The Cause of Obesity?

[anoopbal]

This might be a bit controversial, but I feel I have enough reasons. Just posting here because I think its is important. Let me know if you have any comments or questions.

Are obese people fat because they are lazy or because of their life style or their genes? - The Cause of Obesity

[nari]

Are obese people fat because they are lazy or because of their life style or their genes?

Complex question, Anoop. Maybe all three?
Certainly the genetic factor seems to be gaining in validity, but one sees obese parents with skinny kids nearing puberty, so when might the genetic factor kick in in that case??

A cynic might say there were no obese people in the concentration camps, but it may not be as simple as that. Some people find it really easy to lose weight by just eating much less, others cannot. Some will lose weight easily by eating less and exercising more, but in that case if they regress, the weight comes back on.

Epigenetics may also play a role; eg if one's grandparent was obese, does that pass on to the grandson and not the son??

Nari

[caro]

Man oh man Anoop. That is a loaded question.

I treat quite a few obese people. They refer me because I seem not ''to mind'' that they are obese. (I'm a Massage person BTW.) By obese, I mean well over 250 lbs for a less than 5''3 frame. Mostly women.

'' Go to her'' I imagine them saying, ''she won't bother you with the weight.''

And it's true. I never, ever bring up their weight. (But inevitably, it always comes up. Does it ever. I just listen. Never, ever advise.) Or their eating patterns. Not because I am better than anyone else but because of my own (weird) relationship with food and exercise I suppose.

I would say that for the most part, I don't really like to eat food. Except for some stuff (usually soft, mushy, sandwichey\ carbohydratey kind of fare) I could just eschew the whole process altogether if I had a choice quite frankly. But...

I am also one of those people who needs to move constantly. Constantly. So the organism needs fuel. Or else I get the ''shakes''. Basically, I live on bread, pasta, cheese, hummous, canned lentils (don't ask), bananas, almonds and peanut butter. As a kid, my mother literally had to force food on me. I've never been on a diet in my life. I have been heavier than I am now (more or less 115 for a 5'2 frame ) but never more than 130.

So very early on I figured if there are people like me (who could care less about eating food) there must be people for whom it's quite the opposite.

Eating is behavior and behavior well... Is pretty hard to change. (I've found eating patterns are very intimate and private. Probably one of the reasons why they are so hard to change.)

The people I treat are far from lazy. They are hard-working, dedicated professionals. They are individuals who manage their careers and family life very admirably.

For some reason, eating is something they enjoy. Eating is something that makes them feel safe. Eating is something they find pleasurable, that provides distraction. ( Sure beats the hell out of me.) Most, if not all of the obese people I treat are very, very lucid with regard to their obesity. They absolutely get that they are eating way to much in proportion to the energy they are expending. Some were quite thin and active in their youth. (read before kids) Many of them are quite knowledgeable in terms of nutrition and in all fairness, probably eat a more ''balanced'' diet than yours truly here, Miss ''Oh, crap it's 2:30, I've got 4 sessions lined up and I haven't bothered to ingest a morsel.'' ...

[ovpt]

any of the above reasons can lead to obesity among other reasons such as medication reactions, thyroid disease, etc. genetics and lifestyle can also be difficult to differential when looking at cultural biases. Definitely a slippery slope to try pin down.

[nari]

Carol,
I can identify with your thoughts, easily. I basically eat in order to stay in one piece, food is a necessity not a gourmet adventure.
I also move around a lot and can't sit in a cinema to watch a 3 hour film to save my life.
{I'm 5ft5ins and weigh 53 kg (116.8 lbs for those Imperialists)}

Barrett might have something to say something about my adaptive potential...oh well.

When I worked, I also never broached the question of obesity/overweightness in patients unless they asked first. Not my scene and there is little evidence that overweight people have more pain than the norm. Plenty of skinny people have joint degeneration resulting in pain, though it could be argued that pain can be the result of underactivity and overactivity.

Nari

[Jon Newman]

I used to be someone who thought he didn't enjoy eating but I lost my ability to taste food for a little while and I learned fairly quickly that I enjoyed eating much more than I realized. Joni Mitchell was right when she sang "don't it always seem to go you don't know what you got 'till it's gone."

I think there is a difference between having an "eat to live, not live to eat" attitude and not actually enjoying food.

[Diane]

Food deprivation makes me feel depressed, which is why I tend to be way too chubby.
I think I'm slowly outgrowing it though (need to eat to feel better, temporarily). Moving away from the rainforest has helped quite a lot.

[nari]

I'm wondering about the connection between a rainforest and need for food?
I should add that if I had to go without chocolate every day, I'd probably be depressed too!

Nari

[anoopbal]

Hi Nari & ovpt,

I don’t think anybody disagrees that they are all contributing. The question is which is the major contributor.

And why should obese parents not have skinny kids? Even short people have tall kids though it isn't the norm. That just shows how theseheritable traits are due to interactions of multiple genes. The same goes for parents who have both fat and lean kids.

The lack of obese people in a concentration camp is just an of example of the absence of environment.

Epigenetics may play a role. Part of 20% -30% in twin studies is attributed to unshared environment includes these factors in the intra uterine environment.

And why think about special circumstances and coming with personal hypothesis when we know there are number of twin studies done to answer these very questions. We just have to look at what these studies say since they are THE only way to even out the playing feild. This is the classic way of identifying the hereditary contribution of different traits.

And I am not talking about 15-20 lbs weight gain people experience. And most people use these modest weight losses as a frame of reference and just casually extrapolate it to obesity. I am just below being overweight and I have to gain around 50 lbs to be obese! I don’t think I can ever do that even If I badly want to. Now think eating like that for the rest of your life. So people don’t get accidentally obese.

And you cannot compare obesity to traits like hieght or IQ. Genes aren't sitting there silently under they see the right environment. Obese people eat because they are extremely hungry. We used to think that obesity is just because of a slow metabolism. But now we know that it is (and slow metabolism) hunger which is driving these people to eat. Part of the reason bariatric surgery works is by blunting appetite throgh some unknown mechanisms

It is extremely hard for people to understand that losing 50-100lbs for an obese person is very similar to a lean person losing 50-100 lbs.

[Diane]

People are trying to incriminate the hypothalamus, then fix it with homone-laced chewing gum.

Whatever.

The hypothalamus works way better when the suprachiasmatic nucleus gets enough light stimulation. At least mine seems to.

[Barrett Dorko]

We will struggle with this topic as long as we’re looking for cause. That, in my experience, is a mistaken way to begin any search.

Two things: Weight is a consequence of mathematical addition and subtraction – no exceptions.

Our instinct to eat more of what makes us obese is detailed in this thread.

I’m sure you know that obesity is a huge problem in our culture. It touches everyone and “solving” this problem is a gigantic industry. I’ve recently heard that it can be a consequence of hunger and poverty.

It’s not going anywhere.

[Bas Asselbergs]

I love food and eating. The tastes from all over the world are found in my home - I love to cook, eat and share with others. I eat almost anything and sometimes a lot of it.
I am 6 ft tall and 172 lbs. Not fat or obese.
So, now that that disclosure is out of the way, some comments about genetics.

My wife is slender. Our daughter who eats small amounts of very healthy foods is chubby. My mom and dad, and fraternal grandparents were slender, yet my sisters are chubby; one has a chubby daughter the other a supermodel daughter. Yeah: huh?!

I can't figure the whole obesity thing, other than the food amounts and lack of exercise in North America play a HUGE role (pun intended).

[joebrence9]

Two things: Weight is a consequence of mathematical addition and subtraction – no exceptions.

Our instinct to eat more of what makes us obese is detailed in this thread.

I agree. If you have ever watched The Biggest Loser, you have likely never seen a contestant be unsuccessful. This is because they are burning more calories than they are consuming. I would suspect if it was a causative relationship of genetics/thyroid and obesity, then this would be impossible.

I would blame social context more than genetics. Obese parents will have obese children likely because the environment in which they raise them vs. passing on fat genes.

I believe alot of people like to blame other things vs. their eating patterns/lack of activity...So maybe we can make obese people feel better by telling them their obesity is caused by an adenovirus...(http://www.livescience.com/595-obesi...cientists.html)

[anoopbal]

I love food and eating. The tastes from all over the world are found in my home - I love to cook, eat and share with others. I eat almost anything and sometimes a lot of it.
I am 6 ft tall and 172 lbs. Not fat or obese.
So, now that that disclosure is out of the way, some comments about genetics.

My wife is slender. Our daughter who eats small amounts of very healthy foods is chubby. My mom and dad, and fraternal grandparents were slender, yet my sisters are chubby; one has a chubby daughter the other a supermodel daughter. Yeah: huh?!

Hi Bas,

There are multiple genes controlling traits like obesity, maybe 100's. The interaction is always complex and not like single gene traits like eye color.

What does that tell you? That you can have the same shared family environment, but totally different fatness levels. That is one example of the biological basis of obesity, don't you think?

[anoopbal]

I agree. If you have ever watched The Biggest Loser, you have likely never seen a contestant be unsuccessful. This is because they are burning more calories than they are consuming. I would suspect if it was a causative relationship of genetics/thyroid and obesity, then this would be impossible.

I would blame social context more than genetics. Obese parents will have obese children likely because the environment in which they raise them vs. passing on fat genes.

I believe alot of people like to blame other things vs. their eating patterns/lack of activity...So maybe we can make obese people feel better by telling them their obesity is caused by an adenovirus

Have you seen them after 1-3 years? Most of them gain it all back. It is pretty black and white in research that almost all obese people gain most of their back within 1-2 years. The further you move away from your set point, the stronger your body tries to get you back to your set point.

On what basis are you blaming parents? It is pretty clear in research that childhood obesity has a strong heritable component. The environement has only a small role to play. And almost of the effects of the shared environement dissapears as they grow up. Most of the environment effect is explained by the unshared environment (kids in the same family making different choices when it comes to food and activity).

And everyone knows obese people are fat because they eat too much and move less. The million dollar question is why are they doing this in the first place?

And did anyone read the article? (:-

[joebrence9]

Anoop,
I read the article and I will preface by stating I am not an expert on obesity,but I do have 2 undergraduate degrees in Cell Biology and Health Sciences and have taken a few upper level genetics courses.

I don't think anyone will argue that genetics has a role in giving us many of our bodily traits. I do believe obesity is multifactorial of inherited allelic variation with environmental influence and that we have control over modulation of the environmental variables.

I think we can compare obesity loosly to vision. We may be born with bad eyes from a genetic defect, but we can opt to enhance vision through corrective lenses. We can utilize tools to make up for the defect.

I am curious why many individuals opt out of taking control of their obesity. Is this a genetic defect in the frontal lobe?

[MaxG]

What about people who lose a lot of weight and keep it off?

These folks are clearly the minority, around 5-10%. It is not exactly clear how they do it .There might be a subset of people whose conscious motivation can override their biological drive in the long run. Majority of the people can’t.

Isn't that what "will power" is about?
How is it not "will power" if obese people can lose weight but don't manage to keep it off because of increased "biological drive" to gain it back?


Though there certainly are genes responsible for how we process food and for our "biological hunger drive", isn't that like saying we're predisposed to feeling tired when the sun goes down (in the abscence of artificial light sources), but some people manage to stay awake longer against their "biological drive to sleep"?


Ergo, isn't the final determining factor in obesity behaviour, regardless of genetic predisposition?

[anoopbal]

Hi Joe,

I think the important point to note in your post "that we have control over modulation of the environmental variables."

We used to believe that obesity was because of metabolism defects or slow metabolism and such and obese people just simply had to eat less. Now it is clear that the major driving point for obesity is hunger (and metabolism). In leptin deficient kids, the drop in weight is largely due to to the blunting of their voracious appetite and thereby eating less. Another example is the with Prader-Willi syndrome where they eat even from the garbage cans. Their families have to keep the refrigerator and cupboards locked because these kids cannot control. Another example is how bariatric surgery works is by blunting of appetite by some unknown mechanism. It is now clear that with the same food intake and same physical activity in controlled conditions people identical twins gain different and lose different weights.

And this is the problem with comparing obesity to other genetic traits. Phenyl Ketone urea is a classic example of how environment can offset the genetics. BUT these kids don't have a voracious appetite for the amino acid phenylalanine.

And we should be careful when we blame obesity on parents. Case in point, in 2009 in UK 4 families were almost on the verge of losing their children and their whole life being shattered. Their kids were obese and the social workers were blaming it on abuse and neglect. The authorities were later informed by researchers that these kids had a genetic mutation causing the weight gain.

I am curious why many individuals opt out of taking control of their obesity. Is this a genetic defect in the frontal lobe?

That is a good point. Finally it all comes down to the unconscious biological drive vs your conscious motivation to lose weight. For most people, in the long run, the biological drive finally wins. For a minority, it is the other way. It would be nice to know how these interacts in the brain and where.

[Diane]

Dorsolateral prefrontal cortex is the only zone in the frontal lobes that can disengage itself and consider possibilities, deliberately choose a behaviour, then re-engage and commandeer the other brain parts to do its/their (there's one on each side) bidding.

[ovpt]

Look at China. Childhood obesity is a surging problem in the larger cities. Considering the one child rule creates a higher percentage of caregivers/supporters to each child and the increase in westernized fast food availability. they dont have the same obesity problems in the rural areas.

[byronselorme]

Gary Taubes released a book earlier this year called Why We Get Fat. I noticed your mention of the Pima above, that was one of his big case studies.

Harriet Hall had a good time debunking most of his book here, although her advice falls back to the old standard.

I don't know if you read Sapolsky's Why Zebras Don't get Ulcers, he had a section discussing the effects of the parents environment on fetal development. I forget which country he mentioned, but there was someplace like Poland during WWII that had their food supply cut off. The resulting children of that generation had enormous health problems (including obesity I believe) and I think one of the hypotheses was that in a maternal system that is not receiving enough nutrition, the fetus learns to be very thrifty with its food supply. In later years that can result in that concept of the slow metabolism.

Of course I think that can all be part of a complex problem, and I don't know if there is a seed of the answer in any of that.

Great article, I had not heard of that Leptin hypothesis or testing before.

[zimney3pt]

Anoop, enjoyed your article, but I think some of your recommendations should be the title and focus of your article (I think they deliver the message that needs to be told).

1. We should focus more on health than weight or the cosmetic aspects.
2. It is clear than moderate weight loss of 10-15 lbs of weight loss in obese people can have dramatic improvements in their health.
3. It is also very clear that eating healthy and exercising has a beneficial effect on health independent of the change in body weight.

The focus needs to be less on the weight number and more on am I practicing healthy habits to be fit and worry less about if I am fat. Even if the healthy habits don't change your weight (because of your genetics or other reasons) we should not stop them. Which I think many people do. People incorrectly associate being overweight will cause you to be unhealthy. So most people will conclude if I exercise and eat better and my weight doesn't change, then I am still unhealthy. Rightfully so, they would think, why eat right and exercise if it doesn't change my health. So they often times part take in all sorts of unhealthy practices in a vein attempt to get the number down (just look at much of the diet and fitness industry focus to get thin and less on getting fit).

The problem I see with pointing to a cause of obesity, whatever may be the more significant factor, is that people may decrease self responsibility to being healthy and more fit (which consists of basics of exercise, eating well balanced controlled portions, and reducing stress). People will use arguments to talk themselves out of healthy practices since we incorrectly associate what I weigh directly with if I am healthy or not: "I have obese parents so I am obese and there isn't much I can do about it." "It is to hard to change my lifestyle, so there isn't much I can do about it." "If I exercise or change diet I will eventually go back to my same weight so why bother."

Societally the battle to decrease the buldge is because of the financial costs associated with health problems (diabetes, stroke, heart risks, and others) linked to obesity. Personal battles are often times associated with the vain cultural view of thin being in and more attractive. But the research shows more that the health status of the individual is more tied to their fitness and less to their fatness. [Side note, if you tip the scale to far and enter into the obese range is where the majority of health problems begin. I have not seen many obese people that are fit (exercising regularly and controlling diet properly), but I have seen lots of fit people that may be overweight and think they still need to lose 10-15 pounds to get to their "healthy" weight.]. Wouldn't it be great if we could change the cultural view to being fit and healthy is in no matter what your weight was? Maybe we would see a drop in some of those health problems?

As the cause of being overweight will likely continue to have arguments from different perspectives, here is an alternative argument from Anoop's. I would like to see more attention put to being fit and less worry over if you are fat. Let the weight number fall where it needs to fall, but just get a little more fit.

[Barrett Dorko]

The further you move away from your set point, the stronger your body tries to get you back to your set point.

Wrong.

[anoopbal]

Gary Taubes released a book earlier this year called Why We Get Fat. I noticed your mention of the Pima above, that was one of his big case studies.

Harriet Hall had a good time debunking most of his book here, although her advice falls back to the old standard.

I don't know if you read Sapolsky's Why Zebras Don't get Ulcers, he had a section discussing the effects of the parents environment on fetal development. I forget which country he mentioned, but there was someplace like Poland during WWII that had their food supply cut off. The resulting children of that generation had enormous health problems (including obesity I believe) and I think one of the hypotheses was that in a maternal system that is not receiving enough nutrition, the fetus learns to be very thrifty with its food supply. In later years that can result in that concept of the slow metabolism.

Of course I think that can all be part of a complex problem, and I don't know if there is a seed of the answer in any of that.

Great article, I had not heard of that Leptin hypothesis or testing before

Thanks!!

I don't think people who study obesity or know about obesity ever take Taubes seriously. I haven't read sapolsy's book, but I have a heard a lot about it. It goes back to the epigenetics question.

And what is missing in this discussion is how do we study the heritabality issue than casually bringing in your own personal observation and anecdotes. All the examples people give cannot be used to tease out the contribution of genetics or environement.

Twin studies are used to do this because identical twins are almost 100% similar and non-identical twins are 50% similar. Identical twins have the same genes and same family environment, whereas non-identical twins have the same environment but different genes. Any difference between these two shows us the heritability of the trait. Identical twins reared apart in different families shows how environment can affect traits. And this is where we get these percentages from.

And I have given a lot of other evidences for the biological basis of obesity. There are a few researchers who supports this view: Friedmann and Farooqi to name a few. Friedman discovered Leptin and almost missed the Nobel prize last year.

[anoopbal]

Thanks Kory!!

This may be the very few articles out there which emphasizes the role of genetics in obesity. What you see is an endless list of books and articles which blames obesity on fructose, carbs, fat, poor lifestyle, will power, moral choices and so forth. It is now very well known that obese people are discriminated in the society. They lack self esteem and confidence because the world has convinced them it is their personal failing. I have clients who are embarrassed and humiliated to tell me that they again ate because they were hungry and failed. So I would say the balance is fairly tilted in the other direction. But I do agree your major point.

You make a lot of good points about the fitness vs fatness debate.

And as I wrote the increase in obesity in the recent years is true, but this is due to nature of assigning a mathematical cut off to a biological trait. Though in 2000 there was a 33% increase in obesity compared to the previous, the average weight increase was around 10-15lbs. But that is enough to push a lot of people over the 30 BMI mark. This small increase paints a whole new picture compared to when you hear the "33% increase in obesity", right?

[anoopbal]

Wrong.

Hi Barrett,

Would you care to explain why?

[zimney3pt]

This small increase paints a whole new picture compared to when you hear the "33% increase in obesity", right?

Absolutely. Again, why I think if we could put more attention to being fit and less about the number.

I can't speak for Barrett, but why I would say that statement is wrong...is because it is the brain that decides 100% of the time not the body. Hunger, thirst and pain all are outputs of the brain. The hunger you feel to bring you back to that set point is an output of the brain.

[Diane]

Originally Posted by zimney3pt

it is the brain that decides 100% of the time not the body. Hunger, thirst and pain all are outputs of the brain. The hunger you feel to bring you back to that set point is an output of the brain.

Which leads to a preliminary conclusion that obesity is biopsychosocial.

[Barrett Dorko]

Brain, not body.

No small distinction.

[Jon Newman]

I consider the brain part of the body but not part of the mesoderm or endoderm.

[Diane]

Originally Posted by Jon Newman

I consider the brain part of the body but not part of the mesoderm or endoderm.

I agree.
Separating brain and body seems a bit too Cartesian these days.

[nari]

I think somewhere along the line, the body image gets distorted, in the same way that anorexics see themselves as fat.

Some women who wear size 22 (or more) clothing seem unconcerned about it, as though it's their destiny to be fat. If they are unhappy about it, it doesn't show; they make no attempt to change their ways and laugh it off while having a third helping of dessert. I know several women in our extended family who do just this. One attempted to eat 50% less for a week and nothing happened (surprise, surprise!) so she went back to old habits, quite cheerfully.

It's as though their brains and the mirror assure them that they are fat and it's OK.

Nari

[anoopbal]

it is the brain that decides 100% of the time not the body. Hunger, thirst and pain all are outputs of the brain. The hunger you feel to bring you back to that set point is an output of the brain.

I agree. Leptin is a chief player here in the long term modulation body weight and hunger. Ghrelin, CCK and other gut hormones are the short term modulators of hunger.

But my point is that your body weight is maintained within a range by powerful physiological signals. The further you move from that range, the harder it becomes. There was a recent study that showed how even after a year leptin, ghrelin, and hunger were all significantly below than when they started the diet a year back.

[Diane]

Originally Posted by nari

I think somewhere along the line, the body image gets distorted, in the same way that anorexics see themselves as fat.

Some women who wear size 22 (or more) clothing seem unconcerned about it, as though it's their destiny to be fat. If they are unhappy about it, it doesn't show; they make no attempt to change their ways and laugh it off while having a third helping of dessert. I know several women in our extended family who do just this. One attempted to eat 50% less for a week and nothing happened (surprise, surprise!) so she went back to old habits, quite cheerfully.

It's as though their brains and the mirror assure them that they are fat and it's OK.

Nari

Quite true. One doesn't "feel" fat, one feels quite normal, kinesthetically speaking. One minimizes clear signs, such as tight clothing, by extroverting them, seeing the situation as being the fault of the clothing. "Those pants are too tight", or, "These pants must have shrunk somehow", not "Gee I must have become too big for these pants". Activities that would put one out of breath are routinely unconsciously avoided with the idea that life is too short and already too full of stress and woe to invite more of the same by way of physical struggle, not engaged consciously as challenges to actively conquer in order to maintain or to acquire health. Food is used as a mood-altering substance - it's cheap, available, and works. Mothers taught chubbos this trick from babyhood, non-verbally, and emotionally. It takes a long time to deconstruct such engrained habits.
And these are just some of the cognitive habits that go with obesity. Biopsychosocial.

[Nairb]

Hi Anoop,

If that study you are talking about is this one

http://www.nejm.org/doi/full/10.1056/NEJMoa1105816

then the subjects were put on a highly calorie restricted diet. This diet would simulate a severe food shortage, so it is not surprising that the body/brain over-reacts afterwards. Has there ever been a study with slow healthy changes in diet and lifestyle that showed the same long term biochemical changes?

[Barrett Dorko]

Great discussion.

I would never imply that losing weight is easy by any means. For all the reasons mentioned it is difficult and, in today's culture, more so every day.

I'm currently working in a facility where I would conservatively estimate that 75% of all conversation among the staff is about food and 75% of them are morbidly obese.

I think that's just a coincidence though.

[Ben Sabo]

Originally Posted by anoopbal

Have you seen them after 1-3 years? Most of them gain it all back. It is pretty black and white in research that almost all obese people gain most of their back within 1-2 years. The further you move away from your set point, the stronger your body tries to get you back to your set point.

Isn't that true of most people who lose weight? Looking at this from a slightly different angle, what about the experienced strength athlete or bodybuilder who gets seriously injured and loses a lot of muscle mass during their time off? Once they resume their training, they can recover lost muscle and strength in much less time than it took to initially build it. Which is being defended in that case: a genetic "set point" or a behavioral "settling point?"

Assuming that weight loss is a priority for someone, most people go about it in the wrong way and the obese are no exception. You can't eat at a caloric deficit forever; at some point you have to eat at maintenance levels. This will necessarily require an increase in physical activity to maintain that weight, either in frequency or intensity, and this usually doesn't happen. The typical dieter reaches their weight loss goal and thinks their work is done. Then, once they put 10, 20, 30 pounds back on, it seems pointless to try to do anything about it. Thermodynamically, it's no surprise that most people regain the weight they lost, regardless of the amount. That fact alone doesn't support the genetic basis for obesity, IMO.

Which leads to a preliminary conclusion that obesity is biopsychosocial.

I like where this is going. Hunger, like pain, obviously serves a protective function. Regardless of where your starting point is, it's generally harder to lose weight than to gain it, and it only gets harder as you get leaner. If food has been used as an emotional crutch for years, it makes sense that the brain could perceive any weight loss or even the absence of food as a threat.

[Ryan Appell]

I took a class on obesity a while back in undergrad, the consensus at that time seemed to be that the rising rate of obesity was mostly due to environmental contribution, primarily because of the short amount of time in which it has increased. I think the point was that the rate of increase suggests a strong environmental role, but that the incidence of obesity is probably more genetically determined. That's pretty much all I got out of that class, I probably should have paid more attention.

I've been reading Doidge's The Brain that Changes Itself, and it makes me wonder, if hunger is just an output from the brain, then wouldn't it make sense that slow and healthy alterations in diet and activity level could change the brain's "set point" for outputting a hunger signal? Perhaps obesity, and weight loss in general, could benefit from a better understanding of the brain's role in hunger? Is the "set point" something that we have limited control over? Or do our brain's have sufficient plasticity to change themselves enough to not output hunger?

Regardless of whether environment or genetics play a larger role, I think the fitness vs. fatness point is the main thing I take out of the research. I can't help you change your genes, but I can help you get fit, which will help you a lot more than a smaller number on the scale.

[byronselorme]

I remember attending a lecture where the Psychiatrist was discussing the role of Serotonin release from certain foods and the satiety that was attained by searching for and consuming foods that filled a larger release then others. Obviously 1000 years ago, fat, salt, and sugar would not have been easy to come by. It would make plenty of sense for a successful species to be particularly good and searching, finding, and consuming these types of foods.

I abandoned Taube's book about 3/4 of the way through. His data seemed to be cherry picked and some of his descriptions looked like they needed a thorough debunking. It was right about that time that Harriet Hall blasted his book.

It is why I started looking into sites similar to highsatiety.com. Finding out how food makes you feel satisfied vs just getting adequate nutrition @ minimum calories. I think a Neuromatrix could well be developed or used for this as well. Food is a cultural, sensual experience as well as a necessity. Big changes will always violate the potential for it to last. NeuroElasticity is the biggest enemy in this case (I would wager that it is more important than searching for a biological set point).

PBS had an interesting documentary about this as well. Fat: What no one is telling you. In it they discussed exactly what Kory was saying about fitness being the more important focus.

[anoopbal]

Hi Anoop,

If that study you are talking about is this one

http://www.nejm.org/doi/full/10.1056/NEJMoa1105816

then the subjects were put on a highly calorie restricted diet. This diet would simulate a severe food shortage, so it is not surprising that the body/brain over-reacts afterwards. Has there ever been a study with slow healthy changes in diet and lifestyle that showed the same long term biochemical changes?

Hey Nairb,

In fact they were on a VLCD - Very Low Calorie diet which is often prescribed for obese people and is 'moderately' effective in weight loss. In fact, there are reviews which shows that VLCD and LCD are equally beneficial. I don't think anyone has shown that one is way superior over the other.

And look at the bigger picture, whether you are doing a moderate or very low calorie diet, people gain most of it back within 1-2 years. And leptin levels are manly dictated by your body fat levels. There is no research to show that slowing down the body fat loss can decrease down the drop in leptin.

[MaxG]

One probem I have with the focus on genetics in obesity is that not only doesn't empower the sufferer, it practically takes his responsibility away from him.

No matter how scewed ones leptin levels, it doesn't just put on 100lbs of weight on you. There has to be more at play (biopsychosocial).

A similar notion would excuse all sufferers of any type of addiction.
Say, smokers for example. They feel a strong urge to consume cigarettes, much stronger than non-smokers. There are genetic factors at play in developing an addiction.
Ergo, smokers are unjustly stigmatized, because their genes made them become addicted and thus they are not at fault if they keep smoking!

I can not agree with that logic. I surely don't want to unnecessarily stigmatize obese people and compare them directly to smokers. But there are definite drawbacks, IMO, to being obese (not just overweight); health problems, less mobility in everyday life, for example.
There also is a solution to being obese, and that is losing weight.
Here, the smoker's analogy seems appropriate, as there are many many smokers trying to quit, but few keep their sobriety up. Does that mean one should discourage a smoker from quitting, "because with all likelihood it won't work anyways"?

[Diane]

Originally Posted by Barrett Dorko

I'm currently working in a facility where I would conservatively estimate that 75% of all conversation among the staff is about food and 75% of them are morbidly obese.

I think that's just a coincidence though.

It looks like a one-to-one correlation.
Which is also why it's good to remember correlation is not causation.

[anoopbal]

Isn't that true of most people who lose weight? Looking at this from a slightly different angle, what about the experienced strength athlete or bodybuilder who gets seriously injured and loses a lot of muscle mass during their time off? Once they resume their training, they can recover lost muscle and strength in much less time than it took to initially build it. Which is being defended in that case: a genetic "set point" or a behavioral "settling point?"

Hi Ben,

I think we see have seen some physiological mechanism for muscle memory. The muscle still maintains the myonuclie in the cell which makes it easier to get back. And these comparisons always fail since fat and muscle have way different physiological mechanisms. We now know that fat is an endocrine organ as well.

Assuming that weight loss is a priority for someone, most people go about it in the wrong way and the obese are no exception. You can't eat at a caloric deficit forever; at some point you have to eat at maintenance levels. This will necessarily require an increase in physical activity to maintain that weight, either in frequency or intensity, and this usually doesn't happen. The typical dieter reaches their weight loss goal and thinks their work is done. Then, once they put 10, 20, 30 pounds back on, it seems pointless to try to do anything about it. Thermodynamically, it's no surprise that most people regain the weight they lost, regardless of the amount. That fact alone doesn't support the genetic basis for obesity, IMO

When you lose weight, there is also a decrease in caloric expenditure which is not proportionate to the loss of body weight. Leptin seems to have an effect on both sides of the equation. And it s pretty much known that exercise do not burn enough calories to compensate for diet. And there has been numerous studies done with diet AND exercise which is marginally more effective than diet alone.

[nari]

One possible solution, though ethically dubious, is to send a group of obese people on a trek in Antarctica over 2 weeks or so.

Apparently at -40C (-40F) and walking each day on a calorie consumption of 7500 per day, weight loss is considerable and very slow to recover. Canadians and Russians could do this on a regular basis and maybe their brains will rethink their programming.

Nari

[anoopbal]

The anorexic example is an example about how finally it is a battle between higher cognitive signals and the biological drive. Theese are exceptions where the stimulus is so strong that it could override the basic drive. And there might be some genetic factors that make people who have these psychological constructs to predispose them to anorexia and so forth. I know quite a few studies have looked at these connections.

And we have animal studies which clearly shows a biological basis of obesity. These animals are immune to cultural and social effects. We would have seen these in the twin studies if indeed these psychological and social aspects had a major effect on obesity.

And it is all a matter of degrees. Heritability of height is 90%. Heritability of BMI is 70-80%. That 20-30% percent may well include the psychosocial effect.

[MaxG]

Originally Posted by anoopbal

And it is all a matter of degrees. Heritability of height is 90%. Heritability of BMI is 70-80%. That 20-30% percent may well include the psychosocial effect.

I would be very carefull with such conclusions.
Many traits are passed on to following generations, not all of them on a genetic basis and not all of them unchangeable.
It is hard to change your height much by modifying habits, it is possible though to modify your BMI.

[Barrett Dorko]

I wonder if anyone here might like to comment on this ad. It was placed on the table of a local chain restaurant.

[Diane]

"You will be assimilated."

[anoopbal]

I would be very carefull with such conclusions.
Many traits are passed on to following generations, not all of them on a genetic basis and not all of them unchangeable.
It is hard to change your height much by modifying habits, it is possible though to modify your BMI.

It is not MY conclusions based on my biased observations. These are from twin studies which have been done all over the world for decades to study heritability.

If you have a problem with the validity of twin studies, we have a bigger problem here which might shake the whole foundation of how heritability and nature vs nurture is studied.

Height has changed throughout decades in US. It has gone up from 5 8 till 5 10 from the 1800. Malnutrition can stunt a child's height too.

And try losing 40-50lbs and keeping it off for atleat 3-4 years. That is just 3-4 units in BMI. It probably won't change anything, but will give a different perspective about the word "possible".

[anoopbal]

Great discussion.

I would never imply that losing weight is easy by any means. For all the reasons mentioned it is difficult and, in today's culture, more so every day.

I'm currently working in a facility where I would conservatively estimate that 75% of all conversation among the staff is about food and 75% of them are morbidly obese.

I think that's just a coincidence though.

Thanks, Barrett!

Interestingly, people who lose a lot of weight act the same way. In the famous Minnesota starvation study, by the end of 6 months, the subjects were constantly thinking, talking and dreaming about food. Obese people are always in a leptin deprived state like dieters.

In the leptin animal studies, the leptin deficient rat that got the leptin injections start moving around in the cage like normal rats, even before they lost a lot of weight. On the other hand, the leptin deficient rat that got the saline is always sitting with no movement. It just one way leptin affects the energy expenditure side of the equation.