Vol 45, No.3
What causes obesity? Is it a personal choice that you have command over? Is it an acquired or inherited disease? Is it caused by environmental factors outside your control?
Experts, like Claude Bouchard, executive director of the Pennington Biomedical Research Center, Baton Rouge, La., have shown that the genetic hand you’re dealt has a profound impact on your weight and your ability to control it. Some people are pre-programmed to store calories; some burn more calories than others when they exercise.
It’s estimated that at least 40 percent of obesity can be attributed to genetics. And anywhere from 20 percent to 50 percent of the variation between people’s activity levels and response to exercise is inherited.
“We have to get away from this notion that it’s self-indulgence or gluttony,” says Dr. Eve Olson, director of St. Francis Medical and Surgical Weight Loss Center in Beech Grove, Ind., and author of “Obesity in the Workplace: A Case for Treatment,” (American Journal of Bariatric Medicine, 2003). “In general, the overweight don’t eat any more than their lean counterparts.”
Personal DNA aside, we’re all saddled with self-destructive tendencies. “The greatest law in human behavior is the law of least effort,” says David Levitsky, professor of Nutrition and Psychology at Cornell University. “We minimize our expenditure and maximize our take. We are stimulus-bound eaters; the more I put on your plate, the more you’ll eat.”
Experts round out the obesity equation by attributing 60 percent of the condition to external factors. “Genetics loads the gun, but environment pulls the trigger,” says Judith Stern, distinguished professor of nutritional and internal medicine at University of California, Davis. “Lifestyle choices—some imposed by society, others chosen by the individual—are major factors.”
One contributing factor is the convenience that’s been engineered into housing, transportation and office procedures. (See “Down with Convenience.”)
We’re burning 600 fewer calories per day in activity and eating 200-300 more calories in food, estimates Olson. “Basically, you have an 800 calorie excess that we didn’t have 40 years ago. That equates to 70 pounds per year. We have some mechanisms that retard that, but it’s still a scary number.”