Mean Genes

San Diego Union Tribune


11-Sep-2000 Monday




Today, the hunter-gatherer orders a pizza



Left to our own devices -- or vices, as the case may be -- we would rather eat than exercise and sleep than sweat.

Call it the energy-conservation instinct, the path of least resistance, where the footprints of our hunter-gatherer heritage are permanently implanted in our DNA.

So the next time you declare your body a fat-free zone, honor tradition and allow a little margarine for error.

Just don't slather it on too generously.

Some of those genes you're carrying around like excess baggage were designed more for surviving in the wild, where the next meal was a rumor, than in an industrialized society where our needs are virtually at our fingertips.

Without a refrigerator at their disposal, those resourceful ancestors stored what we would consider leftovers as fat, the better for lean times ahead.

As Jay Phelan, a researcher in evolutionary genetics and aging, puts it: "Our genes haven't had a chance to catch up to the world we're living in, with all the extra food."

That may not be the source of obesity, eating disorders or sloth –  especially in a society where health advice is as abundant as exercise equipment -- but it's a likely contributor.

Phelan, a UCLA biology professor, collaborated with fellow scholar Terry Burnham in writing "Mean Genes," (Perseus Publishing), which examines, among other things, why we're sometimes more prone to use a remote control than self-control.

In a genetic context, survival of the fittest translates to survival of the hunter-gatherers who moved when they had to and ate whenever they could.

The irony is that extra food in the wild increased longevity. In our society, it limits it.

"But our ancestors were expending calories to get food and, too often, we don't," said Phelan, who has a doctorate in biology.

That genetic component, however valid, has been overcome by generations of health-conscious individuals who have learned not to trust their instincts even as they acknowledge them. In a sense, they've reinvented themselves.

For Phelan and Burnham, whose doctorate is in economics, willpower isn't enough. There has to be a worthy goal involved -- a means to an end that can neutralize what some have labeled our "laziness gene."

Burnham, who studied at San Diego State before earning his doctorate from Harvard, went without a car for a while, so he was forced to ride his bike.

He also discovered that team sports were a better exercise option than the gym.

"Teammates are counting on you," he said. "I don't think of it as a workout. I just go. Exercise is part of my transportation and part of my social life."

Burnham took a trip back in time in researching his book, studying wild chimpanzees in the rain forest of Uganda and visiting primitive societies where food is a luxury.

"I saw one black woman running in Uganda," he said. "As it turned out, she was from Switzerland. No Ugandans jog. There's no way they can understand an eating disorder like bulimia. They're problem is exactly the opposite – they're hungry all the time."

Phelan once tamed his mean genes on a long-distance flight by smearing a small packet of mayonnaise on the brownies provided on his airline meal. Instead of being tempted, he was repulsed.

Now he dreads the day when a Krispy Kreme doughnut shop (there are nearly 150 of them nationwide) could be within sniffing distance of his environment.

"Right now, the closest one is 18 or 19 miles away," he said. "But the company's doing so well, they're ready to expand."

And so are we if we give in to those primal instincts too often.