The Ecology of Obesity
Winter, Metta, Human Ecology
Our Biology Conspires with Modern Environment to Make Us Fat
When you walk down the street in the United States today, the people you see who are of normal weight will be in the minority." With this stark fact, James O. Hill, professor of pediatrics and medicine and director of the Center for Human Nutrition at the University of Colorado Health Sciences Center, began his presentation of how it has come to be that almost seven out of every 10 Americans are overweight or obese. Hill gave the keynote talk, "Strategies to Address the Obesity Epidemic," at the Ecology of Obesity conference held at Cornell June 6 and 7, 2005.
The obesity epidemic is the result of a modern-day mismatch between our biology and our environment, which Hill says has created a perfect storm. On the one hand, biology works against our efforts to maintain a healthy weight, stemming from a time when, as hunter-gathers, humans needed to get enough food in a food-scarce environment. Doing so took constant physical effort.
"So our biology says: eat whenever food is available and rest whenever you can," Hill stated.
On the other hand, today's environment is radically different. Modern people no longer need to be constantly on the move foraging and hunting for food. Today Americans sit still while waiting at a drive-through window for a meal based on the cheapest ingredients industrialized agriculture has to offer: fat and sugar.
"We have engineered physical activity right out of our lives by the way we've built our communities," Hill said pointing to the universality of the automobile and suburbs designed to promote the movement of people in their cars rather than on their feet.
Hill called for an examination of the environment as a necessary first step in addressing the obesity epidemic. The built environment, with its prevalence of drive-up windows rather than sidewalks, is the most obvious. Hill also cited the commercial environment, which profits from selling large portions of high fat/high carbohydrate foods and devices such as high-definition TV, video games, and other modes of entertainment that promote inactivity.
He pointed out that progress and productivity often are inextricably linked to sitting at computer workstations. Company policies that lock stairwells in buildings deprive people of exercise. And many businesses do not require insurance companies to pay physicians for obesity prevention or treatment.
"Taking all of this together, it's clear that the environment produces obesity," Hill said. "Everywhere we export this environment around the world, it produces obesity there, too."
What's to be done? At present the average American gains one to two pounds a year. To get back to the 1980 obesity rate of 15 percent, Hill believes the focus must be on a 40- to 50-year, widespread public health strategy targeting both adults and children that promotes small behavior changes to prevent weight gain.
"The focus must be on prevention because prevention is the most efficient way to address obesity," Hill said. The combination of a modest decrease in caloric intake coupled with a modest increase in physical activity could result in the overall obesity rates going down with each successive generation, instead of going up as they are today.
To put this concept to work, Hill has become a collaborator with the grassroots non-profit organization America On the Move. This nationwide initiative, which is partnered with the YMCA, among other organizations, promotes an effective weight-control strategy of simultaneously eating 100 fewer calories a day while walking 2,000 more steps (the equivalent of one mile). He said it is essential to involve the private sector in changing the environment in ways that support these behaviors, such as rewarding fast-food restaurants for offering healthier menu items.
Individuals residing in communities participating in America On the Move are generating creative ideas to encourage physical activity. …