggle not succumbing. Fortunately I must have a high enough metabolism that I've never had a huge weight problem even if I eat all I want, but I would like to lose 30-40 lbs that I gained having children.

Trying your diet recommendations has made me realize that when I eat highly seasoned and flavored food my body responds by upping my hunger and turning down my metabolism. I'm wondering if this is something inherent within my genetic makeup or is it something broken that might repair if given time without that stimulation.

Unknown said...

@lisao

You talk about brain and endocrine system, but you should not forget your gut! If you feed your gut flora with simple foods such as rice, legumes and potatoes without condiments, you quickly reach satiety and the gut flora will not starve, it will actually thrive. This will influence the brain / hunger to some extent. The gut flora aspect is an important factor in all this.

dianna said...

If I eat a simple diet and just have an occasional special treat of Ben &Jerry's Americone Dream is that acceptable? Or will that just mess up any progress I have made? No kidding, we have to go out for ice cream or
Buy the pints. If I know it is there I will not stop.

TomP said...

It's my first time to your blog--very interesting so far. I'll be back, and appreciate the communication of your research to a non-academic audience.

MBagley said...

A year ago, was " addicted " to pasta, chips and chocolate. These were my " pick me ups " when energy was low. However, the horrible feelings in my gut after eating these things ( over eating them ) , was so terrible. I started to do research. now reach for a banana, grapes, walnuts , almonds, and for those intense chocolate cravings which now only happen once every couple of weeks or so, chocolate whey protein with 100% cacao and stevia does the trick with no gastric distress. cravings are gone, addiction is gone, gastric distress is gone, energy needs are easily met this way. No desire to go back even if they are in the house for other family members. For me, finding out the reason for eating the "junk" , which was a feeling of low energy, and finding acceptable substitutions solved the eating problem.

voodooville said...

You have a nice blog on food. I tend to agree with those who believe that we are addicted to food that is deficient in some way. We don't get addicted to hiking in the mountains, because it is a wholesome experience. Video games are visually stimulating, but take away many other things - the physical movement, smells, touch, and natural patterns in a real environment. Same thing with Facebook, or rest of internet. Which makes them addictive.
Once we go back to food that is wholesome, i.e. traditional food, prepared with human effort, not manufactured food, a good deal of addiction, and obesity will go away. Thanks for your articles on sprouting, and fermentation, was searching about sprouting and nutrition, and got here.

Jennifer Haden said...

Very glad I've come across your blog, reading through it the past week or so, I can definitely agree with many of your conclusions from my own experience. Between my husband and I, we lost around 400lbs and have managed to keep it off for the past 3 years without struggle. We did this by kicking out all processed foods, anything with additives, just buying one ingredient items that are found in nature and eating simply. I noticed the more nutrient dense an item and the more water content, the more satisfied I felt/feel. The only fats we use come from oily fish, avocado's, nuts. There's no hunger now, we just get what our bodies need, that's it. And even though they are simple foods, we actually love them and get alot of pleasure out of them. So simple doesn't mean boring and tasteless, just means we have to let our bodies adjust to a more natural way of eating, the way nature intended.

Ruth from Belfast said...

Hi, I seem to be coming to the same conclusion about food and addiction backwardly. My weight is fine, as far as I know I had no burning food addictions (chocolate gives me headaches so I don't eat it anyhow). But I have been struggling with asthma and allergies and feeling as if I have been losing the battle for over 2 decades, also tiredness, not much confidence in myself, a general feeling of reclusiveness and not fitting in, and life always being such a struggle. I decided to try autoimmune elimination Paleo diet (thank you Sarah Ballantyne!) to see if I could get some relief from the asthma (not asking for any more than that!). I nearly wept when I realized what I had to give up, and I have been on the Paleo diet without cheating for 2 weeks now. I feel as I have stepped out of a fog that I have been in for decades. The asthma (so far) has not troubled me a bit. But the amazing thing I am finding is that I feel alert, clear headed, full of energy, and happy. I joined a choral group I could sing and breathe so well again! Well, what was with all the sorrow about giving up milk, eggs, nuts, wheat, grains, legumes, nightshade foods (tomatoes, etc.)! Every day I miss them less, and the foods I eat taste wonderful without trying to alter flavors or invent new ones. My plates of food are absolutely beautiful with color. I REALLY feel as if I have just understood that I have been struggling with an addiction and its physical and psychological damage, and I don't want to go back there. The amazing relief of being able to breathe, and the clarity of perception and energy I now have makes me want to be this way forever. Hope this little story helps the thinking about food addiction in general! Cheers, Ruth