Interesting misinformation and confused misunderstanding being presented here as answers to a GQ.
Misinformation: obesity “is only affecting the most developed and affluent countries.” In fact obesity rates are increasing most rapidly in the developing world and more of the world’s obese are in the developing world than in the developed world.
The confused misunderstanding that if a condition is percieved as “self imposed” then it is not a disease has already been addressed.
The last one, that having local pockets without increasing rates of a condition somehow means there are no global implications, is just silly. Obesity is indeed a worldwide problem, with serious impact on poor countries as well as rich ones and, as that link states,
That said obesity has reached the point in much of the developed world where it might be more precise to label it as endemic than as an epidemic. And its global spread is rapidly reaching the point where golablly calling it a pandemic might be more precise as well.
No idea though if there is a GQ answer to the global population implications. As a fact based issue you’d need to consider any possible negative impact of obesity on fecundity and any offsetting impact of decreased malnutrition (especially during childhood) on fecundity rates in those regions with the highest population growth, such as India. Not sure if that data is available or where one would find it and it is likely way lost in the wash by other sociologic and economic factors.
In terms of birth rate, I don’t think obesity would have a significant effect. We have already reached Peak Child. The number of babies being born per year has been flat for the last couple of decades and there’s no indication that it will start going up again. As soon as Generation X reaches old age, global population will level out at 11 billion. If obesity manages to lower the fecundity rate by 1 or 2 percent, that’s smaller than the margin of error of our predictions anyway.
However, we will eventually face Peak Food. Obesity could accelerate Peak Food’s arrival date because obese people tend to consume more calories which means we use up our resources faster (such as artificial fertilizer). When the artificial fertilizer runs out and world food production starts to go down, the masses might get angry and the obese people.
This is the real issue. A middle-class couple typically cannot afford very many kids plus their lifestyle. You find many families topping out at one or two kids.
(Between my father and stepmother, they had 5 children with their previous spouses, none together. We five kids have had… five children total. Those children range from 45 to 20; so far, only 5 grandchildren, 4 from one grandson… by usual replacement rules, the generations should have gone - 4,8,16…)
The other problem is that as women’s lib has moved mother out of the home, several issues have arisen. First, a woman with a decent career has trouble finding the timing to have a child. Between “now is not a good time” and maternity leave not being good time to take away from a career, it’s difficult to find time. Then there’s child care expenses; very few have grandma sitting around waiting to help. The costs of the lifestyle toys too, have gone up. Where we used to have a radio, phonograph and TV, we have the full stereo system, big screen TVs, computers, iPads and cellphones, digital cameras… People used to car-pool, nowadays a family has two cars or more. I attribute a lot of the rise in the price of homes to the fact that there are two incomes to pay for the typical house instead of one. The average couple cannot afford a long interruption in that dual income.
As for obesity - based on what I see pushing baby carriages, I think GrumpyBunny has it right - there’s no shortage of mates for either gender.
Whether obesity impedes fertility - if the average woman is only planning to have one or two children, a 26% more difficult time getting pregnant means it may take two years instead of one out of a twenty-year window. (IIRC, fertility doctors will recommend testing after a year of trying has not produced results.) Lower libido? It doesn’t take that much. I think it was Freakonomics where the author mentioned studies about abortion, birth control and family planning - women usually have the number of children they plan to have. Birth control or the lack simply shifts the timing of that result. Families that only want one or two children, will stop there with more effective, permanent measures.
The socioeconomic factors being the major variable is certainly true but one fact to correct from Wesley’s post - it is not true that among the overweight and obese “the vast majority of them (85% I think) have BMIs of 25-35” - it is about 50/50 with marginally more obese (35 and over) than overweight. That “small minority” with BMI’s over 35 is about 14.5% (table 5). Those over 40 BMI is 6.4% and twice that among the subgroup of non-Hispanic Black.
It is the morbid obesity group, those over 40 or 50 BMI that have had the biggest increases in longer term trends.
Interestingly enough that of half of all overweight and obese being in the obese group begins in childhood. That’s table 3. “Obese” in kids is defined as a BMI in the historical 95%ile and “overweight” as 85 to 94.9%ile. Obviously historically 5% were obese and 10% overweight by definition. Applying those norms to the current population it is now (well 2011-2012 numbers) 16.9% “obese” and 14.9% “overweight.” But the increase has stopped and some sub-groups are actually improving.