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A Mathematical Challenge to Obesity

nytimes.com

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Re: A Mathematical Challenge to Obesity

#31

Post by zerohp »

its_so_on wrote: post #23

I disagree with the article, and don't believe mathematics has the answer to obesity. However, if someone would like to start a diet-centered startup with me, I believe I have an insight that invalidates every diet book on the planet. Every diet book on the planet makes one very false assumption. Before we get to the assumption, let's review something uncontroversial: - You put on fat by eating more calories than you…

As someone who has lost a third of my body mass, I disagree with your premise: "Every single diet book makes the SINGULAR mistake of thinking that its reader is free to choose a strategy of consumption and of exercise." I am in complete control of my consumption and exercise. I found a strategy that works for me, and many others have found theirs. It wouldn't surprise me if there are 10 different diet books that work for 10 different people. On top of that there's probably 100 books that don't work for anyone.

Can you summarize your idea in a way that doesn't sound like a late night infomercial? The analogy of spending money and weight loss is flawed. The key to spending the money is not deciding that you want to do it. It's the action of writing the letter, signing the paper or calling your agent. Even when spending a great deal of money, this is an action that requires little willpower over time. You order someone to take care of it and it's no longer on your mind. In contrast, weight loss requires a constant input of will power over a long period of time. That's where people fail.

Re: A Mathematical Challenge to Obesity

#32

Post by drostie »

waterlesscloud wrote: post #25
colomon wrote: post #22

Earlier quoted context omitted.

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 (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.

It's just a calculator on the internet, based on some simple formula. If experimental data says otherwise, the calculator is simply wrong.

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."

Re: A Mathematical Challenge to Obesity

#33

Post by runhomequick »

colomon wrote: post #26
colomon wrote: post #22

Earlier quoted context omitted.

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 (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.

On consideration, it occurs to me that the original article may mean "extra over your maintenance calories". In other words, suppose the obese guy needs 3500 calories a day to maintain his weight, and the skinny guy needs 2000. Then I guess it might be true that if the obese guy eats 3510 calories a day, he will gain weight faster than the skinny guy eating 2010. That seems counter-intuitive but at least plausible.

For most people, extra calories will be split between being stored or being burned for energy by muscles. It's easy to fidget those 10 calories away if you aren't lethargic (which overeating for the obese is likely to cause).

Re: A Mathematical Challenge to Obesity

#34

Post by rprasad »

robomartin wrote: post #28

"And it’s something very simple, very obvious, something that few want to hear: The epidemic was caused by the overproduction of food in the United States." Overproduction? Does a factory intentionally produce more cars than it can sell? Probably not. How about a baker? Does a baker produce more cookies than she can sell? Not for long. Maybe a farmer? No. Not really. That is not an economically sustainable position t…

The government encourages overproduction of foodstuffs because it is better to have food and not need it (and consequently sell or store the unused food) then to need food and be without. That is, and always has been, the government's purpose in subsidizing agricultural production (even if that purpose is not shared by any of market participants).

Re: A Mathematical Challenge to Obesity

#35

Post by krupan »

potatolicious wrote: post #15
opiumden wrote: post #5

It's nice to see that people are developing new models and ways of thinking about weight loss but I wonder how effective this research is going to be. The conclusion of the article is the same old "eat less and eat healthier" which is fantastic advice ... and advice that a great many people don't bother to follow. As a culture we're eating ourselves to death while worrying that low probability events like terrorist a…

> "which is fantastic advice ... and advice that a great many people don't bother to follow" At least a large part of this is due to lack of education. For all the time we spend on math and science in public schools, we spend none of it on some basic principles like nutrition. I was rather obese in high school, and the (Canadian) government foot the bill for nutrition courses and consultations with a dietitian (this…

Actually, I was taught a lot about basic nutrition in school. Low fat was good, complex carbohydrates were good. 4 food groups. Now apparently that is all wrong?

Re: A Mathematical Challenge to Obesity

#36

Post by eugenejen »

mhartl wrote: post #13

You are an M.I.T.-trained mathematician and physicist. How did you come to work on obesity? ...I didn’t even know what a calorie was. I call bullshit.

Why do you say it as bullshit?

One important thing in higher education for math and physics is to be able to perform detail technical computations or modeling for phenomenons. In common high school and undergraduate physics class, it only requires students to be able to come up models with intuitions. But in graduate schools, you are trained to examine each step to make sure nothing is left out or based on assumptions that are wrong in your mind.

Therefore a lot of time you are not sure what something is until you re-examine all postulates that you learn when you are young.

Re: A Mathematical Challenge to Obesity

#37

Post by whatusername »

waterlesscloud wrote: post #25
colomon wrote: post #22

Earlier quoted context omitted.

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 (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.

It's just a calculator on the internet, based on some simple formula. If experimental data says otherwise, the calculator is simply wrong.

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.

Re: A Mathematical Challenge to Obesity

#38

Post by drostie »

opiumden wrote: post #5

It's nice to see that people are developing new models and ways of thinking about weight loss but I wonder how effective this research is going to be. The conclusion of the article is the same old "eat less and eat healthier" which is fantastic advice ... and advice that a great many people don't bother to follow. As a culture we're eating ourselves to death while worrying that low probability events like terrorist a…

It's slightly more nuanced than "eat less and eat healthier," because the article is pointing the finger at some general abundance. If you like, look at this researcher's perspective directly. It's not why is this person obese but rather why is everyone getting obese? So he's not going to recommend that the problem is at an individual level, but at an institutional level.

If you wanted to translate this advice for institutions to an advice for individuals, I think it would instead be something like, "pay attention." The hardest costs to see are often the steady everyday costs -- that morning coffee, the groceries, subscriptions, and so forth. The conclusions that "abundance is the problem" and "we're throwing away too much food" seems to suggest that it has sneaked in during the moments when people aren't paying attention; people now don't pay attention to the quantity of food they buy, so more of it gets bought, more gets eaten, more gets thrown away. Look at the things that come automatic, be less worried about single failures and more worried about the general patterns.

Re: A Mathematical Challenge to Obesity

#39

Post by wpietri »

colomon wrote: post #22
howeyc wrote: post #4

Earlier quoted context omitted.

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."

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 (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.

That's like saying, "Well, the retirement calculator said I could earn 6% on my portfolio, so it can't possibly turn out any other way."

Both sorts of calculators are based on broad averages and simplifying assumptions. It's not like the people at about.com went out and carefully measured intake, metabolism, and weight loss for 10,000 people, making sure to have enough data to get statistical resolution between a 300-pound builder and a 300-pound couch potato.

Re: A Mathematical Challenge to Obesity

#40

Post by waterlesscloud »

colomon wrote: post #26
colomon wrote: post #22

Earlier quoted context omitted.

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 (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.

On consideration, it occurs to me that the original article may mean "extra over your maintenance calories". In other words, suppose the obese guy needs 3500 calories a day to maintain his weight, and the skinny guy needs 2000. Then I guess it might be true that if the obese guy eats 3510 calories a day, he will gain weight faster than the skinny guy eating 2010. That seems counter-intuitive but at least plausible.

I suspect the actual meaning is that 10 extra pounds on the 200 pound guy takes more to maintain than 10 extra pounds on the 300 pound guy.

In other words, it's not a linear relationship.

That seems to make a lot of sense, actually.

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