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"An extra 10 calories a day puts more weight onto an obese person than on a thinner one." It needs to be explained how he determined that this isn't related to

"An extra 10 calories a day puts more weight onto an obese person than on a thinner one." It needs to be explained how he determined that this isn't related to _why_ they are obese in the first place, i.e. whether these are purely correlational facts. It would be nice if the New York Times wasn't susceptible to elementary statistical fallacies like this but... well this is nutrition after all.

streptomycin 14y ago
An interview in the New York Times is not an academic research paper. In this context, it's reasonable for the interviewer to take the mathematician's word for it rather than hammering away at a pedantic detail that may or may not be relevant.
- Almaviva 14y ago
  This would be reasonable if people who ought to know better didn't commit this kind of elementary error constantly, particularly in nutrition. It is your attitude, that it's reasonable to publish a scientific article in a major publication without independent thought and fact checking, that I am challenging.
  - scott_s 14y ago
    it's reasonable to publish a scientific article in a major publication without independent thought and fact checking The person you are replying to did not say or imply that.
howeyc 14y ago
There was a documentary on HBO recently that stated this as well. What's going on is that someone who is obese needs less calories per day to maintain their weight than someone who is not obese. Something to do with metabolism rates slowing down when you are overweight. See "Weight of the nation."
- colomon 14y ago
  Except that's completely backwards to any "calories needed" calculation I've ever heard before. For instance, I just tried http://caloriecount.about.com/cc/calories-goal.php http://caloriecount.about.com/cc/calories-goal.php (after googling it out of the blue) with starting weights of 300 and 200, ten pounds to lose both ways, everything else the same. The calculator suggested the 200 pound guy needed to eat 500 calories a day fewer than the 300 pound guy did.
  - waterlesscloud 14y ago
    It's just a calculator on the internet, based on some simple formula. If experimental data says otherwise, the calculator is simply wrong.
    - drostie 14y ago
      While this is true, it is not particularly enlightening. The problem is that earlier a definite assertion was made that obese people burn fewer calories per day when staying at the same weight, and colomon was saying that this is known to be contradicted by certain experimental facts. It is known from experiment that basal metabolic rates are larger as your weight goes up. It's even consistent with a simple causal model. Obese people have larger bodies, which require more maintenance -- a larger supply of blood vessels and a heart working harder to fill them, more energy expended in getting up and going to the bathroom, et cetera. So it's kind of "no mystery." Now, it might still be the case that this documentary was correct -- for example, while basal rates might be higher for obese people, perhaps normal-weight people simply have an exercise routine which increases their metabolism in general. Something like that would be useful and would help colomon understand why the result is backwards. Unfortunately, I didn't see the documentary and therefore I don't know this particular reason, but the question is legitimate and is not well-dismissed simply by saying, "oh you know that crazy internet."
    - whatusername 14y ago
      So the Hans Benedict formula (which has been in use since 1919) is directly weight related. The Katch-McArdle and Cunningham try to be more specific and relate to the Lean Body Mass (LBM). However -- since LBM is reasonably correlated with overall weight -- then we can assume that (all else being equal) the fatter person has a higher BMR.
Wilduck 14y ago
Thanks for bringing this up, I'd really like some statistical awareness to show up in science reporting. > It needs to be explained how he determined that this isn't related to _why_ they are obese in the first place, i.e. whether these are purely correlational facts. I would settle for a simple statement that "An extra 10 calories a day puts more weight onto an obese person than on a thinner one," all else equal or controlling for other factors. So much of science is based off accepting statistical evidence, that it would be invaluable for science reporting to state, at least in laymans terms, the statistical veracity of results. In this case such a statement should be even easier since we're dealing with a theoretical model of obesity. Is there a coefficient for "current weight" that is independent of other factors?
byoung2 14y ago
It needs to be explained how he determined that this isn't related to _why_ they are obese in the first place I agree that more explanation is needed...the thinner person may be thin because she is more active, and the obese person may be obese because she is more sedentary. An extra 10 calories would seem more likely to put more weight on a sedentary person than an active one.
- glenra 14y ago
  The reverse claim has just as much explanatory power. That is to say: The active person may be active because she is more thin, and the sedentary person may be sedentary because she is more obese.
dbecker 14y ago
I've only flipped through this so far, which obviously isn't enough to fully grasp the argument. But you can find the researcher's reasoning explained in his slides at : http://sciencehouse.files.wordpress.com/2012/02/aaas122.pdf http://sciencehouse.files.wordpress.com/2012/02/aaas122.pdf

streptomycin 14y ago

An interview in the New York Times is not an academic research paper. In this context, it's reasonable for the interviewer to take the mathematician's word for it rather than hammering away at a pedantic detail that may or may not be relevant.

Almaviva 14y ago
This would be reasonable if people who ought to know better didn't commit this kind of elementary error constantly, particularly in nutrition. It is your attitude, that it's reasonable to publish a scientific article in a major publication without independent thought and fact checking, that I am challenging.
- scott_s 14y ago
  it's reasonable to publish a scientific article in a major publication without independent thought and fact checking The person you are replying to did not say or imply that.

howeyc 14y ago

There was a documentary on HBO recently that stated this as well. What's going on is that someone who is obese needs less calories per day to maintain their weight than someone who is not obese. Something to do with metabolism rates slowing down when you are overweight. See "Weight of the nation."

colomon 14y ago
Except that's completely backwards to any "calories needed" calculation I've ever heard before. For instance, I just tried http://caloriecount.about.com/cc/calories-goal.php http://caloriecount.about.com/cc/calories-goal.php (after googling it out of the blue) with starting weights of 300 and 200, ten pounds to lose both ways, everything else the same. The calculator suggested the 200 pound guy needed to eat 500 calories a day fewer than the 300 pound guy did.
- waterlesscloud 14y ago
  It's just a calculator on the internet, based on some simple formula. If experimental data says otherwise, the calculator is simply wrong.
  - drostie 14y ago
    While this is true, it is not particularly enlightening. The problem is that earlier a definite assertion was made that obese people burn fewer calories per day when staying at the same weight, and colomon was saying that this is known to be contradicted by certain experimental facts. It is known from experiment that basal metabolic rates are larger as your weight goes up. It's even consistent with a simple causal model. Obese people have larger bodies, which require more maintenance -- a larger supply of blood vessels and a heart working harder to fill them, more energy expended in getting up and going to the bathroom, et cetera. So it's kind of "no mystery." Now, it might still be the case that this documentary was correct -- for example, while basal rates might be higher for obese people, perhaps normal-weight people simply have an exercise routine which increases their metabolism in general. Something like that would be useful and would help colomon understand why the result is backwards. Unfortunately, I didn't see the documentary and therefore I don't know this particular reason, but the question is legitimate and is not well-dismissed simply by saying, "oh you know that crazy internet."
  - whatusername 14y ago
    So the Hans Benedict formula (which has been in use since 1919) is directly weight related. The Katch-McArdle and Cunningham try to be more specific and relate to the Lean Body Mass (LBM). However -- since LBM is reasonably correlated with overall weight -- then we can assume that (all else being equal) the fatter person has a higher BMR.

Wilduck 14y ago

Thanks for bringing this up, I'd really like some statistical awareness to show up in science reporting. > It needs to be explained how he determined that this isn't related to _why_ they are obese in the first place, i.e. whether these are purely correlational facts. I would settle for a simple statement that "An extra 10 calories a day puts more weight onto an obese person than on a thinner one," all else equal or controlling for other factors. So much of science is based off accepting statistical evidence, that it would be invaluable for science reporting to state, at least in laymans terms, the statistical veracity of results. In this case such a statement should be even easier since we're dealing with a theoretical model of obesity. Is there a coefficient for "current weight" that is independent of other factors?

byoung2 14y ago

It needs to be explained how he determined that this isn't related to _why_ they are obese in the first place I agree that more explanation is needed...the thinner person may be thin because she is more active, and the obese person may be obese because she is more sedentary. An extra 10 calories would seem more likely to put more weight on a sedentary person than an active one.

glenra 14y ago
The reverse claim has just as much explanatory power. That is to say: The active person may be active because she is more thin, and the sedentary person may be sedentary because she is more obese.

dbecker 14y ago

I've only flipped through this so far, which obviously isn't enough to fully grasp the argument. But you can find the researcher's reasoning explained in his slides at : http://sciencehouse.files.wordpress.com/2012/02/aaas122.pdf http://sciencehouse.files.wordpress.com/2012/02/aaas122.pdf