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Saturated FatThe genetic limits of obesity.

By William SaletanPosted Thursday, June 5, 2008, at 7:58 AM ET

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An overweight coupleGood news: Child obesity in the United States has stopped increasing. Government data analyzed in the Journal of the American Medical Association tell the story. According to a New York Times summary, "in 1980, 6.5 percent of children age 6 to 11 were obese, but by 1994 that number had climbed to 11.3 percent. By 2002, the number had jumped to 16.3 percent, but it has now appeared to stabilize around 17 percent."

Experts are jubilant. Here's the Washington Post:

"This lets us know that the epidemic is not an unstoppable epidemic and gives us hope our collective work can reverse it," said Risa Lavizzo-Mourey, president and chief executive of the Robert Wood Johnson Foundation, a private nonprofit group that helps fund anti-obesity programs. "It tells us that when we all work together—parents and schools, government, voluntary organizations, industry—we can make a difference."

The Associated Press reports similar excitement:

Dr. Reginald Washington, a children's heart specialist in Denver and member of an American Academy of Pediatrics obesity committee, said "the country should be congratulated" if the rates have in fact peaked. "There are a lot of people trying to do good things to try to stem the tide," Washington said. Some schools are providing better meals and increasing physical education, and Americans in general "are more aware of the importance of fruits and vegetables," he said.

But wait: There's a problem. The stabilization may not be due to remedial interventions. According to the Times and other papers,

One concern is that the lull could represent a natural plateau that would have occurred regardless of public health efforts. "It may be that we've reached some sort of saturation in terms of the proportion of the population who are genetically susceptible to obesity in this environment," Dr. Ogden [the study's lead author] said. "A more optimistic view is that some things are working."

Bummer, huh? All that work we've been doing to teach healthy eating and exercise habits—irrelevant? Is the leveling off in child obesity just a product of genetic exhaustion?

I sure hope so.

I don't mean to dismiss the importance of changing habits. We'll need every bit of those changes to drive obesity back down to 1980 levels. But when you hear talk of making the world a better place, don't underestimate how much worse things can get. Job number one is to halt the frightening increase in fat. And the strongest ally we could ask for in holding that line isn't effort or education. It's genetics.

If, at 17 percent, we've hit the "saturation" point for child obesity, we're extremely lucky. There's no historical basis for knowing where the saturation point is, since our species has never before lived in an environment so full of ease and abundance. The far more dangerous possibility is that the saturation point is higher. In fact, given that we evolved in conditions of scarcity, it's logical to suspect that the tendency to seek and store fat is nearly universal. As the Los Angeles Times observes, "the idea that childhood weights have simply topped out doesn't quite square ... [One expert] said the fact that 60% of U.S. adults were either overweight or obese suggested that children had plenty of room to grow."

Two years ago, when I was researching the global escalation of obesity, I came across the work of Barry Popkin, an epidemiologist who studies obesity and hunger at the University of North Carolina. He's the guy who laid out the theory of how progress has changed our causes of death. In the hunter-gatherer era, if we didn't find food, we died. In the agricultural era, if our crops perished, we died. In the industrial era, famine receded, but infectious diseases killed us. Now we've achieved such control over nature that we're dying not of starvation or infection, but of abundance.

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You want a really scary explanation for the plateau in child obesity? Part of it, according to Popkin, may be economic. "When economic times are difficult, we always slow things down on lots of things, like eating," he told the Post.

In other words, as the economy recovers and advances, so will obesity. And nobody knows where it'll end.

So let's stop "congratulating" ourselves for "trying to do good things" and "make a difference" in the fight against obesity. Let's pray that a force stronger than human will is behind the current stabilization. Doing good is less important than being well.

(For the latest Human Nature updates and blog items, bookmark humannature.us.com.)

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William Saletan is Slate's national correspondent and author of Bearing Right: How Conservatives Won the Abortion War.

Photograph of overweight people by Jeff J. Mitchell/Getty Images.

COMMENTS

Remarks from the Fray:

There are several studies showing that obesity is actually HIGHER in households that suffer periodic food scarcity. This makes sense in an environment where caloric density is inversely correlated with price. If you live in a food insecure [environment] it would make evolutionary sense for you to a) clean your plate when food is available and b) eat as cheaply as possible -thus consuming a diet rich in Mac and Cheese, Top Roman, the cheapest/fattiest cuts of meat, and the off brand version of frosted sugar bombs.

I think that it is more likely that if there is a plateau that it is because we have maxed out on those kids living in sedentary households. Despite the population level increase in obesity, there are large numbers of health conscious parents who exercise with their children and work to ensure that they eat nutritious meals.

--nancyh

(To reply, click here.)

The correlation between fat and economic problems would be fourfold:

Stress. Cortisol is not just some gimmick that they use to push bullshit "weight loss" products on cable... It really is something that your body will produce more of if you are under stress... and that will help your body put on fat and keep it. Worrying about finances tend to increase stress, which increases cortisol. While most kids aren't involved in the family finances, if Mom and Dad are stressed out, then the kid usually gets stressed as well.

Sleep. If you don't get enough sleep, you are fatigued, which means you have a lower metabolism! At the same time, your body will react by stimulating your cravings. So you'll crave high energy foods constantly, and have a lower metabolism all day. If Mom and Dad are constantly stressed about money, it's likely that one of them will work later or take odd jobs, and its very likely the stress level of the house could easily reduce the ability for young kids to sleep... So this is another factor.

Food quality! This, of course, is the biggest factor. There is a reason that the lower income quintiles have a MUCH higher instance of obesity than the higher income quintiles. The best things you can eat are fish, fat-free dairy, low-fat grilled chicken, raw nuts, some whole grains, and of course all the fresh veggies and fruit that you need to fill out your calorie profile... The CHEAP available foods are usually fried, high glycemic load starches, and fatty low-quality cuts of meat... with maybe some over-boiled canned veggies (yuck) to add green stuff that kids won't eat...

Gym membership... While technically not needed to maintain a reasonably healthy lifestyle, it is HARD to just force yourself to exercise for 1-2 hours a day just on your own... The gym has been a godsend for me, well worth the 40.00/month... but there are a lot of families that couldn't throw down another 40.00/month.

No, families getting poorer should worsen the obesity epidemic... unless we start subsidizing healthy living then economic concerns should reasonably worsen the problem.

--Tundrayeti

(To reply, click here.)

Is this [article's picture] really necessary?

Images like this one are presumably meant to provide visual interest and context to a story. The faces are usually edited out, and the pictures range from relatively neutral to film footage that follows obese individuals walking on the beach - clearly meant to provoke a negative response. Why do we need these images? Don't we all know what fat people look like? If we think it's okay to put pictures of random overweight individuals on the internet, does that imply that they somehow deserve public mockery - for maintaining a BMI that's too high?

Think about the other pictures you see embedded in the media. Some human interest features show local heroes or innocent participants - like a kid at his desk in a back-to-school story. These are neutral images of people who probably clip them out for their refrigerator. Most other news stories involve either actions by public figures or alleged criminals. Fat people walking down the street fall into neither category.

It's perfectly legal to take pictures of anyone in a public area, and to use the images in any non-libelous way. The faces can be shown if an editor chooses to do so, though few would risk it. But perfectly legal actions are often wrong, and exploitative. Unfortunately, overweight people already face enough discrimination in our society that it will take a movement before people even notice that images like these in the media are inherently exploitative and cater to our collective prejudice.

Plus, aren't there more interesting graphics that can be used to draw attention to a news piece? Or are the overweight enough of a spectacle to get the job done?

--usually just reading

(To reply, click here.)

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