Should obesity be classified as a brain disease?

Many of our most popular stories are about diets and weight management.

Did you know that some psychologists and psychiatrists would like to classify obesity as a brain disease? The reason for this is that there is mounting evidence that food, or certain types of food, can trigger the same addictive effects in the brain as drugs like heroin and cocaine. There is also substantial evidence that some people lose control over their food consumption and exhibit other behaviors (e.g. tolerance, withdrawal)  that may meet diagnostic criteria (see below) for substance dependence.

Laboratory scientists have used animal models borrowed from drug addiction research to study food addiction. In one study, rats were given access, not to cocaine or heroin but rather to a “cafeteria-style” diet including bacon, sausage, cheesecake, pound cake, frosting and chocolate.  As a result,  some of the rats became compulsive eaters. Compulsiveness is considered a hallmark of addiction in humans.

Psychology researchers at Yale University have developed a written test to identify people who may suffer from food addiction. The scientific background of this work is described in this video on UCTV.

Here are the diagnostic criteria for substance dependence according to the American Psychiatric Association’s Diagnostic and Statistical Manual of Mental Disorders.

Substance dependence is defined as a maladaptive pattern of substance use leading to clinically significant impairment or distress, as manifested by three (or more) of the following, occurring any time in the same 12-month period:

  1. Tolerance, as defined by either of the following: (a) A need for markedly increased amounts of the substance to achieve intoxication or the desired effect or (b) Markedly diminished effect with continued use of the same amount of the substance.
  2. Withdrawal, as manifested by either of the following: (a) The characteristic withdrawal syndrome for the substance or (b) The same (or closely related) substance is taken to relieve or avoid withdrawal symptoms.
  3. The substance is often taken in larger amounts or over a longer period than intended.
  4. There is a persistent desire or unsuccessful efforts to cut down or control substance use.
  5. A great deal of time is spent in activities necessary to obtain the substance, use the substance, or recover from its effects.
  6. Important social, occupational, or recreational activities are given up or reduced because of substance use.
  7. The substance use is continued despite knowledge of having a persistent physical or psychological problem that is likely to have been caused or exacerbated by the substance (for example, current cocaine use despite recognition of cocaine-induced depression or continued drinking despite recognition that an ulcer was made worse by alcohol consumption).

So what do you think? Is obesity a disease of the body or the brain (or both)?

Michele Berman is a pediatrician who blogs at Celebrity Diagnosis.

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    Eating highly processed foods is a way to alter the chemistry of the body. Instead of making another “disease” and finding more “drugs” to cure it, I propose we change what we are growing and what we are putting on our grocery shelves, in our refrigerators and on our dinner plates to work with the human physiology instead of against it. The acceptance of highly processed, sugary foods as a major part of our dietary sources is the problem, not a lack of pharmaceuticals. Efforts put into the direction of solving the root problem instead of “diseaseifying” it is a better use of resources. It is obvious the human body has not changed dramatically in the last 50 years-genetically speaking- but our diets and activity levels have. There is the problem.

  • Carolyn Thomas

    Thanks for this, Dr. Berman.

    If you’ve read Dr. David Kessler’s work, you’re more likely to buy this Yale thesis. The Harvard-trained doctor (and lawyer, former Yale Medical School dean and commissioner of the U.S. Food and Drug Administration) also believes that this junk food combo – salt-fat-sugar – actually stimulates our brain to crave more, just like an addict’s brain does.

    I recommend Dr. Kessler’s fascinating book, “The End of Over-eating”, which claims that foods high in salt, fat and sugar alter the brain’s chemistry in ways that compel people to over-eat. “Much of the scientific research around over-eating has been physiology – what’s going on in our body,” he said in a Washington Post interview. “The real question is what’s going on in our brain?”

    So if there’s any truth to this brain disease/addiction theory, how are we to kick the habit? Dr. Kessler believes that what’s needed instead is a perceptual shift, similar to society’s shift around cigarettes – arguably far more addictive than junk food.

    He writes: “We did this with cigarettes. It used to be sexy and glamorous, but now people look at smoking and say, ‘That’s not something I want!’ We need to make a cognitive shift and change the way we look at food. Instead of viewing that huge plate of nachos and fries (or chocolate-covered bacon) as a guilty pleasure, we have to look at it and say, ‘That’s not going to make me feel good. In fact, that’s disgusting.’ “ More at “Chocolate-Covered Bacon And Other Ways To Alter Your Brain Chemistry” at

  • SmartDoc

    It is a brain disease, and an amazingly complicated protean one at that, about which we know very little.

    I have great sympathy for the San Francisco Board of Supervisors, who received vast scorn for “banning the Happy Meal” (not at all what they did). This is the sort of public health measure needed to fight this horrific epidemic.

  • Dr D

    I am an overweight physician. I have gradually lost 45 lbs over several years. I have tried everything, but the final insight was something I read somewhere “If you’re not hungry enough to eat an apple, you’re not hungry”. Carbs cause you to secrete serotonin, which is a way of self tranquilizing. If I were a rat stuck in a cage in a crowded lab, I’d self tranquilize, too.
    But what has been interesting, is that as I have lost weight, my patients have,too. They have lost the excuse not to try.
    I am sure that I am genetically predisposed to hold onto weight, but ultimately it’s my choice. I think the information about what’s in what we eat is important. I think demonizing the happy meals are ridiculous-I bought them for my kid once every couple of months, max. She survived, and is not overweight. The real issue is what you do with your kids, every day. There should be acces to good food-but what’s the big deal with packing your own?I bring apples to work, and good snacks. I know staff will bring in junk, I need to be disciplined to bring in alternatives.
    If you cook at all, and I am a good one, you know that a mix doesn’t save you that much time, but adds a lot of sugar/salt. But with the economic downturn, I discovered that my staff didn’t know how to make the simplest of things-
    they had been brought up by Betty Crocker, and frozen stuff.
    It’s not just the food, it’s the accumulation of stuff we don’t do-I remember my great grandmother whipping cream by hand,and the wringer-washer, We don’t even get up to change the tv channel. Our area is an accumulation of strip malls, not the town center where we used to live, where you parked your car and walked down the street from the bookstore to the post office, Instead we have the mall, and it seems that even though there is the separate food court, there is something to nosh every 5 feet.
    l find it silly that you go to the gym to walk on a treadmill-it’s part of the reason that no one knows each other in the neighborhood,no one bumps into each other naturally.It’s not the food itself, it’s a cultural shift. Your go to the movies, and are given a ridiculous size of popcorn. But the activity involves sitting, and mindless eating.
    Plant tomatoes and cucumbers in your backyard or porch-they are weeds, and do fine in pots.. It’s relaxing, and very cheap. It’s an activity that helps your budget, and, well ,is not sitting and eating.
    And in this economy-why all the take out, or food for the microwave-cook ahead for the week, but healthily. It’s cheaper, involves a lot less plastic, and not that much work, when you start to account fot the amount of time you spend finding a parking space, at the checkout counter, or waiting for takeout. f
    On days I find the idea boring, I listen to audiobooks while I cook. I am doing something that does not involve mindlessly watching tv,which predisposes to mindlessly eating… I am discovering a lot of time I didn’t have before.And A lot more energy.
    But obesity is not a desease. It’s laziness.Some people have a harder time fighting it-I am sure if my family had been more active, I would have leaned better habits.
    A year ago, I would have written a more politically correct post-we’ll se what I have to say 15 lbs from now.

    • SmartDoc

      Excellent comments.

      I will remember your axiom: “If you’re not hungry enough to eat an apple, you’re not hungry”.

      • gzuckier

        excellent axiom.
        another one (remembered from some stand-up comedian’s act):
        “You’re not supposed to eat all you can eat”.

  • Freda

    I suspect it would be easier to watch our weight if we didn’t have to eat food, but you can’t just give up. Thanks, both yourself and Dr D for some interesting thoughts about why some of us want to eat.

  • Finn

    Classifying obesity as a brain disorder based on this info is a stretch. Classifying food addiction as a brain disorder makes more sense, but we don’t know how much obesity is actually attributable to food addiction and how much is attributable to simply eating too much and moving too little, two things that contemporary culture promotes.

    • gzuckier

      excellent point; obesity can have multiple causes, not just overeating; conversely, people (particularly young people) can overeat and manage to keep a decent BMI, which gives them trouble in later life when their metabolism downshifts.

  • Muddy Waters

    I lost 30 pounds eating 1800 calories per day over 60 days. I did not stratify the calories based on protein, carbohydrate, or fat. Nor did I lift one weight or run one mile. It’s all about personal discipline, which is something our country generally lacks as a whole. We are pleasure-seekers, pure and simple.

    • gzuckier

      yeah, but that’s just semantics. when you come to mental processes, can’t, don’t, and won’t are all synonyms.

  • Astrid

    Even if food addiction were a real brain disease, that wouldn’t make its consequence, ie. obesity, a brain disease.

  • Rob Lindeman

    “The reason for this is that there is mounting evidence that food, or certain types of food, can trigger the same addictive effects in the brain as drugs like heroin and cocaine. There is also substantial evidence that some people lose control over their food consumption and exhibit other behaviors (e.g. tolerance, withdrawal) that may meet diagnostic criteria (see below) for substance dependence.”

    “Mounting evidence”, “Substantial evidence”. What evidence? Please provide citations.

  • jsmith

    A little evolutionary thinking can clarify here. Obesity is the result of a genetic-environment mismatch. Human, like other animals, evolved in a food-scarce environment and have adapted behaviorally to that particular environment. Now we are no longer in such an environment but have not changed our genes. Ergo, obesity. Is this a disease? Who cares? Disease is a word. More important to understand the process.

  • gzuckier

    just ask overeaters, or (usually) yourself; people stuff themselves because it feels good. is this physiologically based, or just an attempt to find gratification in its most primitive form, in a world/society where we are kept chasing gratification that’s just out of reach. see also “filling the hole inside me”, “constant gnawing hunger”, etc.

  • Bobby Fernandez

    No way! To turn a disease of this ubiquity in to a brain issue would be to cast it as an affliction rather than a lifestyle choice. We can acknowledge that it is sustained by a damaged brain in other ways than putting in to the DSM.

  • Jane

    We do not understand a lot of factors behind why one person becomes obese and another, with the same eating and exercise habits, does not. Genetics and environmental factors play roles that science has not yet clarified. If you do not like having obese people in your practice or community, start by treating them as PEOPLE, and making sure there are accessible opportunities to exercise safely, buy fresh foods and get treatment for contributing disorders such as depression and anxiety.

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