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It really is in your genes!

  1. Aug 28, 2006 #1

    selfAdjoint

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    Are you a persistent drunk? Have you not seen your toes since you were a kid? You like to blame it on your genes, right? Now see this (new paper in the wonderfully titled journal Molecular Psychiatry - only the abstract is free, but that should suffice.

    http://www.nature.com/mp/journal/v11/n9/abs/4001856a.html
     
  2. jcsd
  3. Aug 28, 2006 #2
    Wow thats awesome, the genetic front is really pushing on and ahead into greater things.
     
  4. Aug 28, 2006 #3

    chroot

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    Obesity used to be a rare disease, but has risen so rapidly that it affects nearly half the US population -- after only a couple of generations. Is obesity heritable? Give me a break.

    - Warren
     
  5. Aug 28, 2006 #4

    Bystander

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    PC genetics --- nothing is anyone's fault. Strange twist on Cotton Mather's (?) "Sinners in the hands of an angry god" determinism.
     
  6. Aug 28, 2006 #5

    selfAdjoint

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    "I refuse to look at this experimental evidence because
    a) I know better, and
    b) I have an oversimplified argument which attacks a straw man version not present in the paper."

    Give ME a break!
     
  7. Aug 28, 2006 #6

    chroot

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    If you don't eat it, it can't end up on your thighs. It's the conservation of mass, selfAdjoint. Regardless of any proof of genetic predisposition towards, say, food addiction, virtually all fat people are fat because they eat too much. Period. There really cannot be much debate about this.

    - Warren
     
  8. Aug 28, 2006 #7
    With all due respect to your status on PF--there is widespead evidence of genetic desposition to obesity--I provide a few reports below. As stated in link #3 below, obesity is not a simple lack of free will responsibility--but a very complex disease that now effects vast numbers of humans:
    http://hmg.oxfordjournals.org/cgi/content/abstract/ddl204v1
    http://www.ncbi.nlm.nih.gov/entrez/...ve&db=PubMed&list_uids=11087657&dopt=Abstract
    http://www.muhealth.org/weightlosssurgery/understanding.shtml
    http://query.nytimes.com/gst/fullpage.html?sec=health&res=9904EFDB173FF93BA25757C0A9609C8B63
     
    Last edited by a moderator: Aug 28, 2006
  9. Aug 28, 2006 #8
    But what drives those people to eat more and more? If they're eating because they're depressed, then why choosing eating, and not say - cutting - when depressed?
     
  10. Aug 28, 2006 #9

    selfAdjoint

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    My family tends to run to weight. When I was married my weight hovered just above 270, and my wife was fat too. Was it because we ate too much? You betcha! And I drank too much also. My two children also tend to put it on, and the tendency has descended to my eldest grandaughter. Too much eating? Yes indeed!

    But since I've been a widower I've lost 100 lbs; my weight now hovers just above 170 and my BMI is between 21 and 22. Eating less? That's how I did it.

    But a while back I was talking to my kids and I mentioned that I almost never feel hungry, or full. When I read about tricks for "satisfying your appetite" with low calorie food, I am bemused, because as far as I've ever been able to tell, I have no appetite. I don't eat to feel less hungry, I eat for mouth sensations; taste texture and so-on. And I have lost that weight by exploiting this trait; I eat very little mass and drink a lot of fluids. Mostly water.

    And when I said these things to my kids they responded: "That's the way we are too!" Does this lack of a clear signal from our digestion maybe have a bearing on our weight problems? Could be. And if so, might there be a connection to dopamine processing in the brain? Not unthinkable. And if THAT is so, could there be a genetic reason for it? Yup.

    "Make everything as simple as possible, but not more simple than possible".
     
    Last edited: Aug 28, 2006
  11. Aug 28, 2006 #10
    They are not eating more and more--they are eating less and less of proper molecules in balance. See the third link provided above--the genetics for obesity has always been present for > 50,000 years in humans--excessive fatty molecules in modern diet act as trigger to activate genes that allow fatty tissue to accumulate out of proposition to the mass eaten. Now add on lack of exercise (e.g., too many folks typing on PF:smile: ) and here we are--modern day epidemic. Good news--if genetic based--then genetic cure possible.
     
  12. Aug 28, 2006 #11

    chroot

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    Do you dispute my statement that, if you do not eat it, it cannot end up on your thighs?

    Do you dispute my statement that the vast majority of fat people would lose weight if they simply began expending more calories than they consume?

    In this western world, we're in an age of almost universal literacy, universal nutrition labels, easy access to healthy foods in well-stocked supermarkets, and cheap food scales. There is absolutely no excuse for anyone to "accidentally" eat 300 lbs more food than they need. If people claim their bodies cannot self-regulate via normal hunger and satiety stimuli, then they can buy a damn food scale, or read the nutrition labels, and use their brains instead. This is assuredly NOT rocket science, and we don't need any deep genetic studies showing us how it's "okay" to be porkers. Obesity is not a disease of the genes, it's a disease of the fork.

    - Warren
     
  13. Aug 28, 2006 #12
    I think it's pretty obvious that biology determines how much you like alcohol. Some people from all sorts of environments just don't need or want it. Observations of primates that trespass on public beaches and steal people's drinks also show that the same proportion of them prefer alcohol as the human population.

    Whether there is a recognizable biology for the abuse of alcohol is sketchy. Obviously, the more you like it, the more likely you are to abuse it, but that's hardly a determining factor. Some people who don't like it still abuse it, likely as a means of fitting in.

    Well, you're right, regarding the fact that good scientific answers are ultimately not debatable, but biological systems do not treat mass equally, the way a physicist does. Your body does not treat all mass the same, nor does your body treat certain kinds of mass the same as another person's body might. Just because obesity is correlated with mass doesn't mean it's physics.

    You've probably seen people eat ridiculous amounts of food, not do any exercise, and remain thin as a rod. That's because they were born with an ectomorphic biology. Such people are annoyed when you marvel at how thin they are. It's not something that's up to them, and they'd probably rather have a more muscular and mesomorphic body.

    Anyway, I don't think genes are the biggest problem in the obesity epidemic. It's a hugely subsidized sugar industry, creating an evolutionary shocking surplus of cheap refined sugar products. This affects lower income people more, because they naturally want to maximize the amount of energy they receive per dollar spent. Homo sapiens evolved in an environment where sugar was not as plentiful, so we adapted mechanisms to store it. These mechanisms have gradually become unnecessary. However, subsidizing the sugar industry accelerated this change and created a hostile environment, which people are still trying to adapt to.

    Instead of wasting time and energy adapting to a hostile environment, we should just remove the subsidies, so that we can spend more time and energy adapting to natural changes.
     
    Last edited: Aug 28, 2006
  14. Aug 29, 2006 #13

    selfAdjoint

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    As Lubos Motte found out, you cannot explain a change by something that predicts a constant level, so any hereditary component of the propensity to gain weight can't be blamed for a new epidemic of obesity. That doesn't mean such a hereditary component doesn't exist, and indeed it has been shown to exist.
     
  15. Aug 29, 2006 #14
    Yes. You can eat 0 % fat yet still have fat end up on your thighs--has to do with carbohydrate metabolism
    No--but they could still be obese. There is a difference between being overweight and being obese. In fact, one can be obese yet not overweight, or overweight but not obese. Thus an obese person with genetic disposition can expend more calories, become less overweight, yet still maintain physiological state of obesity due to genetic inability to metabolize fat molecules.
     
  16. Aug 29, 2006 #15

    chroot

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    I mentioned nothing about fat versus carbohydrates, nor is it relevant. A person who is 100 lbs overweight has eaten a minimum of 100 lbs more food, over their lifetime, than needed. There can be no argument about this.

    You're saying the definition of "obesity" is a genetic one? You understand, I hope, that your definition disagrees with that of every dictionary in print.

    - Warren
     
  17. Aug 29, 2006 #16
    I think it's more saying that disposition towards eating, metabolism rate, and other factors which could be gene-determined increase the expression of the obesity phenotype. This is not to say that obesity is not affected by enviromental stimulus. Genetics 101 really. You can't really disagree with that.

    But as chroot said, in the end it is upto the person in question making a concious decision to eat the food and not burn it.
     
  18. Aug 30, 2006 #17
    When you are born, you have every fat cell in place. You gain no more fat cells in your life. The amount and placement of these cells is determened by genes. Thats why you see big bottoms and thighs on some, or big bellies on others.
    It is now pretty clear that obesity is not just a matter of excess weight, because fat cells do not merely store fat: They send out bioactive molecules with powerful effects throughout the body. If you have more fat cells, its easier to gain weight, and harder to loose it.

    So the statment "It really is in your genes!" is very correct. But we also know, it can be over come with lifestyle changes. You may just half to work a bit harder at it.
     
  19. Aug 30, 2006 #18

    chroot

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    If a person needs 2,000 calories for their basal metabolism, yet eats only 1,500 calories per day, they have a deficit of 500 calories per day. This translates to a weight loss of one pound of pure fat per week.

    I see no reason why "having more fat cells" could possibly invalidate this simple fact. Can you please explain how "having more fat cells" can allow one to escape the conservation of mass?

    I believe your "having more fat cells" mumbo-jumbo is just more fat-sympathizing propaganda, to help people marginalize personal accountability for weight. "It doesn't matter what I eat, I can't lose weight! You see, I'm above the fundamental laws of physics, because I have more fat cells!" :rolleyes:

    - Warren
     
  20. Aug 30, 2006 #19

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    Hardly --- cells don't increase in size as we grow, they increase in number --- feed the fat, they increase --- feed the lean, they increase.
     
  21. Aug 30, 2006 #20

    chroot

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    Actually, hypatia is correct about this -- fat cells really do grow and shrink as they store and release fat.

    Hypatia's just incorrect in saying that somehow the absolute number of fat cells in one's body makes losing weight more or less difficult. That's just pandering, and cannot be physically valid.

    - Warren
     
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