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Comment by mamon | Hacker News Reader

Women has naturally higher body fat percentage, plus pregnancy and then menopause are both big hormonal shocks that induce weight gain, so this is hardly suprising.

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The study doesn't say they have more body fat. That we already know since woman are biologically prepared to do so.

The study says that more woman are obese: I.E.: Looking at healthy body fat in the two genders (where the healthy body fat levels for woman are already higher then men), more woman are above those levels.

Women may be more predisposed to put on fat more easily, because bearing and (even more) nursing a baby both add an enormous amount to a woman's energy needs. Even today, when food isn't scarce, many women lose their "baby weight" and more while nursing.

Secondly, with less testosterone, women put on and maintain muscle with less ease than men. Since muscle burns more resting calories than fat, women must restrict their calorie intake more strictly than men do - even at the same weight and activity level - if they want not to gain.

Ok, again: That is already accounted for when you talk about the healthy body fat levels for each gender. The study is about people that go above these levels.

I think the point he's trying to make is that while the natural level may vary between genders and be accounted for, they very likely didn't account for ease of weight gain.

Why should they account for the "ease of weight gain"? The study is about unhealthy fat levels, not if you easily gain more fat or not.

The study conclusion is simple: Obesity in men stabilized, obesity in woman is increasing.

They actually aren't adjusting for sex at all in their definition of obesity, it is just based on height and weight:

"BMI was calculated as weight in kilograms divided by height in meters squared, rounded to one decimal place. Obesity in adults was defined as a BMI of greater than or equal to 30."

And that is already actually favoring woman in the comparison since for the same BMI woman on average have more body fat and less muscle weight than men: http://www.cdc.gov/healthyweight/assessing/bmi/adult_bmi/ind...

All in all the study is about how these BMI measured obesity levels are stabilizing for men but increasing for woman and there is no rational way to go around the conclusion... so I don't get why people are so against the conclusions of the study.

> Women has naturally higher body fat percentage

Isn't that taken into account when drawing the line for what is considered to be obesity?

No it is not. Their criterion - and most everybody else's - is BMI>30. Which means that the only factor taken into account is height, nothing else. Not sex, not muscle mass, not age.

The reason why it still works for large populations is that very few people are freakishly short or tall, and pretty few are roided-up body builders.

Apparently, the limit for what is considered obesity for a 1.8 m tall person is 97 kg. I'd say the extra natural body fat of a woman doesn't make much difference.

Your suggestion does not appear to be valid for the UK.

"Data on overweight and obesity among adults are mainly from the Health Survey for England (HSE). Results for 2014 showed that 61.7% of adults were overweight or obese (65.3% of men and 58.1% of women). The prevalence of obesity is similar among men and women, but men are more likely to be overweight."

Projection from WHO:

"74% of men and 64% of women in UK to be overweight by 2030"

https://www.theguardian.com/society/2015/may/05/obesity-cris...

This is using BMI. BMI does not distinguish between body fat and muscle mass, causing it to be exceptionally inaccurate for men with a lot of muscle mass.

That's true, but if you take a walk around any random city in the UK you'll encounter far more fat people than muscly people. It's not even close. And I'm not talking about Mr-Universe-Era Arnie vs technically-but-not-terribly overweight, I mean just vaguely in shape vs visibly overweight

This may be anecdotal, but in my gym (Central London) most of the guys are skinny and most of the women are fat. I do notice the same in the street as well, so personally it's really hard to believe that there's actually more obese men in UK than women. Maybe city demographics is just different.

Yes, but if only one in ten of the men reported as overweight on BMI isn't overweight but muscular (and none of the women are), that explains almost all the difference between 65.3 and 58.1 percent.

The vast majority of people don't exercise anywhere near enough for this flaw in BMI to be a problem.

BMI is ridiculous because it also doesn't take into account body frame. There's a huge amount of difference between the amount of weight that someone with a 50" chest should carry and what someone with a 35" chest should carry.

I think according to BMI, I'm supposed to weigh like 180 pounds as a healthy weight. The lightest I have ever been was 210, after I spent an entire summer hiking 10-15 miles a day through the White Mountains, packing fifty pounds of tools, building trails and working with a crew that was half-vegan, so we subsisted on starvation rations.

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