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Comment by gnoway | Hacker News Reader

The original WaPo article[1] is better IMO. It actually mentions that people on average are an inch taller than in 1960 before starting to pound the obesity drum.

[1] http://www.washingtonpost.com/blogs/wonkblog/wp/2015/06/12/l...

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But it also goes on to say that the main reason is we're eating less healthy food, more of it, and are less active, and that that inch only partially accounts for the increased weight.

About an inch, but actually less than an inch and even less so for women. So women are ~1% taller and 18.5% heavier. I don't think height is a factor.

You're assuming increased height only leads to a stretch in the z axis. If you linearly scaled someone up from 5'3 to 5'4 in every direction, the increase in volume would be 5%. So maybe not the main factor, but definitely a factor.

While you have a point, weight doesn't go like height cubed (you don't grow equally in all directions). I read an article a while ago (can't find it now) that looked at the exponent for various species. I think it was typically about 2.5 rather than 3. I suppose you could look at a BMI chart and back out the exponent that is assumed.

The actual formula for determining BMI only squares the height component.[0] Healthy humans should not even approach being cube shaped!

[0]https://en.wikipedia.org/wiki/Body_mass_index

To be fair, this article also mentions the increase in height.

Thank you. I read right over it.

I still think the original article (though shorter) is better.

This calculation is not exactly scientific, but : if U.S. women were an inch shorter then, that would make them 63 inches tall, instead of 64 inches (5'4). This equates to a 1.6% increase in height. If we assume that they have grown proportionally in all directions, we cube it, to get roughly a 5% increase in volume (which I will assume leads to a 5% increase in weight).

The increase in weight of women was a lot more than this, roughly 18%, so it seems to me this is not the important factor.

An inch in length doesn't weigh 26 pounds

From my less than scientific observations (past heavy experience with bodybuilding/weightlifting), at similar levels of leanness 15%, 1 inch = 5 lbs. A well known calculator kind of confirms that[0]. I could see less lean individuals being 10 lbs or greater at one inch but 26 sure does seem high.

[0] - http://www.weightrainer.net/bodypred.html

For instance, if you put in the values 69 inches tall, 7 inch wrists, 9 inch ankles and 15% BF (not super lean but not overweight), you get a maximum lean bodyweight (natural) of 210lbs (years and years of bodybuilding), but at 70 inches, with the same measurements, it shows 215lbs being the maximum lean weight.

Edit: Just to clarify, I'm certain that it's more of a percentage than a number and that it happens to be 5 lbs at around my height - a 4'll" woman might only differ 2-3 lbs at a similar build from a 5'0" woman.

Sure, what you described actually weights exactly 0 pounds.

But in general the volume of a sphere grows with the cube in regards to the radius, thus gaining an inch of height could add a lot of mass. How much depends on the object shape.

And no healthy person will gain 26 pounds when growing an inch. Get real man.

I'm already real. Start reading replies.

Up or out, what does it matter? It seems like overconsumption either way.

Isn't increased height generally taken as a sign of better nutrition?

Yes, diets low in proteins and certain vitamins/minerals (calcium, vitamins A and D) are associated with poorer physical development. This is why milk is fortified with A and D and we've bred rice (golden rice) that's high in these nutrients. That said nutrition probably only means the difference between 6' and 6'0.5", assuming you're not malnourished.

There's a huge grey area between "diets low in..." and "overconsumption".

And...? All things equal, greater caloric intake is associated with taller people.

That was my point in the first place.

Golden rice is genetically engineered. The pathway to synthesize vitamin A has been inserted.

I'm aware, genetically engineering plants is a type of breeding...

Yes. See the differences in the heights of the populations of the two Koreas over the past 50 or 60 years. Malnutrition in the north has resulted in a shorter population, while an abundance of food in the south has led to a taller population.

And? All that shows is that they ate less and were shorter as a result. Is that the conclusion?

Malnutrition is not the same as eating less. A healthy diet includes a variety of proteins, sugars, vitamins, minerals and other things. The North Korean diet has, for several generations now, been lacking in essential nutrients. The consequence is that their population has been shrinking (malnutrition during growing years means you don't grow).

You can over consume food and still be malnourished. See a friend of mine in college that subsisted off a diet largely consisting of pastas and cheese, sometimes fruit. He was incredibly unhealthy, though he obtained more than enough calories to maintain his weight (he was somewhat overweight at the time, but not extremely so). Once he improved his diet he had enough energy to actually start exercising again and resolved several ongoing medical issues he had at the time due to missing key nutrients in his diet.

I understand the malnutrition crisis in North Korea. Of course that situation is appalling. I'm just saying that malnutrition and height are not polar opposites on some spectrum of good health.

Up is probably more a result of better childhood nutrition and better knowledge of and avoidance of childhood (and maternal, prenatal) consumption that has adverse effects on development. People don't get tall from overeating.

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