The Obesity Paradox

Being fat is bad except when it’s good. It’s called “the obesity paradox.” (No, that isn’t a mis-spelling for “two physicians who treat fat people.”) The adverse health effects of obesity are well established, but there are exceptions. Obesity appears to confer an advantage in certain subgroups with conditions like heart disease and diabetes.

In the News

Casual consumers of some recent media reports might interpret them as an excuse to stop trying to lose excess weight, especially if they are diabetic. Others might think we have been lied to about the dangers of the obesity epidemic. The reality is more complicated.

An article in the NY Times asks:

Obesity is the primary risk factor for Type 2 diabetes, yet sizable numbers of normal-weight people also develop the disease. Why?

The question is a bit misguided and the answer is simple. Obesity is the primary risk factor but that doesn’t mean it is the only risk factor or the cause of the disease, and non-obese patients who develop diabetes obviously have other risk factors. We know Type 2 diabetes is a multifactorial disease involving interactions between genetic, environmental, and lifestyle factors.

The article highlights recent research showing that:

Diabetes patients of normal weight are twice as likely to die as those who are overweight or obese.

And not just in diabetes:

In study after study, overweight and moderately obese patients with certain chronic diseases often live longer and fare better than normal-weight patients with the same ailments.

That’s true. Overweight and obese patients undergoing dialysis have better outcomes. Overweight people have better outcomes from heart failure and peripheral artery disease. After cardiac revascularization surgery, obese patients have similar or lower mortality rates compared to non-obese patients.

A simple interpretation of these findings might be that obesity must not really cause diabetes, that being obese is healthier than being non-obese, and that the concern about an “obesity epidemic” is misplaced. As usual, simple is wrong; reality is more complex.

Obesity and Diabetes

If you are overweight, the most effective thing you can do to prevent diabetes is to lose weight. The Diabetes Prevention Program study of patients with prediabetes showed that weight loss was the primary predictor of risk for developing the disease. Weight loss and exercise lowered the risk by 58%. Losing 5-10% of body weight significantly reduces blood sugars and allows many type 2 diabetic patients to get off their insulin and medications. The ADA recommends weight loss both to improve diabetic control and to reduce the risk of complications.

If you already have diabetes, there is evidence that losing weight is beneficial. In the Cancer Prevention study, patients with diabetes who lost weight had a 25% reduction in total mortality and a 28% reduction in cardiovascular plus diabetes mortality. And the benefit persisted even if they regained weight. But patients who lost more than 70 pounds had small increases in mortality.

In the National Health Interview Survey, patients who were trying to lose weight had a 23% lower mortality rate than those who were not trying to lose weight, even if they didn’t lose weight! Actual weight loss was associated with increased mortality only if the weight loss was unintentional.

A JAMA study suggested that people who are normal weight at the time of diabetes diagnosis may not be comparable to overweight diabetics. They may be at a disadvantage due to other factors like their ratio of muscle to fat (“thin outside, fat inside,” or TOFI).  It may be a matter of fitness, not fatness.

Obesity and Cardiovascular Risk

A systematic review of 40 studies in The Lancet looked at the relative risk of total and cardiovascular mortality compared to a baseline of 1.0 for people with a “normal” BMI of 20-25. Their data show that the death rate is lower for people who are mildly to moderately overweight, but it is greater for those who are underweight or very overweight.

BMI RR for Total Mortality RR for CV Mortality
<20 1.37 1.45
25-29.9 0.87 0.88
30-35 0.93 0.97
>35 1.1 1.8

Several hypotheses have been proposed to explain these findings. For instance, one study suggested that obese patients have an advantage because they are treated more aggressively.  The increased risk in the underweight category is not surprising: some of those underweight people are malnourished, cachectic from cancer, or are in poor health for other reasons.

Morbidity: Death Isn’t the Only Consideration

If obesity doesn’t kill you it could still hurt you in lots of other ways and make your life less pleasant. In addition to the obvious practical, social, and aesthetic disadvantages, there are a number of serious health consequences short of death. The Wikipedia article on obesity-associated morbidity  provides a handy list of all the health problems associated with obesity. It’s a long list, divided into 10 categories from cardiology to urology. It includes gallstones, infertility, congenital defects, gastroesophageal reflux disease, stroke, carpal tunnel syndrome, multiple sclerosis, obstructive sleep apnea, erectile dysfunction, and many others.


There really is no obesity “paradox” — there is just a complicated situation. Obesity predisposes to developing a number of health problems. Once those problems have developed, in some cases patients who are overweight have a survival advantage over patients who are not. That advantage diminishes as weight increases and eventually turns into a disadvantage when the weight gets high enough. Being underweight is also a health risk. Fitness may be as important as fatness. We don’t yet understand what all this means: we have hypotheses, but so far they are not supported by credible studies.

The Bottom Line

Obesity is a health hazard but it should not be over-simplified or categorically demonized. It is a complex issue with exceptions to the general rule. Science supports trying to control weight in general but it doesn’t support forcing every individual into the same mold of an ideal BMI range of 20-25.



Posted in: Nutrition

Leave a Comment (85) ↓

85 thoughts on “The Obesity Paradox

  1. gippgig says:

    One plausible explanation is that being heavyset is beneficial (since BMI tends to classify heavyset people as overweight). Has this been tested?

  2. Harriet Hall says:


    That’s where the “fat but fit” comes in. BMI is only a heuristic proxy for body fat, and is misleading in heavily muscled people.

  3. pytra says:

    I just wonder about the multiple sclerosis/obesity association. Is is correlation or causation? As a MS patient who is overweight, I feel that this assocuation is fallacious : as MS cannot be “reduced” or “cured” by weight loss, I wonder if weight gain might “create” MS.

  4. I like the thesis of this post: that while X may be a risk factor for Y, X isn’t the only cause of Y.

    We see this a lot, for instance, LDLs and heart disease. And diabetes and heart disease. Etc. Most diseases have multiple independent risk factors. This seems to be the gambit science deniers use: “His LDLs were 71, but he had a heart attack, therefore LDLs are not associated with heart disease.” (In a 260 lb diabetic!)

  5. pytra says:

    meh. I’ve just read the study, and it clears things out.

  6. windriven says:

    Dr. Hall, could you please check the link to the Lancet study? I’m getting an “article not found” error.

  7. Cornelioid says:


    I think i’ve found it. Until Dr. Hall returns, here is the abstract in Pubmed, and here is the full article at ScienceDirect. (Sorry if it requires some kind of access; i’m on campus so i don’t know.)

  8. evilrobotxoxo says:

    There are (at least) two major confounds here.

    1) people who have obesity-related disease when they’re not obese probably have a more severe form of the disease.

    2) lots of chronic disease states cause weight loss, and many “normal weight” people are obese people who lost weight from being sick, not people who are at a normal weight because of healthy diet and exercise.

    Fundamentally, there’s a paradox only if you confuse correlation with causation. Obesity might be correlated with better outcomes on the population level, but each individual obese patient is still better off taking steps to lose weight.

  9. windriven says:


    Many thanks. That link works.

  10. WilliamLawrenceUtridge says:

    My BMI is around 28 but my doctor doesn’t bother calculating it ’cause it’s quite obvious that it’s not coming from pizza and beer. I’d be interested to see how the results change if they used a waist-to-hip ratio or similar calculation.

  11. pytra says:

    @evilrobot : that works only if diets work. and… oh, they don’t.

  12. nord says:

    BMI is not very good at predicting an individual’s fatness (not what it is intended for- physicians really should learn to do BF%) but is pretty solid when applied to large populations. So, William, you may find it very inaccurate for yourself. The measure that could be better is body fat percent, however this has problems too. The fastest and easiest way to do this in a study would be with skin-fold calipers. However, the error is higher on obese patients so it is not a good tool for studying thin vs obese. DEXA is probably best but way more expensive than just calculating someone’s BMI. You may find some studies that actually use DEXA. I’m guessing BMI was the only measure that was in every study of the review and it is probably appropriate for a large n here.

    I saw a review once showing overweight, but active, individuals at less risk of mortality than sedentary, normal weight. I think the current study would be very interesting if it looked at subjects’ fitness level as well. It at least is a possible confounder here (i have not read the review yet- maybe they discuss that)

  13. Calli Arcale says:

    nord: one group that might be interesting to study is obese athletes. They do exist; in particular, certain football players (who are encouraged to add mass so as to function more effectively as a wall) and of course sumo wrestlers (who put on mass for much the same reason). They train heavily, so their hearts are probably in better shape than someone of the same BMI or even fat ratio who got that way by sitting on the couch and eating pork rinds. Compare linebackers to their fans, IOW. ;-)

    I’m one of those people who is more heavily built than the BMI seems to expect. I’d still be healthier if I was within the normal BMI range (I’m a smidgeon into the overweight category, based on BMI), but I probably don’t need to get all the way down to the 122 that BMI calculators recommend for me. When I was at my fittest, I weighed closer to 130, but I’m broad-shouldered and short-legged — I’ve probably got as much bone mass as a taller woman. I’m also naturally muscular for a woman who doesn’t work out a lot, which adds to it. My youngest daughter seems to be following in that trend, although it seems that she might end up with even broader shoulders, and more muscle — this is a kid who held her head up within an hour of birth. Tough little cookie. ;-)

  14. evilrobotxoxo says:

    @pytra: bariatric surgery works.

  15. rork says:

    evilrobotxoxo’s point 1 is what I was going to make:
    The less overweight people with diabetes may have some really nasty genes. They aren’t like the others on average.

    That’s common in cancer. For adrenal or certain ovarian cancer patients, being mutant at APC (or Beta-catenin, etc) is “good” compared to other people with a similar tumor, simply cause those other people have an even more wicked mutation in their tumor (like TP53). But having germ-line APC mutation is a death sentence. A colon cancer may kill you before (or after) you get the ovarian cancer.

  16. Teliria says:

    I think the portion that talks about ‘trying to loose weight’ is protective even if there is no weight loss, is important. I am overweight. For the past two years, I have changed my diet to exclude the obvious ‘bad’ stuff (fast food, etc) and have focused on eating healthier foods. I have also focused on at least 30 minutes of physical activity per day. I have only lost 5 pounds, but all of my health markers are in ‘healthy’ range. My doctor is perfectly happy with everything (cholesterol ratios, blood sugar, bp, etc). Of course, he would still like me to loose weight… heh.

    I really wish people would focus more on ‘living healthy lifestyle’ rather than weight. If someone with diabetes is cheating on diet to the degree that contributes to them dying of diabetes related conditions, they most likely are going to be carrying extra weight. That overweight person is going to be counted in the ‘overweight’ mortality count…. the person who is ‘trying’ to loose weight is going to be eating a healthier diet…. basically, I can not help but feel that it is the ‘what someone is eating’ that is either protective or not, rather than what their weight is.

  17. Janet says:


    Depends what you mean by “diet”.

    Faddish eating plans that come and go do not work–not long term anyway.

    Eating sensibly and within the actual caloric needs of your body does work. People, even skeptics, want magic. Losing weight is simple, but certainly not easy, and that’s the big variable between failure and success. You can learn to eat less, but you will have to make changes and give some things up, unlike what most of the “diets” try to tell you.

    By the way, for those who don’t already know this, I lost 45 lbs (I’m 5’ 2”), six years ago, by cutting my daily calories by nearly half–and sticking with it. My longstanding pre-diabetes which had recently crossed the line, disappeared after the first 20 lbs, and my lipids normalized. My BP almost normalized, but I still use meds in much reduced dosage. My BMI is now normal, even though I am an “apple” shape. I used to run, but now settle for walking, and some pretty heavy duty gardening on my little “urban farm”.

    I know this is an anecdote, but I think it is illustrative of the value of controlling weight in most cases. There is rampant early onset heart disease in my family but little diabetes–many didn’t live long enough to develop it!

  18. Finn says:

    Similarly, BRCA mutations vastly increase a woman’s risk of ovarian cancer, but ovarian cancer patients with BRCA mutations tend to survive longer than ovarian cancer patients without such mutations.

  19. mousethatroared says:

    Is it just me or is the study on the correlation between overweight teens and higher rates of MS a little funny. I think they suggest that preventing obesity in teens may lower the risk of MS, but I am not seeing how they showed causation.

    Just curious I guess. Not that important.

  20. Harriet Hall says:


    That study showed a correlation but it did not show causation. I don’t think it’s been replicated, and it was based on self-reports, so I would consider it no more than a preliminary suggestion.

  21. Teliria says:

    Clarification: I feel very strongly that ‘diet’ should NOT ever be used as a verb. Ones ‘diet’ is what one eats. We can have a healthy diet or an unhealthy diet. I aim for a healthy diet every day and actually achieve that about 6 out of 7 days. I have never seen someone who ‘diets’ (V) who is able to maintain a healthy ‘diet’ over any realistic amount of time.

  22. evilrobotxoxo says:

    I think one important thing many people overlook is that body weight, or even body fat percentage, are very crude variables that lump a lot of underlying causes together. People might have a high BMI because they’re muscular, obese, or constitutionally heavy-set. People who are obese might be that way because of overeating, medication side effects, depression, drinking too much, etc. People who overeat might eat a little too much all the time, might binge compulsively, might engage in “emotional eating,” etc. Lumping all these variables together under a single variable of weight (or BMI, which is just weight normalized by height) simply isn’t helpful. Similarly, trying to lose weight should be guided by knowledge of why the person is overweight to begin with; some causes are easier to treat than others.

  23. mousethatroared says:

    Thanks, HH!

  24. ConspicuousCarl says:

    I don’t know how much weight in muscle someone would gain from standard exercise, but I was wondering if some of those “trying to lose weight people are gaining muscle and losing fat, making them healthier without a net loss.

  25. gippgig says:

    Heavyset does not mean muscular. Heavyset means thicker everything – thicker bones, thicker muscles, thicker fat, etc. You can be heavyset and lightly muscled just as you can be thin and muscular.

  26. Harriet Hall says:


    Sounds plausible, but I don’t think heavyset is a medical definition, and I don’t know how you’d define and measure it to study its effect.

  27. icewings27 says:

    @gippgig – I see what you are getting at. Perhaps the medical profession needs a term for “people whose BMI is inaccurate due to a naturally heavier build.” Something like “stocky” or “sturdy”, which is how I like to describe my bigger-than-average-but-not-fat self.

  28. Solandra says:

    I started exercising and eating healthier about three years ago and lost 60lbs. I still need to lose probably another 60 according to my doctor, though all my markers are great, I’m vegan and athletic.. I ride my bike to work and exercise a lot and eat mostly plants. My hypothyroidism makes it exceedingly difficult to get “skinny”, and I am a naturally muscular woman anyway. I think we should put the focus on the behaviors and not being “thin”, and doctors need to stop being such dicks about people fitting into a certain weight category.

  29. fledarmus1 says:

    So what we really need is a good full-body CAT scan from which we can digitally obtain bone density and volume, combined with a good full-body 3-D MRI from which we can calculate body volume and tissue densities, and a good algorithm that will combine the two to give a measure of deviation from a calculated ideal distribution of fat and lean mass. Assuming bone mass and density stays relatively constant, you could simply follow periodic MRIs to determine whether your body was moving towards or drifting away from its ideal composition. That shouldn’t take a good medical research group more than a couple of years to develop. Probably cheaper than a moon-shot against cancer. How much would a good tissue distribution index be worth?

  30. evilrobotxoxo says:


    Something like that would be too expensive. What we need is to standardize and validate simpler measures that can be done in a clinic or at home, such as chest to waist ratio, skin caliper tests, etc., and use those to replace weight/BMI.

  31. RD says:

    Kind of crunched for time right now, but I wanted to throw this in the loop about MS/obesity. Could it be more related to vitamin D levels? Since people that are obese are at higher risk of vitamin D deficiency (or at least need more vitamin D) and vitamin D status is being looked at regarding MS?

  32. jmb58 says:


    If I had a dollar for every overweight person that told me how good they eat and how much they excercise I wouldn’t have to be such a “dick” because I could retire. 60 pounds from your ideal body weight, and your doctor is a “dick” for suggesting you lose more? Instead of blamming your thyroid and bragging about eating vegan try riding that bike a little further.

    A common scenario:

    Me: “Ma’am, you need to lose 40-50 pounds before I fix your hernia or you are at high risk for recurrence, infection, and a blood clot.”

    Patient: “But I eat organic and do Zumba. I’m very healthy.”

    Fastforward 2 months to the “dick” doctor elbow deep in adipose tissue.

    Fastforward 1 more week.

    Patient: “Why did I get this wound infection?”

    Me: “Uhh…sorry”


    You are joking, right?

  33. @fledarmus1,

    Wow. So you think we should expose someone to full body radiation to calculate BMI? And then follow them up with multiple-thousand dollar studies to look at fat vs. muscle? This is honestly one of the most dumb things I’ve read. Ever.


    So, you are 60 pounds over weight, which would likely classify you as severely or morbidly obese, which puts you at high risk for many diseases, and yet you call your doctor a “dick” for recommending that you lose weight? Newsflash. You need to lose weight. And no, you can’t blame it all on your thyroid. I know you just wrote that you ride your bike and eat plants, but I’m sure if we delved deeper, we’d find the source of your extra weight.

  34. ^ closing up the body after surgery is much more difficult for people with a lot of body fat.

    Otherwise, I won’t repeat the rant I have had in SBM comments before on fitnesss rather than weight, since a host of other commenters has made the point for me.

    A valuable idea is to consider that the vital sign of BMI is the wrong vital sign; what is needed is a sign that captures aerobic fitness.

    A standard 400 meter corridor walk, “long-distance corridor walk,” LDCW, might be a leading prospect. Simonsick, Montgomery, Newman, Bauer, and Harris, 2001, J Am Geriatric Society v 49.

    You instruct a person to cover 400 meters, 10 times down and back along a marked course 20 meters long in a clinic or hospital corridor, “as quickly as possible, at a pace you can maintain.”

    The authors note this takes 5 min on average.

    There are many outcome measures, and work would be needed to see which is the leading fitness indicator. but you can measure BP pre and post, you can measure heart rate pre, during, and post, and you can measure respirations per minute (better than the usual 15-sec-X-4 = minute-rate shortcut).

    There are other great measures of fitness, but they are more difficult to carry out for various reasons including apparatus needed and skills needed to administer. VO2 max, HRV, red blood cell density are not as easy as the LDCW.

    Possibly, there might be a good test using one of those step-aerobics steps, and asking someone to do that at some rate in some time frame, and assess same stuff as LDCW.

    Any other thoughts on a measure of aerobic fitness as a standard vital sign? How can a doc know how fit any given pt is? What would be better in longitudinal studies of mortality?

  35. jmb58 says:

    There are 3 reasons, to my mind, that BMI is used in medical settings. Bear in mind I’m a surgeon so I think more acutely than a primary care doc might.

    First, it is easy to calculate. You have to measure height and weight anyways. Having someone walk a 40 meter course 10 times is incredible labor intensive and time consuming.

    Second, most of the time I only need an estimate. I don’t care if a patient has a BMI of 22 or 28. But a BMI of 35 or 50 is significant. And it’s easy to tell the patients that have so much muscle mass that the BMI calculation isn’t meaningful.

    Third, it is the measure used in the literature. Nearly all of the surgical studies looking at outcomes related to obesity use BMI. So an individual’s BMI helps give some perspective of their risk profile.

    Heart rate and blood pressure aren’t perfect measures either. A heart rate of 90 means different things to different patients. You look at all the data to get a clinical picture. BMI is one piece of data that is considered and analysed as part of that clinical picture.

    “How can a doc know how fit a pt is?”

    I ask them. Can you walk down the street without chest pain or shortness of breath? Can you climb a flight of stairs? If you can climb a flight of stairs without symptoms, you can probably tolerate most major surgeries, even lung resections.

    If you know and/or care about your VO2 max you are probably an athelete.

  36. dbe says:

    Is there any consistency with how we define “obese”? And is this definition based on anything worthwhile? I mean, if it’s a certain BMI for example, is there any reason we should pick THIS BMI as the checkpoint?

    Furthermore, it would be helpful to see research that studies either the effects of obesity, or how obesity matters in other disorders, split into a range. So if obese = x and normal = y, it would be helpful if some middle level of fat-ness was between x and y.

  37. Solandra says:

    “If I had a dollar for every overweight person that told me how good they eat and how much they excercise I wouldn’t have to be such a “dick” because I could retire. 60 pounds from your ideal body weight, and your doctor is a “dick” for suggesting you lose more? Instead of blamming your thyroid and bragging about eating vegan try riding that bike a little further.”

    Glad you aren’t my doctor I guess. The point is, even when I eat about 1,200 calories day and ride my bike 20 miles, I don’t lose weight. I know there are a lot of fat people who insist they are doing everything they can, but I know how to lose weight, I’ve done it before, I’m just at a weight that is considered high for my height. I don’t look bad, though, and all my markers are good.. What I’m saying is, why should I stress about losing the weight that would, honestly, makes me look like a skeletal freak if I did? I don’t want to weigh 115lbs at 5’5″, but my doctor told me I should, according to the BMI scale. It doesn’t take into account my bone structure or muscle mass.

  38. mousethatroared says:

    Solandra – by the NIH BMI calculator a body weight of 149 for a woman 5’5″ would be considered a “normal
    weight” of 24.9 BMI

    Not sure if you have some other health concerns that are causing your doctor to suggest a lower weight, but at 5’6″ woman, I’ve never had a doctor suggest I get down to 18 or 19 BMI.

  39. @Solandra,

    Let’s say you burn 30 calories per mile. If you rode your bike 20 miles per day, that’s 600 calories burned, and if you’re eating 1200 calories per day, and your body burns, at a minimum 1600 calories per day, then you are losing 1,000 calories per day. There’s no way you are living like this and not losing weight (and there’s no way you’re maintaining weight.) Your net calorie consumption is less than movie stars use to drop 30-40 pounds for a role, ie, Christian Bale in the Mechanic, where he turned into a skeleton.

    I’m not calling you fat or anything, I don’t know how much you weight, but your claims for eating and exercise related to exercise aren’t compatible with known science.

  40. Solandra says:

    I’ve tracked my calories and calories burned with SparkPeople consistently and not lost weight. I wish it were as simple as calories in/calories out.. I remember reading something about how the more weight you lose, the less you burn. There might be something to that. Because my body does NOT just burn 1,600 calories a day, I know that much, because if I eat 1,600 calories a day, I GAIN WEIGHT. I have to be very precise just to maintain. It’s extremely annoying. I know it sounds unbelievable, but I can’t help but wonder if there’s something going on with people who have lost a lot of weight and how their metabolisms are affected. And aside from that, I guess, why should we be concerned about a little extra padding if the bloodwork is fine, and you can participate in races and other activities that are extremely athletic? Seems like that is more about conforming to a specific body type due to aesthetic reasons rather than health reasons.

  41. You’re definitely right about one thing, that it sounds unbelievable. You’re 60 pounds over weight, eat 1200 calories a day, and burn at least 600 with exercise, but can’t lose weight? Yeah, I don’t believe it. Doesn’t mean it’s not happening, I just don’t believe it.

  42. Solandra says:

    I would be glad to be a guinea pig. Study me. My surgeon and Endocrinologist have both told me I should be. I think it might upset what people think they know about human metabolism, though.

  43. jmb58 says:

    HH said it best

    “Science supports trying to control weight in general but it doesn’t support forcing every individual into the same mold of an ideal BMI range of 20-25.”


    As a fellow cyclist my only suggestion is to ride your bike more. If it doesn’t work then, hey, at least you got to spend more time on the bike.

  44. Solandra says:

    Well, I just focus on being healthy, eating well, and exercising lots. That’s all I’m saying.. As long as everything is good, if you can’t fit into the mold, then don’t get all angsty about it. :) I’m doing 40 miles tomorrow on the bike.. and that’s before I go work my horses. Weekends are so busy I typically am lucky if I can get down a protein shake, so that’s another thing. My friends tell me I don’t eat enough and that’s why the weight doesn’t come off. Also doesn’t make any sense. I guess I will just have to come to terms with the fact that my body doesn’t make sense, and some people are going to be assholes about it and accuse me of lying.

  45. evilrobotxoxo says:

    @MedsVsTherapy: MDs do ask pts about exercise tolerance, but mostly when they’re trying to monitor the severity of a specific condition that decreases their exercise tolerance. I agree that we need something better than BMI, but the problem with the measure you’re proposing is that it will only work in people who are otherwise healthy. If a person has any sort of underlying heart or lung disease, then exercise tolerance is measuring something else entirely.

    @Solandra/SkepticalHealth: there is literature showing that when mammals are obese for a long time, then their hypothalamic set point is reset so that their brain puts them into starvation mode when they try to maintain a healthy weight. They burn a tiny number of calories, even if they’re exercising heavily, and anything they eat goes straight to fat. It doesn’t mean that the laws of thermodynamics and calories in/out don’t apply, but it becomes very difficult, probably impossible, for people to voluntarily maintain a weight far below their set point for a sustained period of time. The circuitry regulating food intake is becoming better and better understood in recent years, largely due to studies in mice using genetically encoded neuromodulation methods like optogenetics to tease apart the circuitry in the hypothalamus. The problem with translating this to humans is that there aren’t any good drug targets that have been shown to work yet, and standard neurosurgical approaches such as lesioning or deep brain stimulation are unlikely to work because there are so many functionally distinct (and even opposing) neuronal populations packed into a tiny anatomic region. It’s possible that a drug might be found that modulates these circuits directly and is safe to administer in pill form, but I think it’s more likely that future obesity treatments will involve either focal infusion of drugs into the hypothalamus through a surgically-implanted catheter or neurosurgical delivery of viral vectors that are capable of targeting specific neuronal subpopulations at the injection site.

  46. And yet, a sleeve gastrectomy can help a person lose about half of their excess weight in a fraction of the time. I’d contend that no human could maintain theri current weight if they consumed 1200 calories per day and exercised enough to burn 600.

  47. Solandra says:

    @ SkepticalHealth – Ever notice that such a high percentage of people who lose the weight with bariatric surgeries.. gain it all back? And more? Weight loss, no matter how it is achieved, affects your metabolism. Some people just more than others, especially those, like me, who have diseases that also effect their metabolism. There is actually a lot that we don’t understand about weight loss, that’s why they’re continually doing studies. I would love to get in on one and this has inspired me to see if OHSU is doing any.

  48. Alia says:

    Dr Hall, I just want to thank you for the article – just today I’ve encountered a short article on the “obesity paradox” on one of our health portals, based on the same studies New York Times article that you quoted. And having read your text before, I was able to deconstruct the article and I wasn’t very impressed with it (starting with the title “fat saves your health”)

  49. Yes, and I’m sure we can all guess as to why someone who got so fat in the first place that their only option was surgery will eventually regain that weight. But the fact that the sleeve gastrectomy helps them lose weight – hundreds of pounds – throws your entire argument out the window. They eat less… and lose weight! If it wasn’t a function of food consumption, then why does the surgery work?

  50. evilrobotxoxo says:

    @SkepticalHealth: I agree that surgical approaches are really the only evidence-based treatments enabling long-term loss of clinically-significant amounts of body weight, but I don’t think that will be true forever. There are also a number of patients who gain back the weight after lap banding or gastric bypass, there are the risks associated with the surgery itself, and there is the large subset of patients who are too obese to have bariatric surgery. It’s the best we have, but it’s far from perfect. Ultimately, I think that obesity will start to be seen as a public health problem, and our society will focus more on prevention. Patients who have already become obese will be treated though methods that are less invasive than abdominal surgery, probably with meds or possibly neurosurgical procedures.

    @Solandra: I believe you when you say that your resting metabolism has become extremely low, such that your caloric intake vs. expenditures defies common models of calories vs. weight. I’m sure it appears to defy the laws of physics as well. However, there are updated weight loss models that take metabolic shifts into account. I just read an article about it a few weeks ago, and I’m sure you could find info on it by googling. One thing I’d like to point out is that people are extremely bad at estimating the number of calories in food items, and studies have shown that people who are overweight in particular systematically underestimate the calorie content of food. Unless you eat everything out of a package all the time, how do you know you’re eating 1200 calories per day? How does anyone know? Ultimately, we don’t.

  51. BillyJoe says:


    “Yes, and I’m sure we can all guess as to why someone who got so fat in the first place that their only option was surgery will eventually regain that weight. But the fact that the sleeve gastrectomy helps them lose weight – hundreds of pounds – throws your entire argument out the window. They eat less… and lose weight! If it wasn’t a function of food consumption, then why does the surgery work?”

    Because surgery forces them to eat less.

    Despite their best efforts, these patients have been unable to lose weight by eating less. So they opt for the drastic measure of gastric banding which forces them to eat less. Even then there are patients who still cannot stop eating. The lower oesophagus becomes dilated and filled with food which they sometimes regurgitate and aspirate into their lungs.

  52. @BJ,

    Thank you for that fascinating answer, where you beautifully described that because people eat less, they lose weight. Please at least read the thread before you pipe in. What you wrote is actually in complete agreement with what I’ve been saying. The argument that you butted into was from Solandra claiming that despite eating almost nothing, and working out, she didn’t lose weight. I countered that the surgery makes you not eat, and people lose weight (which contradicts what she said.)

    BJ, I have another difficult question for you. When I drop my pencil, why does it fall? And what is the big bright circle in the sky?

  53. David Gorski says:


    The other editors and I have noted that your responses have been not only less than respectful, but at times downright obnoxious and insulting, even to commenters who are not trolls or even particularly obnoxious themselves. While in general we allow wide latitude and rarely moderate anyone and even more rarely ever ban anyon, even though discussions can sometimes get heated That being said, this is not, for example, my other blog, where almost anything goes. In other words, tone it down.

    This has been building for some time, and the only reason I haven’t piped up before is because I’ve been really busy.

  54. BillyJoe says:


    You asked a question, and I answered it. Apparently, my answer is correct. But, despite that, I am still wrong! Go figure. But I guess you were just upset that, in the process of answering your question correctly, I destroyed your argument on the other thread about patients being to responsible for their lifestyle diseases.

    Oh well…

  55. BillyJoe says:

    Oh and…
    1) Curved space
    2) A fusion factory

  56. @BJ,

    I guess the point was your lack o reading comprehension in that you were answering a rhetorical question that I had already answered.


    That fine. There’s about six regular commenters. One is a lying med student with a criminal record, one is a moron from Australia, one is a ruminating stalker, one is an a-hole internist, one is a sterile grandma and the other is a liberal douche with glasses. I could care less.

  57. Harriet Hall says:


    Your last comment is completely unacceptable. And so is your comment about Mouse’s mental health on another thread. Dr. Gorski has already asked you to tone it down. Forceful statements of opinion are one thing, but you have crossed the line. Your vicious spewing of insults will not be tolerated. If you persist, you will be banned.

  58. David Gorski says:


    Harriet’s right. Final warning, Knock it off.

  59. Solandra says:

    @SH: People who undergo bariatric surgery often eat around 600 calories a day for a while. Sometimes less. They also lose their hair and have other symptoms of malnourishment. I guess that’s worth it in the pursuit of looking thin? It is seriously DRASTIC, and I can’t eat 600 calories a day or less because I refuse to literally starve myself in order to be thin. Because I don’t want an eating disorder. You are obviously not interested in the different metabolic issues that can go into reasons why someone couldn’t lose weight, you’re just interesting in insulting others and being a dick, so, I’ll end on that note.

  60. @Solandra,

    Please do not insult me or call me “a dick.” That kind of language is not tolerated here and has nothing to do with the discussion.

    My point stands: it is virtually impossible for someone to eat 1200 calories per day, burn at least 600 in exercise, and not lose weight (especially considering the whole thing about the body continuing to have increased caloric expenditure post exercise.) The body can not sustain itself on 600 net calories per day. As was stated previously by another poster, likely you are underestimating your caloric intake, and probably overestimating your calorie expenditure. If you were severely hypothyroid or depressed, or if you had decompensated heart failure, or on medications that cause weight gain, I could believe the inability to lose weight. Outside of that, I think it’s more likely than not that the error is in your calculations than that it is the laws of physics are breaking down inside of your tummy.

  61. Solandra says:

    ” If you were severely hypothyroid or depressed, or if you had decompensated heart failure, or on medications that cause weight gain, I could believe the inability to lose weight. ” Did you not catch the part where I have Hashimoto’s and half a thyroid and am not properly medicated? Last I checked, my TSH is near 20 and meds are slow to bring it down. I just had surgery for a thyroid tumor in April, so it takes a while, and it took several different doctors to finally diagnose it. HMMM I WONDER IF THAT COULD HAVE SOMETHING TO DO WITH IT. God. Duh. OH but I’m sure you’ll find some other way to call me a liar.

  62. Please converse in a respectable manner. I do not respond to sarcasm or insults.

  63. jmb58 says:

    A couple minor points on bariatric surgery. Which, by the way, I have mixed feelings about. I take care of plenty of the complications. I do not do bariatric surgery.

    “Ever notice that such a high percentage of people who lose the weight with bariatric surgeries.. gain it all back?”

    Guess it depends on what you mean by a high percentage. At one year more than 90% have lost a significant amout of excess wieght (usually more than 50% of excess weight). By five years the numbers who have kept it of is down to 60-70%. By far more effective than any diet ever studied. These numbers are of the top of my head but come from years of reading way to many bariatric surgey studies.

    If the patients do a good job with the suggested after surgery diet and vitamen regimen they maintain good nutrition.

    “there is the large subset of patients who are too obese to have bariatric surgery”

    There aren’t many who have a BMI to high for bariactic surgery. I’ve only seen a handful in my career.


    I agree that someday we are going to look back at bariatric surgery as primative and invasive. Unfortunately I think that day is a long way off. I hope society recognizes the health epidemic that is obesity and there is more emphasis on prevention. Sometimes I feel like progress is being made, and then I see and ad for The Baconator.


    Most of the time I enjoy what you bring to the discusion (I’ve been reading for a long time). So as a fan I’m saying “tone it down so you don’t get banned.”

  64. @jmb,

    Thank you for bringing the actual data to the table. Those are pretty dang impressive numbers for the surgery. Just out of curiosity, how fat is too fat?

  65. jmb58 says:

    I think it depends on the surgeon and the center. There are places specializing in super morbid obesity. I’m not sure but my somewhat educated guess is a BMI of 80.

    One clarification, the lap band procedure has less consistent data. One of the hot topics in bariatrics right now is whether or not banding should still be done. It’s rarely done in Europe anymore.

  66. mousethatroared says:

    Solandra “Last I checked, my TSH is near 20 and meds are slow to bring it down. I just had surgery for a thyroid tumor in April, so it takes a while, and it took several different doctors to finally diagnose it.”

    Solandra – That sucks! I have Hashi’s too, I can say my number’s have never been that bad, but I still felt really rotten, when my numbers were off and it became easier (or should I say, less difficult) to lose weight after my number’s got more into an optimal range.

    A friend of mine had thyroid surgery (twice) and radioiodine therapy. It did seem it took quite a bit longer for her levels to normalize than mine. But they did, so try to hang in there! And just think all that muscle you are building with your riding will work even more in your favor once your levels are better.

    If you don’t mind a bit of unasked for advice. It sounds like you’re not happy with your doctor. From your comments it sounds like you might have good reason to be unhappy. Once you have Hashimoto’s you become slightly more at risk for a bunch of other health issues, bursitis, fertility issues, etc. If possible, it’s worth some effort to find a good (science based ;)) primary care provider that you can build a comfortable working relationship with. It might be a pain, but it will probably be worth it in the long run.

    Hope you start feeling better soon!

  67. BillyJoe says:


    Unless I misunderstood you, I think you’ve confused your thyroid disorders.
    Hypothyroidism is treated with thyroid hormone replacement, never surgery or radioactive iodine. Along with anti-thyroid drugs, those are treatments for hyperthyroidism.

  68. mousethatroared says:

    BillyJoe – Thyroid cancer is treated with surgery and radioiodine therapy. Once someone’s thyroid is removed they ultimately become hypothyroid and need thyroid replacement. Where is the confusion?

  69. @BJ,

    You misunderstood because you do not have knowledge about surgical treatment for hyperthyroidism. Surgical resection of the thyroid gland obviously removes (at least part of) the thyroid, resulting in the person being unable to make sufficient quantities of thyroid hormones. This results in the person being hypothyroid after the surgery, needing exogenous thyroid hormone for life. Interestingly, the parathyroids are located on the posterior aspect of the thyroid gland, which means thyroid resection typically results in loss of the parathyroids too, leading to deficiencies of parathyroid hormone as well. The same is true for radioactive ablation of the thyroid. MTR was completely correct in her statement.

  70. @MTR,

    There is no confusion. According to his beliefs, BJ was pre-determined to make that mistake. It’s just part of the natural world.

  71. BillyJoe says:


    Seems I did misunderstand. I thought you were talking about hypothyroidism/hashimotos which, as you will agree, is treated with thyroid hormone replacement, not surgery or radioactive iodine.


    None of what you said is news to me. ;)

  72. @BJ,

    I was going to reply to your comment, but you’ve already read it. :) (kidding)

  73. mousethatroared says:

    BillyJoe – Yes, I was sort of using shorthand because I remembered that Solandra had had thyroid surgery for a suspicious nodule and would know that thyroidectomy and radioiodine treatment means my friend had cancer.

    Yes, hashimoto’s hypothyroid is treated mostly with thyroid replace. But it’s good to remember that women with Hashimoto’s may be at an increased risk for thyroid cancer.

    Also, I remember my Endo telling me that some people with Hashimoto’s have “hot spot” nodules that produce excess amounts of thyroid hormone. I believe she said said that sometimes surgery is considered in those cases too. No idea how often that happens. I don’t have that, so we didn’t go into the details.

  74. mousethatroared says:

    SH – Thanks for the unsolicited observation about BillyJoe. But, I think we can work out our misunderstanding between ourselves, so no need to intervene.

    Seems like you missed Solandra’s comment that she was hypothyroid before concluding “There’s no way you are living like this and not losing weight”. I would guess that inquiring into her TSH level before dismissing her condition as irrelevant would be almost second nature to a doctor. I know that’s what every doctor I’ve seen has done.

  75. mousethatroared says:

    By the way SH – Due to my health concerns and my son’s, I belong to a number of forums of people with sometimes obscure or difficult to diagnose health conditions. I wonder if I should start sending more people over to this blog. It is very informative.

    If I were you, I might start being more careful judging on very little information whether a commenters health complaints are valid or not.

  76. jmb58 says:


    If the surgeon meticulously identifies all 4 parathyroids and uses autotransplantation when needed, permanent hypoparathyroidism should be rare (1%) after thyroidectomy.

    Maybe you are sending patients to the wrong surgeon (insert smiling winking face here).

  77. evilrobotxoxo says:

    How fat is too fat for bariatric surgery must depend heavily on which center is doing it. At least here at my institution in NYC, there are a surprising number of people whose BMIs are considered too high. IIRC, they won’t do bariatric surgeries on people with BMIs over 60 here. That might depend on the type of surgery and etc., but I’ve definitely seen more than a few of them.

  78. jmb58 says:


    As I think about it more I agree with you more than my post above. Most bariatric surgeons seem to say no after a BMI of 60. I was trying to give a guess on the upper limit of surgical feasibility. I think some of the super obesity centers will go higher or do an inpatient weight loss regimen and then surgery. I also agree there is an increasing number of these super morbidly obese patients.

  79. evilrobotxoxo says:

    @jmb: it’s true that I don’t know how many of these people there are, objectively. I obviously see a biased sample.

  80. Obesity and Obesogens..

    “The chemicals in non-organic foods can disrupt the endocrine system. (The endocrine system influences almost every cell, organ, and function of our bodies. It is instrumental in regulating mood, growth and development, metabolism), One type of chemical called Obesogens (OBESOGENS?! hmmm) disrupts the function of hormonal systems, leading to weight gain. Obesogens are derived from a variety of sources —hormones administered to animals, plastics in some food and drink packaging, ingredients added to processed foods as well as pesticides, herbicides and fungicides sprayed on produce. In addition, these chemicals are phytoestrogenic and xenoestrogenic, meaning they mimic estrogen in the body!. Estrogen is produced by fat cells, so excessive estrogen causes the body to become more insulin-resistant and create more fat cells.!! Cyclically, the fat cells produce more estrogen,!! causing the body to become more estrogen dominant.”

    !!super! more estrogen and more fat cells! (from eating sprayed “healthy” fruits and vegetables!).

    Antibiotics and Hormones

    (See all the appetite increasing agents going into our “healthy” food that go in us each day?)

    “Besides pesticide-sprayed animal feed, antibiotics and hormones are provided to animals on Concentrated Animal Feeding Operations, or CAFOs, the source of non-organic meats. The hormones that Make the (unhappy) Animals Gain Weight Faster can also Make (unhappy) People Gain Weight. These hormones are fed to animals to help reduce the waiting time and the amount of feed eaten by the animal before slaughter. The different kinds of steroid hormones (STEROIDS?!! I thought Congress was ‘against’ Steroids?!!:) that are currently used in food production in the United States include estradiol, progesterone, testosterone, trenbolone acetate, melengestrol acetate and zeranol, a commercial form of zearalenone, a Fusarium fungal toxin. In dairy cows, hormones such as the genetically engineered recombinant bovine growth hormone (rBHG) are used to increase milk production. Low-level feeding of antibiotics also promotes faster weight gain in animals raised for meat. Over a dozen antimicrobials are approved for farm animal growth promotion in the United States, including antibiotics that are utilized for treating human disease, such as penicillin, tetracycline and erythromycin”. ..How Do Organic Foods Help You Lose Weight) from

  81. mousethatroars..have you heard this…

    Fluoride causes Hypothyroidism..

    Fluoride causes Hashimoto’s Disease, one of the adverse health effects caused by fluoride added to our water. It took 35yrs before obvious symptoms of elevated cholesterol and TSH levels enabled diagnosis of thyroid dysfunction, ingesting unknown quantities of fluoride in water at levels considered to be “safe and effective”. The signs of low grade poisoning including fatigue, low energy, weight problems, urinary tract irritation and rashes were all there, for years prior to my diagnosis.


    Obesity and related problems are rife in Australia – everyone points the finger at diet but nobody suspects fluoride in the water. Fluoride impairs thyroid function resulting in imbalances in metabolism that contribute to weight problems.

  82. Evilrobotxoxoxo sezs:
    “I agree that we need something better than BMI, but the problem with the measure you’re proposing is that it will only work in people who are otherwise healthy. If a person has any sort of underlying heart or lung disease, then exercise tolerance is measuring something else entirely. ”

    1. Actually, for the sake of brevity, I left out details including the fact that normal adult active ppl will not be stressed by this activity. Older adults and the less fit will.

    2. The ‘something else entirely’ issue: if you go review the outcomes from people with various conditions and their heart rate variability (difficult to measure), including a much more wide range of conditions than you note, you will see negative outcomes such as rehospitalization or death much more comm on in those with low / poor HRV. Physical fitness is integrally confounded with severaity of illness across a wide range of diseases and conditions.

    I am not trying to be rude or know-it-all. A handful of us looked into a lot of HRV studies to come up with a ‘clinically meaningful difference’ in HRV, and we were stunned when we saw this phenomenon. Compared to everyday docs, I believe the docs who read this website get intrigued by curiosities such as this and will have their antennae out for info related to something interesting they learned while reading a blog, etc.

  83. Rustic Healthy: if fluoride causes Hashimoto’s, then everyone would have it.

    We all don’t.

    Obesity varies with a lot of caloric data such as avg exercise levels, sodas consumed, and video screen time.

  84. “My point stands: it is virtually impossible for someone to eat 1200 calories per day, burn at least 600 in exercise, and not lose weight (especially considering the whole thing about the body continuing to have increased caloric expenditure post exercise.) ”

    calories in-calories out is an over-simplification.

    Your weight level / fat level gets set by hormones, not by a process like your gas tank and car engine.

    1200 calories per day is a starvation diet, and sensing what the body perceives as famine conditions, it will not let go of fat.

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