Friday, January 6, 2012

The Obesity Epidemic: When Biology and Culture Conspire Against Us

What We Eat or What We Are?

Tara Parker-Pope’s recent cover story in The New York Times Magazine, “The Fat Trap: Do You Have to be Superhuman to Lose Weight?” describes what is fast becoming canon: that modern culture has unmasked in our evolutionary biology a genetic propensity to defend against scarcity and starvation by retaining excess fat.

Research that documents weight plateaus for dieters, and biological differences between obese subjects and others is allowing us to assemble a picture of the human animal as metabolically hard-wired to conserve or regain weight -- especially after it has been reprogrammed by periods of obesity. Research also lends strong support to genetic differences in the degree to which individuals may be prone to obesity based on innate metabolism, food addictions, or other epigenetic factors.

Many frustrated dieters will find redemption in that thesis -- as, clearly, does Parker-Pope, whose article is unusually solipsistic for a card-carrying science writer. It is really a lamentation … which just goes to show how intractable and all-consuming this problem truly is for those of us who live in societies of plenty.

Dim Prospects for Cure

It turns out that when culture and biology team up, they have the potential to do great mischief together. Modern obesity and modern terrorism both demonstrate how aspects of our basic nature can be potentiated by forces of culture -- including both the Big Mac and the Internet -- to produce negative outcomes.

Under the broad heading of “lifestyle,” we see the simultaneous effects of many phenomena that all work to pack on the pounds: transportation and technology that keep us sedentary; an oversupply of cheap, addictive calories; and permissive attitudes concerning where, when, and how we eat. Among other factors, less often discussed but also quite relevant, are the impulse to use high-calorie food as compensation for social deprivations or economic inequities, and the peculiar elevation of food imagery in Western society to something very nearly pornographic. It turns out that the biochemistry of obesity is complex and still mysterious. Culture is too.

Unfortunately, we do not appear to be having much success manipulating biology right now, and future prospects seem no more promising. The pharmaceutical industry would love to see obesity addressed with a chronic therapy model -- and many patients probably would too -- but drugs have been remarkably unsuccessful in achieving safe, significant, and sustained weight loss, and the complexity of the problem (from a genetic or biochemical perspective) makes a magic bullet mechanism unlikely. In fact, it may be more plausible to look for ways to get dieters over the humps and hurdles intermittently than to medicate them chronically against the return of obesity.

Bariatric surgery is often offered up as a more effective alternative, and recent data suggest positive CV outcomes. But in a society where obesity is already commonplace, it seems reckless to endorse an approach that might make gastric bypass as ubiquitous as tonsillectomies used to be.

Fighting the Culture Wars

That leaves us with culture modification and behavior change -- an equally tall order but one with so many different levers to pull that the potential for meaningful effects might actually exceed the benefits of drug chemistry. The relative success of commercial programs like Weight Watchers suggests that dietary strategies may come closest to cracking the code when they parlay basic portion control, social reinforcement, and structured behavior in equal measure. This all passes for common sense, but in order for more of us to achieve greater mastery over our environment and our metabolism, we need some important things to happen:
  • As a society and as individuals, we have to acknowledge that, whatever the causes, obesity is a preventable illness, not a preordained destiny, and that it ultimately reflects an imbalance between calorie supply and demand.
  • We have to recognize that childhood obesity is exceptionally dangerous because, like certain kinds of drug exposure, it may reset biochemical mechanisms and create metabolic memories that are very hard to erase.
  • As a result, we need to take a much more aggressive approach to nutritional intervention in schools -- woefully difficult at a time when we struggle to teach children to read, much less to eat.
  • We have to give it even higher priority as a health goal and look to promote more frequent (often uncomfortable) conversations between physicians and their patients on the subject of weight -- not fewer.
  • Even acknowledging that the genetics of obesity are interesting and worthy of study, we need to dedicate adequate resources to studying what kinds of behavioral manipulations work best.
  • We need to direct an even greater amount of research toward nutrition and the way various foods tend to stoke or suppress the metabolism.
  • Armed with that kind of insight, we need to foster an approach that treats behavior modification programs as a reimbursable therapy, not just an option for motivated patients.

As to articles like Parker-Pope’s, people who struggle with weight should be treated compassionately and respectfully but it’s important not to spend too much time in the comforting arms of biological self-justification. We need to move on from there.

Updated Jan. 9, 2012

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