Sunday, May 14, 2006

The Obesity Epidemic: Why Girth Rates Continue to Increase

The Obesity Epidemic: Why Girth Rates Continue to Increase
by Amy Scholten, MPH

The prevalence of overweight and obesity is increasing at an alarming rate all over the world, particularly in developed countries such as the U.S. In the October 9, 2002 issue of the Journal of the American Medical Association (JAMA), data from the Centers for Disease Control and Prevention (CDC) show that 31% of adults in the U.S. were obese in the year 2000 compared to 14.4% in 1980.

According to the CDC, about 15% of children and adolescents were overweight in 2000—triple what the proportion was in 1980.

Obesity is defined as having a body mass index (BMI) greater than or equal to 30. Overweight is defined as having a BMI of 25-29.9. BMI is a measure of body fat based on height and weight. It is calculated by dividing body weight in kilograms by height in meters squared.

Health Risks Associated with Obesity
In December 2001, the U.S. Surgeon General warned that obesity could soon kill more Americans than tobacco smoke. People who are obese are more likely to develop certain health conditions, including (but not limited to):

High blood pressure
High blood levels of cholesterol and triglycerides
Heart disease
Type 2 diabetes
Certain cancers:
Sleep apnea
Gallbladder disease
Urinary stress incontinence
Body pain
Gynecologic complications
Problems with labor and delivery

Some adverse health effects of obesity, such as type 2 diabetes and hypertension, are observed in children as well as adults.

What’s Behind the Epidemic?
Why such large and extensive increases in obesity? Data collected from around the world show that different environmental and cultural conditions contribute to obesity in urban and rural populations.

Obesity More Prevalent in Certain Groups

According to the Centers for Disease Control and Prevention, obesity tends to be more common in certain groups of people:

Women (33% vs 28% of men)
Non-Hispanic black women (50%)
Mexican-American women (40%)
Non-Hispanic black and Mexican-American adolescents ages 12-19 (24%)
Mexican-American children ages 6-11 (24%)
Non-Hispanic black children ages 6-11 (20%)
People with lower levels of education

Cultural and Environmental Factors

Experts believe that rising rates of obesity among children and adults may be attributed to a combination of the following:

Increasingly sedentary activities such as:
Watching TV
Using a computer
Driving long distances (for example, commuting)
Working long hours at sedentary jobs
Conveniences, such as drive-thru banking, which reduce physical activity
Lack of safe playgrounds
Increased consumption of soft drinks
Environmental factors that encourage overeating, such as:
Larger portion sizes in restaurants
Increased sizes of individual food items (such as soft drinks, candy bars, bagels)
Increased prevalence of vending machines
Greater number of food choices
Pervasive marketing of high calorie foods
Marketing strategies that encourage ordering larger serving sizes
Emotional overeating, triggered by increased stress
Childhood malnutrition and stunted growth
Repeated dieting
Greater acceptance of obesity in certain cultural groups

Girth Control in a Complex World
Although a number of complex cultural and environmental factors contribute to the obesity epidemic, in the majority of cases, the equation is basic: too many calories consumed and too few calories expended (too little activity) leads to obesity. In some cases, obesity is associated with underlying health conditions or medications and requires medical treatment. However, most people can achieve and maintain a healthful body weight by eating a more healthful diet and exercising regularly to burn off the calories they consume.

The following resources can provide you with more information:

Achieve and maintain a healthful weight

Eat a healthful diet

Start a regular exercise program


American Obesity Association

Centers for Disease Control and Prevention

American Dietetic Association


AAAS speakers report worldwide epidemic of obesity. American Association for the Advancement of Science website. Available at: Accessed January 17, 2003.

Flegal K, Carroll MD, Ogden CL. Prevalence and trends in obesity among US adults. JAMA. 2002;288:1723-1727.

Hill JO, Melanson EL. Overview of the determinants of overweight and obesity: current evidence and research issues. Medicine and Science in Sports and Exercise. 1999;31:515-521.

Ludwig DS, Peterson KE, Gortmaker SL. Relation between consumption of sugar sweetened drinks and childhood obesity: a prospective observational analysis. The Lancet. 2001;357:505-508.

Ogden CL, Flegal KM, Carroll MD, Johnson CL. Prevalence and trends in overweight among US children and adolescents, 1999-2000. JAMA. 2002;228:1728-1732.

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