Freakonomics in the Times Magazine: The Stomach-Surgery Conundrum

For their Nov. 18, 2007, “Freakonomics” column, Dubner and Levitt revisit a favorite topic: unconventional weight loss. In September 2005, they wrote about Seth Roberts, who shed 40 pounds with a diet he crafted through years of meticulous self-experimentation. This week’s column digs into the risks and benefits of using surgery to combat obesity. This blog post contains additional research materials.

  1. There are two main types of bariatric surgery: gastric bypass, and laparoscopic adjustable gastric banding (Lap-Banding), which is less invasive than a full bypass. This paper, from the journal Archives of Surgery, describes Lap-Banding, and reports it to be both effective and safe.
  2. Bariatric surgery is often the most effective treatment for the morbidly obese, and with a mortality rate of around one percent, it isn’t terribly risky, according to this paper by Bennet Omalu (abstract only without subscription). The highest risk is faced by patients who undergo the procedure at the hands of an inexperienced surgeon. This Washington State study, by David R. Flum and E. Patchen Dellinger, shows a strong correlation between survival rates and surgeon experience (abstract only without subscription).
  3. Bariatric surgery can be costly, ranging from $15,000 to more than $30,000, depending on the procedure. But the surgery tends to pay for itself, according to several studies, including this one from the journal Medical Clinics of North America (abstract only without subscription).
  4. The column features Dr. Marc Bessler, a prolific bariatric surgeon and an innovator in the field. More information about Dr. Bessler is available here.
  5. One of the risks of bariatric surgery, for people who are addicted to eating, is what psychologists call “addiction transfer.” According to this Wall Street Journal article, a significant fraction of bariatric patients pick up other addictive habits afterward, like gambling or smoking, or fall into alcoholism.
  6. But that risk is far outweighed by the benefits of the surgery, which include significant health cost savings over the long term, according to this article in Surgery News.
  7. In the column, Dubner and Levitt discuss commitment devices, which are strategies people use to lock themselves into a particular course of action. Levitt defined it more fully last year in the Freakonomics blog.
  8. Short of surgery, one commitment device might be to leave an anatomically correct blob of fake human fat in your kitchen. To see what a disgusting pet fat glob looks like, click here. Fake fat usually comes by the pound, but, for the calorie-conscious executive, sells an office-ready 1-ounce version.
  9. Annual gym memberships are another purchase on the commitment device shopping list for those trying to lose weight. Except that people overestimate by 70 percent how much they will use them, as Dubner and Levitt wrote in their Jan. 7, 2007 column, “The Gift Card Economy.” The column references Stefano DellaVigna and Ulrike Malmendier‘s paper Paying Not to Go to the Gym.
  10. The popular new weight-loss pill Alli, which partially blocks the body’s absorption of fat, is a commitment device with real consequences: a person who takes Alli and then eats too much may experience a bout of oily diarrhea. (Among the initiated, this is known as an Alli-oops.)
  11. But commitment devices don’t get much more real than the one used by the legendary Chinese general Han Xin. Before battle, Xin was known to arrange his troops with their backs to a river, so they knew retreat wasn’t an option. More on his story here.


What a crock. Weight loss isn't successful if it isn't permanent and maintainable. How do you define permanent? I'd define it to be over the course of a lifetime. But we don't really have any studies for that. How about 5 years out from the diet or surgery? How about 10 years out from the diet or surgery? To the person who commented that 5 to 9 years out you have a chance of dying from lots of other things not related to a "successful" weight loss surgery. That's true, but studies have shown that people who have WLS die much more often than people who didn't have WLS. Even fat people who didn't have WLS don't die as often.

Look at bariatric surgeries 10 years out. Spell out how we are defining success. Is it a 10% loss? More? Less? So if a study defines a successful bariatric surgery as an overall weight loss of 20% of body weight over 5 years, and the patient weighed 300 pounds at the time of surgery what does success look like?

Success looks like a morbidly obese person who now weighs 240, and can also no longer absorb nutrients from a regular, healthy diet.

And I guarantee that if you actually do your homework, and read the studies, checking carefully to determine how they define success, what cases they are excluding from the final results and why, and look at the long term picture, you will find that the surgery is a disaster for a very large portion of the people who do it. Especially note the number of people who are "lost to follow up" in these studies. Do you really think that all of those people are now living in a size six?



Aside from the debate about the merits of bariatric surgery, I do think the idea of a commitment device is an interesting concept in terms of incentives. Weight loss, however, is a particularly difficult realm to discuss it in. On one hand it's personable and something many people can relate to. But on the other, it's a combination of psychological and physiological factors and much more complicated than simply not gambling or not running up a huge credit card bill. One CAN simply throw out the credit cards or stop going to casinos. One cannot stop eating altogether.

Though as another aside, I'm kind of horrified by the blobs of fat as a deterrent. Some degree of fat cells are required simply to live. I believe it's 4-6% of body weight for men and 12-14% for women. Having something in my kitchen meant to elicit feelings of disgust towards a not insignificant part of my physical self? I'm kind of horrified.

But commitment devices for less physiological issues? Very interesting. The best I can come up with was setting a test date for an exam I had to take. Once it went from "within the next few months" to "a week from wednesday, or else" I was much more motivated to study.


A Fat Guy

A question for both Dr. Itzkoff and A Member of Overeaters Anonymous...

Do either of you have any clinical evidence that psychiatric treatment/12-step programs are any more effective than any other form of treatment? I'd like to see it if any exists.


You have a poor understanding of why people become obese (and there isn't just one reason). To simply decry people for "eating too much" doesn't help. Many obese people have displayed extraordinary discline time and again with, only to ultimately succumb and fail.

Prior to having children, I was always thin and disparaged the obese, having seen my grandmother and mother struggle with obesesity. After my first child, I gained a great deal of weight. Fortunately, I had never used food as an emotional comfort and do not have an addictive personality. I have gradually lost some of the weight, but it is a struggle. This experience gave me a real insight into how people become grossly obese.

Yes, some people will have bariatric surgery because they want "the easy way out," but do not think that, at least at present, all bariatric surgery patients blithely opt for surgery.

Be more respectful of deep-seated problems in the future.



To rini:

"Doing it (eating less) is impossible for obese people."

Your statement is simply absurd. As the author pointed out, just 30 years ago there were far fewer obese people. So how come people who had no problem eating less 30 years ago all of a sudden find it "impossible" to eat less now?

You can blame genetics or "the society" all you want. But let's face it - obese people eat more because they *choose* to do so. Other countries have far fewer obese people as a % of their general popukation. Why is it that people in other countries can eat less but doing the same thing is deemed "impossible" by americans?

Let's call a spade a spade - it's a problem of personal responsibility.


Please, get to real...the problem is being fat in this country is akin to being an axe murderer.

People will go to any extreme to lose weight because to be fat is to be constantly vilified.
We have two types of commercials on television in this country food and weightloss.

There is also an attempt(successful)in this coutry to link every medical disorder to obesity. Most of this is not evidenced based research but it allows health care providers,the insurance industry and any company with a stake in the shrinking health care pie with an actual visual cue of the "potential" problem children who may cause a spike in their longterm healthcare costs.

Please note this includes you the pleasingly plump and will eventually touch you, yes, the forgotten underweight. This will morph into which body types tend to be healthier (sorry endo's) and run right into who has a healthy genetic profile.

We have already have a fantastic amount of the ground work completed as it is acceptable to call anyone who is fat any name,ascribe any attribute and openly discriminate with immunity.

I don't think you have to walk around in a fat suit in NYC to see why someone would risk their life to lose weight. Again, we are not talking about a healthy normal now need a body weight that is deemed aceptable to at least 75 percent of the population to be considered
slim ( please make sure your proportions are correct). Do you actually think this is about caring if people are healthy? With money and a handy their personal responsibily logic card safely on the table...



As a certified fatso (365 lbs.) I find that the only thing that controls my appetite is to keep my glucose level low by eating complex carbohydrates like brown rice. My glucose level becomes high whenever I break my diet by pigging out on simple carbohydrates like pastries or pasta. High glucose causes me to crave more food. Eating whole grains helps me break the viscous cycle . Exercise helps too. Yet, it's very easy to “fall out of the saddle” because temptation is everywhere, and old habits die hard.

Paul Bowers

Actually, the obese and overweight don't eat more than the non-obese/overweight; it's myth. Take a look at studies on weight balance and you won't find any that say caloric intake dictates weight gain/lose. Impaired glucose metabolism is almost solely to blame for the diabesity epidemic, and the overwhelming majority of overweight/obese have problems with insulin (the fat-storing hormone). So telling fat people not to eat so much is ridiculous; the problem is not lack of will power or exercise, it's lack of insulin control.

Overly simplistic reasoning applied here!


Alli (or Orlistat) has been used for the treatment of obesity for a long time, and with the experience gained from this time, 2 points can be made: 1: Weight loss will be modest(average 2.9 kg more than placebo with a follow-up of 1-4 yrs (Rucker et al. BMJ 15 Nov 2007, and 2: using orlistat has a lot of adverse events, which will affect compliance negatively.

A recent review demonstrated that the long-term effects of behavioral therapy for obesity are disappointing (Psychother psycomed med psychol 2007 Nov;57(11):420-7)

The focus on bariatric sugery from a medical point-of-view makes sense. two studies published in the new england journal of medicine had demonstrated that bariatric surgery reduces mortality rates significantly (Sjostrom et al. N Engl J Med 357:741, August 23, 2007; Adams et al.N Engl J Med 357:753, August 23, 2007 ( When people present themselves at the outpatient clinic with being overweight or suffering from type 2 diabetes,bariatric surgery (especially bypass) is the best treatment that can be prescribed!

An interesting other theory to explain the óbesity epidemic' is based on a paper in the Annals of inernal medicine. Epidemiologic studes demonstrated that, as the prevalence ofobesity increased, the average amount of sleep (in hours/night) decreased. In the paper, the authors demonstrate that sleep curtailment increases hunger and appetite and alters certain hormone levels in a way that would increase food intake (Spiegel et al. An Int Med. 2004;141:846 ( Although it would be absurd to point to sleep reduction as the sole reason for the 'obesity epidemic', just stating that 'people just eat to much' is too.



Dubner and Levitt first ask why many obese people chose the "drastic" option of bariatric surgery. Well, consider this: for the extremely overweight - heck, even for people with just 10 pounds to lose - losing the weight is only the first, really difficult hurdle to deal with; *keeping it off* is even more difficult. Regain is extremely common, particularly when you demand of the body a loss of 100+ pounds. And so, with each weight-cycling of loss/gain/loss/gain, the body becomes less adept at losing weight and very inclined to cling to it, instead.
Desperation (and hatred - which is both self and other - generated) is why obese people often feel driven to risk their lives through bariatric surgery.
This view of the problem, backed up by science, still seems to let fat people off the hook too much, for many. Could this be why Levitt and Dubner decide, from *their* "vast cerebral storage network" that it's really because surgery is just an easy way out, after all. Yup, it's just like a dumbed-down game-show (an oxymoron, if ever there is one). To quote L & D on the latest trend in game shows: "“Deal or No Deal,” which requires no talent whatsoever beyond the ability to randomly pick a number on a briefcase."
Fat people just want the "easy" way out.
Listen, please: Obesity is almost a crime these days and thinness is the only reprieve. It doesn't really matter how you get "pardoned", either, as People Won't accept health improvements, even if you don't lose much weight. You can exercise and moderate your eating, but only massive weight loss matters when you are obese. It's be thin or die. And so: people get their innards switched around. Some would even say they get them butchered. Desperation to be thin, not stupidity and not the "easy way out" is what drives people who are obese.



Mark in #3: That's a poor example of a commitment device. You can stop payment on the check. Depending on your bank's policies, the "cost" to you may be as little as making a single three-minute phone call.

Paul Bowers

To john,
You say that obese people eat more than their bodies need? But why is it that when I eat more than I "need" (~4000kcal/day), my weight (~75kg) never increases (and in fact has decreased in the last year), but many obese people continue to gain weight on much fewer calories? Is it genetics? Do I have some genetic predisposition to burn more calories than the obese? I don't think so. You see, on a low-fat, high-carb diet, I was gaining weight eating fewer than 2000kcal/day. How does that fit into your first law of thermodynamics? Don't forget, there's a second law of thermodynamics!


To Paul Bowers,

How do you know you need 4000kcal/day? Just because some website you found on the Internet spits out that number doesn't make it a scientific truth.

And why does it surprise you at all that you lose weight on 4k calories a day while others gain weight on fewer calories. So *different* people need *different* amount of calories to maintain their weight - is that really such a shocker? I mean, we're talking about different people here right?

And there's also nothing surprising that you were gaining weight on 2K calories per day. After all, we're talking about different periods of your life here. The amount of calories your body needed could very well have changed. Also, when you changed your diet, the % of calories your body absorbed could also have changed. But just remember, you can never absorbed more calories than you eat. So if you were eating 2000 calories a day, you could never absorb more than that. And if you were gaining weight on that diet, it means your body needed less than 2000 calories a day during that period of your life.

None of the above violates the 1st law of thermodynamics. And yes there is a 2nd law, but your body weight really has nothing to do with entropy...



Some people have brought up Overeater's Anonymous as a possible solution. Although it works for some, there are also many *very* valid criticisms of OA, such as:

"OA has been the target of feminist criticism for encouraging bulimic and binge eating women to accept powerlessness over food. Feminists criticize that the perception of powerlessness adversely affects women's ongoing struggle for empowerment. Similarly, teaching people they are powerless is liable to encourage passivity and prevent binge eaters and bulimics from developing coping skills. These effects would be most devastating for women who have suffered oppression, distress, and self-hatred."

"Opponents of Twelve Step programs argue that members become cult-like in their adherence to the program, which can have a destructive influence, isolating those in the programs. Moreover this kind of fanaticism may lead to perception that other treatment modalities are unnecessary. Surveys of OA members has found that they exercise regularly, attend religious services, engage in individual psychotherapy and are being prescribed antidepressants. This is evidence that participants do not avoid other useful therapeutic interventions outside of Twelve Step programs."

"The concept of abstinence in OA has been
criticized for its inherent ambiguity. While in AA abstinence means not drinking alcohol, there is no direct analogy for compulsive eaters."

There are more problems than space enough here to list them all. OA is not a good solution for many people, but if one critiques it, people in OA freeze you out. Many people in OA can't seem to bear that other people can and do chose other paths that *work for them*, when OA *does not work*.



OK, I'm not even going to justify the stinky-ziploc-under-the-nose remedy with a comment, as I'm sure any statement that stupid could only have the purpose of provoking controversy.

The misconception that overweight people simply lack willpower continues to baffle me. All told, I'm sure I have lost and gained well over 100 pounds throughout my life. I have come to suspect that the gaining required just as much willpower as the losing.

People who are overweight often suffer from self-destructuve behavior, very low self-esteem and a poor body image. They are pretty good at telling themselves that they are utter failures for not being able to lose weight, so really, there's no reason to remind them.

My experience has been that 400 hours of psychological therapy has had only limited success at changing these underlying causes. What I have found to be the best remedy has been the discovery that it's just really fun to have a body, no matter how I feel about how it looks or about the person it contains.

This has occurred incidentally and incrementally since moving to Europe eight years ago. I started out riding my bike most places. Gradually, without really noticing it, I have ended up riding my bike everywhere, no matter what the weather or how far. About twice a year I get on a bus to go to the airport when I fly to the US.

At some point that wasn't enough, especially in the dark Nordic Winter, so recently I joined a gym. Four or five days a week I spend two or three hours working out. I now have more strength, endurance and flexibility than many women who are much younger and slimmer than I am, and I have seen some very attractive bodies in pretty poor shape.

Now I've gotten to the point where I lose weight sometimes, and when I don't, it would take more than even I can eat to gain it back.

Not everyone who is overweight is unhealthy, but those who are pay a terrible price in quality of life and self-image. They feel trapped in their bodies. So maybe the best way to help them is not to remind them of all the things that are wrong with them. They are better at that game than you are. Help them remember what a joy it is just to have a body, no matter how inadequate it might seem to be.

Take them for a walk down the street. Next week you might get them around the block, and next year you might not be able to keep up with them anymore.

PS I think a more interesting column might be about why it is that a smoker who wants to quit smoking and knows that a piece of nicotine gum will quench his desire for a cigarette, decides to light a cigarette instead of putting a piece of gum in his mouth. Or how someone who wants to lose weight and knows that he will buy healthier foods if he is not hungry when he goes to the supermarket, goes to the store on an empty stomach. Somehow it seems to me there must be an economic correlation for the fact that someone who wants a cigarette or a cookie doesn't really want to not want one when he wants one.


A member of overeaters anonymous

Much criticism of OA has been posted here. I'm not going to respond except to say the program has saved my life and I've heard the personal testimonies of many who feel the same.

The program is not for everyone. You do have to be willing to change. The 12-steps will help you do that but you must be willing to use them. For me that willingness only came after trying everything short of bariatric surgery.

For those who are wondering if it might work for them, I encourage you to check into it (no fees or commitments). What have you to lose except a lifetime of struggle? And I have received so many benefits in addition to maintained weight loss. I'm including the OA website link.

For those of you who are sure it will not work for you, best wishes in the path you choose. If you change your mind, you are always welcome to OA.