The article claims that by 2030 86% of Americans will be overweight. This is based purely on extrapolating the trends of the last 30 years. My own reading of the actual literature on the topic implies that a large minority of people are simply not weight-gainers. They have a lower appetite or have faster metabolisms or something other factor that protects them from weight gain. My understanding is that the rate of overweight has been increasing more slowly in recent years, as essentially all the people capable of becoming overweight already have.
Also, if obesity lowers life expectancy and causes serious health problems, I would expect people who are genetically more prone to obesity to have fewer descendants. I also suspect slimmer people probably reproduce more because 1. fitter men are more sexually successful and 2. pregnancy can be complicated by obesity. Since cheap, readily available fatty foods have only been available recently, the obese-prone have never been strongly selected against until now. Basically, fast food is kicking obese people out of the gene pool.
Also, if obesity lowers life expectancy and causes serious health problems, I would expect people who are genetically more prone to obesity to have fewer descendants.
This is a fun theory, but I don’t think it, y’know, works. Not being in the African savanna anymore, “pregnancy can be complicated by obesity” seems unlikely to have a powerful long-term effect. The effect is small enough in the aggregate population that it will easily be washed out.
Basically, yes, the obese would have slightly fewer children, ceteris paribus, but in dealing with complex social factors, ceteris is almost never paribus.
The attractiveness idea is fascinating, but probably wrong. People tend to anchor. My google-fu is not refined enough to find the study, but, in speed dating, the number of callbacks remains fairly constant even as group composition varies. If, on a given night, men are shorter or women are heavier, the opposite gender changes their standards accordingly. Traits that reduce sexual attractiveness are bad for the individual, holding else constant. But if those traits affect a large number of individuals, they’re largely irrelevant. Indeed, standards of attractiveness may even change a little; we’re already seeing some backlash against the idea that super-skinny is sexy.
The main thing that determines how many kids people have is… get ready… how many kids they want to have and/or how careful they are to avoid having more than this number. The strongest macroscopic determinant of this is culture/class, which happens to also correlate with obesity.
Granted, but that particular claim is not especially relevant to this conversation, nor does Wikipedia’s article on Kanazawa refute Jokela’s findings. My purpose for linking to that wasn’t to highlight the “women are getting more more beautiful” headline but simply to draw a connection from the claim that beautiful women reproduce more to the conclusion that obese women would therefore reproduce less. I don’t back this claim, because I haven’t read the paper, but unverified data is better than no data.
Having lived there and read up on problems with it, I find UK science reporting to be pretty awful, even compared to American science reporting.
The “birth defect” one is explained entirely in percentage change. Indeed, they are alarmed by the fact that deaths due to heart disease during pregnancy have doubled. They’ve doubled from .001% to .002% of all pregnancies. They don’t even mention natural frequencies for birth defects, but they all sound rather rare.
The women are getting more beautiful thing is similar—it sounds more like the product of a scientist with good PR than a scientist with good data (note the tone of the article, as if women should be celebrating. But none of them are getting any more attractive; they are thoroughly done evolving.). Also, attractiveness is positional, so if more people are less attractive, those people’s standards are likely to change to include one another. I can’t access the gated article or I’d break down their “objective measurements of beauty,” but BMI does not seem like a great proxy for beauty, particularly given the positional nature of the whole thing. And that researcher and his methodology have been criticized, for example here and here.
Height tends to correlate with both income and social class, which inversely correlate with obesity. Also note the article’s failure to say how big an effect there is. Also note that tall men don’t necessarily have more descendants, since taller women are less likely to have children, and (I’m pretty sure) taller men have taller daughters.
The amount of irrationality surrounding the obesity topic is really absurd. This following is a good example:
http://www.jhsph.edu/publichealthnews/press_releases/2008/wang_obesity_projections
The article claims that by 2030 86% of Americans will be overweight. This is based purely on extrapolating the trends of the last 30 years. My own reading of the actual literature on the topic implies that a large minority of people are simply not weight-gainers. They have a lower appetite or have faster metabolisms or something other factor that protects them from weight gain. My understanding is that the rate of overweight has been increasing more slowly in recent years, as essentially all the people capable of becoming overweight already have.
I’ve been preparing for this moment my entire life: a topical xkcd comic.
Huh? It happens all the time around here.
True, but not often enough!
Also, if obesity lowers life expectancy and causes serious health problems, I would expect people who are genetically more prone to obesity to have fewer descendants. I also suspect slimmer people probably reproduce more because 1. fitter men are more sexually successful and 2. pregnancy can be complicated by obesity. Since cheap, readily available fatty foods have only been available recently, the obese-prone have never been strongly selected against until now. Basically, fast food is kicking obese people out of the gene pool.
This is a fun theory, but I don’t think it, y’know, works. Not being in the African savanna anymore, “pregnancy can be complicated by obesity” seems unlikely to have a powerful long-term effect. The effect is small enough in the aggregate population that it will easily be washed out.
Basically, yes, the obese would have slightly fewer children, ceteris paribus, but in dealing with complex social factors, ceteris is almost never paribus.
The attractiveness idea is fascinating, but probably wrong. People tend to anchor. My google-fu is not refined enough to find the study, but, in speed dating, the number of callbacks remains fairly constant even as group composition varies. If, on a given night, men are shorter or women are heavier, the opposite gender changes their standards accordingly. Traits that reduce sexual attractiveness are bad for the individual, holding else constant. But if those traits affect a large number of individuals, they’re largely irrelevant. Indeed, standards of attractiveness may even change a little; we’re already seeing some backlash against the idea that super-skinny is sexy.
The main thing that determines how many kids people have is… get ready… how many kids they want to have and/or how careful they are to avoid having more than this number. The strongest macroscopic determinant of this is culture/class, which happens to also correlate with obesity.
Obese women ‘significantly more likely to have children with birth defects’ .
Women are getting more beautiful. “Beautiful women have more children than their plainer counterparts.”
Taller men… are more likely to father children. Tall men are less likely to be obese. Not a direct correlation though. Tall men also tend to earn more.
Just some results that may help shed more light on this. Without better data I don’t want to make any definitive statements, though.
I call BS. Wikipedia backs my play.
Granted, but that particular claim is not especially relevant to this conversation, nor does Wikipedia’s article on Kanazawa refute Jokela’s findings. My purpose for linking to that wasn’t to highlight the “women are getting more more beautiful” headline but simply to draw a connection from the claim that beautiful women reproduce more to the conclusion that obese women would therefore reproduce less. I don’t back this claim, because I haven’t read the paper, but unverified data is better than no data.
Having lived there and read up on problems with it, I find UK science reporting to be pretty awful, even compared to American science reporting.
The “birth defect” one is explained entirely in percentage change. Indeed, they are alarmed by the fact that deaths due to heart disease during pregnancy have doubled. They’ve doubled from .001% to .002% of all pregnancies. They don’t even mention natural frequencies for birth defects, but they all sound rather rare.
The women are getting more beautiful thing is similar—it sounds more like the product of a scientist with good PR than a scientist with good data (note the tone of the article, as if women should be celebrating. But none of them are getting any more attractive; they are thoroughly done evolving.). Also, attractiveness is positional, so if more people are less attractive, those people’s standards are likely to change to include one another. I can’t access the gated article or I’d break down their “objective measurements of beauty,” but BMI does not seem like a great proxy for beauty, particularly given the positional nature of the whole thing. And that researcher and his methodology have been criticized, for example here and here.
Height tends to correlate with both income and social class, which inversely correlate with obesity. Also note the article’s failure to say how big an effect there is. Also note that tall men don’t necessarily have more descendants, since taller women are less likely to have children, and (I’m pretty sure) taller men have taller daughters.