Why Is There an Obesity Epidemic?

When one person puts on weight, there’s often a simple explanation: Too much time in front of the computer. An unhealthy attraction to pizza. An inherited tendency to pack on pounds. But what’s to blame when an entire country starts to bulge around the middle? One thing is certain: You can forget about simple answers.

The word “epidemic” is often overused, but there’s no better way to describe the explosion of

in America. According to the latest numbers from the Centers for Disease Control and Prevention (CDC), an astonishing 68 percent of American adults are overweight (meaning they have a body mass index, or BMI, of 25 or more) or obese. About 18 percent of children and adolescents are seriously overweight as well.

The outbreak has hit every part of the country, with the Midwest and the South leading the way.Somehow, we’ve created an ideal environment for gaining weight. How did we do it? Was it the invention of the Big Mac? The Internet? Supersize soft drinks? The remote control? It’s all of the above, and then some, says obesity expert James Hill, PhD, director of the Colorado Clinical Nutrition Research Unit at the University of Colorado.

Americans don’t get much exercise, but in fact, they need to exercise at least an hour a day to stay healthy, according to guidelines issued in September 2002 by the National Institute of Medicine. Members of a 21-person panel that issued the guidelines said they were concerned about the jump in obesity rates over the last few decades. According to the American Heart Association (AHA), all healthy adults should be getting at least 30 minutes of moderate intensity exercise five days a week. Modern conveniences keep people from the activities they need to stay in shape.

“Many people point to fast food, but Bill Gates is probably as much to blame as Ronald McDonald,” says Hill. In fact, just about every aspect of our society actively contributes to the epidemic, he says. According to Hill, “a bunch of little things” have dramatically tipped the scales. And in the case of the American waistline, little things can add up to something very large. Obesity has been directly linked to heart disease, high blood pressure, stroke, and type 2 diabetes and may set the stage for a host of other illnesses. In fact, American Cancer Society researchers estimate that obesity accounts for about one-third of all cancer deaths in this country.

Land of over-plenty

In the simplest terms, Americans as a whole are eating more calories than they burn. And why not? Food is more plentiful and more convenient than ever before. We don’t have to hunt it or scavenge it or harvest it. We just have to pull it out of the fridge, pick it up at one of 170,000 fast-food restaurants, or order it over the phone. “For most of human history, the real challenge was getting enough to eat,” Hill says. “Our bodies are well adapted for enduring famines, for getting the most out of each calorie. We are not built for abundance.”

Our history of hunting and scavenging also left us with a strong desire for fat, and the food industry has been more than willing to satisfy that desire. Today, Americans get about 35 percent of their calories from fat. Our love affair with fat has undoubtedly contributed to the obesity epidemic, but it’s far from the sole culprit, Hill says. In fact, the percentage of fat in our diet has hardly budged in the last decade, the period when the obesity crisis really took off.

It’s not an overload of fat that’s driving the epidemic — it’s an overload of just about everything, says Marion Nestle, PhD, MPH, Professor of Nutrition, Food Studies and Public Health at New York University. Everywhere, from coffee shops to restaurants, portion sizes have swelled beyond imagination. “People became used to large portions very quickly,” she says. “Regular sizes suddenly seemed skimpy.” According to the U.S. Department of Agriculture, the American diet has swelled by about 530 calories a day over the past 35 years, theoretically enough to add 53 pounds to every person every year.

Taking it easy

We could always burn off those calories with a little extra exercise, but most of us are headed in the opposite direction. “I see it in my own department,” Nestle says. “I write a lot of memos. I used to print them out and walk them down to the mailboxes. It wasn’t exactly Olympic exercise. But now I just send an e-mail to everyone. Most of my job involves sitting in front of a computer.”

Many of us can relate. At work, we point and click instead of sweat and toil. And when work is done, we have every opportunity to take it easy. Why walk to the post office when you can drive? Why walk around the mall when you can shop online? Why throw around a football when you can play NFL 2004 on your X-Box? In addition, many of our towns aren’t exactly conducive to walking. Who wants to stroll over to the nearest shopping center if you have to walk across a culvert and a freeway to get there?

We’re even keeping our children still. Physical education classes are disappearing across the country, and the ones that remain often aren’t very demanding, Hill says. And, of course, children are especially vulnerable to the pull of television and video games.

“This is probably the most sedentary generation of people in the history of the world,” former U.S. Surgeon General David Satcher says. Schools are also to blame for not providing healthier food, he says. They should encourage kids to eat low-fat, healthy food and decrease the number of vending machines located on school grounds, he says.

Making a move in the right direction, in 2006 the Alliance for a Healthier Generation brokered a deal with U.S. beverage distributors to stop selling soda at elementary and middle schools, and to only sell diet soda on high school campuses.

Still, put it all together and you have a crisis with deep, intertwined roots. No single factor caused the epidemic, and no single solution will slow it down. “Even if we got rid of every McDonald’s, Burger King, and Wendy’s in the country, we’d still have a big problem,” Hill says.

Need for community action

Unless the country takes the obesity epidemic more seriously, we’re in danger of losing many of the health gains in heart disease and other chronic health problems that we’ve made in recent decades, according to Satcher.

People who want to maintain a normal body weight should incorporate some form of exercise, according to the report issued by the Institute of Medicine. Adults and children should spend at least an hour a day doing moderately intense activities, such as walking, swimming, or bicycling.

On December 13, 2001, the federal government released a hard-hitting report entitled “The Surgeon General’s Call to Action to Prevent and Decrease Overweight and Obesity.” Among other things, the report urged schools to require physical education classes at all grade levels. (Currently only two states — Illinois and New York — require physical education each year from kindergarten through the 12th grade.)

The report also recommended turning off vending machines at schools during mealtimes, creating more opportunities for physical activity at worksites, offering extracurricular recreation programs, and creating safe and accessible recreation facilities for people of all ages. Finally, the report urged better education about the benefits of breastfeeding, since studies show that babies who are breastfed are less likely to grow into overweight adults.

In response to growing national concerns, members of Congress have sought to fund a series of community programs aimed at reducing obesity, including exercise programs in daycare centers and nursing homes, the construction of bike paths, and nutrition education programs in schools. Nutritionists have their own ideas of how to address the problem. For example, Peggy Agron, director of Project LEAN (Leaders Encouraging Activity and Nutrition) and a registered dietitian, feels that changing the food served in school cafeterias would benefit kids more than nutrition education programs. Still, experts say, all of these types of programs are a step in the right direction.

“Left unabated, overweight and obesity may soon cause as much preventable disease and death as cigarette smoking,” says Satcher. “People tend to think of overweight and obesity as strictly a personal matter, but there is much that communities can and should do to address these problems.”

Physician Toni Martin of Berkeley, California agrees. “Why don’t we insist that developers include walking paths in new housing developments?” she says. “Why don’t we mandate nutrition education in high school? Why don’t we ban junk food advertising for children the way we banned cigarette advertising? We could give prizes to kids who bring a piece of fruit or a vegetable in their lunch every day, or make vending machine manufacturers offer a minimum number of healthy choices for the privilege of installing their machines on campus. It doesn’t make sense to me to call a problem an epidemic and then attempt to solve it individual by individual.”

Despite the national increase in obesity, only 65 percent of obese adults have been told by their doctors or healthcare workers that they were overweight, according to the CDC.

That’s one reason why government health officials at the U.S. Preventive Services Task Force recommend that doctors assess patients to determine their BMI. If they’re obese, they should make weight loss counseling part of their talks.

What you can do

Meanwhile, it’s easy to get discouraged. Nestle, for one, sees little room for hope. Too many industries depend on keeping us overfed and inactive, “I don’t know how we’re going to win this war,” she says.

But Hill looks at it another way: Because a lot of small things helped start the epidemic, small changes in our lifestyles can help turn it around. Whether or not McDonald’s starts serving broccoli, he says, restaurants everywhere could scale back on their offerings of fat and calories. Likewise, few people have the willpower or desire to radically change their diets, but we can all find simple ways to cut calories. (For help, check out the United States Department of Agriculture’s Dietary Guidelines for Americans at http://www.health.gov/dietaryguidelines/.) We can’t dismantle the television or computer industries, but almost anybody can spare a half hour to 45 minutes every day for a brisk walk, he says.

Even small lifestyle changes require motivation, and that’s one thing that seems to be in short supply. “We haven’t done a good job communicating the urgency of the situation,” Hill says. “If people understood the seriousness of the epidemic, they would do what they needed to do.”


Flegal, KM et al. Prevalence and Trends in Obesity Among US Adults, 1999-2008 JAMA. 2010;303(3):235-241.

Interview with Marion Nestle.

Interview with James Hill.

Hill, J.O. and J.C. Peters. Environmental contributions to the obesity epidemic. Science, May 29, 1998. 280:1371-1374.

Nestle, M. and M.F. Jacobson. Halting the obesity epidemic: A public health policy approach. Public Health Reports, January/February 2000. 115:12-24.

Calle EE, et al. Overweight, obesity, and mortality from cancer in a prospectively studied cohort of U.S. adults. N Engl J Med 2003 Apr 24;348(17):1625-38

U.S. Preventive Services Task Force. Screening for Obesity in Adults: Recommendations and Rationale. Annals of Internal Medicine, 2 December 2003, Vol. 139 Issue 11. p. 930-932

Mokdad AH, et al. Actual Causes of Death in the United States, 2000. JAMA. 2004;291:1238-1245

Alliance for a Healthier Generation. Press Release: Centers for Disease Control and Prevention Statement on Action by U.S. Beverage Distributors to Restrict Soft Drink Marketing in Schools. May 2006. http://www.healthiergeneration.org/engine/renderpage.asp?pid=s030

U.S. Department of Agriculture. Agriculture Fact Book. 2001-2002. http://www.usda.gov/factbook/chapter2.htm

Office of Legislative Policy Analysis. http://olpa.od.nih.gov/legislation/108/pendinglegislation/impact.asp

Centers for Disease Control. Overweight. April 2006. http://www.cdc.gov/nchs/fastats/overwt.htm

American Cancer Society. Cancer Prevention and Early Detection Facts and Figures. 2007.

American Heart Association. Exercise and Fitness. 2007 October

Ogden C, et al. Obesity among adults in the United States No statistically significant change since 2003-2004. December 4, 2007. http://www.cdc.gov/nchs/data/databriefs/db01.pdf

© HealthDay

Follow us on Facebook