6 Facts on Obesity

We've all heard warnings, yet many of us keep gaining weight. Sixty-five percent of American adults are overweight or obese, says the Centers for Disease Control and Prevention (CDC). People who are obese have an abnormally high and unhealthy proportion of body fat.

"Obesity is an epidemic right now. This is an important public health issue that is second only to tobacco," says William H. Dietz, M.D., Ph.D., director of the CDC Division of Nutrition and Physical Activity. In general, he says, "A man who is 6 feet and weighs over 220 pounds and a woman who is 5 foot 4 and weighs over 175 pounds are considered obese."

An adult who is overweight has a body mass index (BMI) of 25.0 to 29.9. An adult who is obese has a BMI of 30.0 or more. (To find your BMI, multiply your weight in pounds by 703. Divide that answer by your height in inches. Divide that answer by your height in inches, again. The resulting number is your BMI.)

You may know that obesity is linked to high blood pressure, diabetes, stroke, arthritis and harmful cholesterol. But scientists have five findings you may not know:

Finding 1: Obesity can raise some cancer risks

Researchers with the National Cancer Institute have determined that cancers of the breast (after menopause), colon, kidney, esophagus and lining of the uterus (endometrium) were associated with obesity and physical inactivity.

Finding 2: Obesity is tied to heart attacks in younger adults

Obesity has been linked to a rise in fatal heart attacks in young people. In people ages 15 to 34, the CDC notes, the death rate from heart attacks rose 32 percent among women and 10 percent among men during the 1990s.

"This increase was found to be related to obesity," says Dr. Dietz. Other factors, such as smoking and drug abuse, may also play a part. The CDC says young people can often avoid such deaths through good diet and exercise habits.

Finding 3: Obesity can ruin your day

For those who are obese, daily life itself is harder, studies show. Simple tasks like carrying groceries, walking up stairs, kneeling and stooping are more difficult for the obese. Research by the RAND Institute, the University of Wisconsin and the Dutch National Institute of Public Health and the Environment has shown that obese people fare worse in physical function, vitality and self-image. Sleep apnea, which is more prevalent among obese people, is often a cause of lethargy.

Obese people are also more likely to have a chronic disease or osteoarthritis. And doctors at the Glasgow Royal Infirmary in Scotland found obese women were more likely to miss work, see a doctor and feel down in the dumps than women who aren't obese.

Finding 4: Obesity speeds up girls' puberty

A study published in the journal Pediatrics found that girls who weigh too much tend to develop breast and pubic hair at age 8 or 9, earlier than their peers.

"Girls who show signs of early puberty are at risk for behavior and emotional problems. This is just one more consequence of being overweight," says study lead author Paul Kaplowitz, M.D., associate professor of pediatrics at Virginia Commonwealth University School of Medicine.

Finding 5: Obesity is a cause of diabetes in kids

Doctors believe rising childhood obesity helps explain a sharp increase in type 2 diabetes among kids.

"The best data demonstrate that type 2 diabetes, which was a rare disease in children and teenagers, is now much more common," Dr. Dietz says. In type 2 diabetes, the body can't make enough insulin or use it properly. Within the next 10 years, there will be more children with type 2 diabetes than with type 1. Among some minorities and in some age groups, the rate is even higher.

The American Academy of Pediatrics says most children with type 2 diabetes are obese. The disease usually turns up in middle to late puberty. Children who get little exercise, eat too much and have a family history of diabetes are at highest risk.

These researchers sound a joint theme: If you're obese, stop gaining weight and start losing. Doctors believe dropping 5 to 10 percent of your body weight can improve your health and decrease your risk of type 2 diabetes. Before you start a weight loss program, though, talk with your doctor.

"People care about their health," says Dr. Dietz, "so it is just a matter of time before they take the necessary steps to control their weight."

Finding 6: Obesity in middle age increases risk of dementia

People who are overweight or obese in midlife may have an increase risk of dementia in later life.  According to a study published in April 2005 in the British Medical Journal, people who were obese in their 40s were 75 percent more likely to develop dementia; for people who were overweight in their 40s, the risk rose by 35 percent.