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Dr. Clif Cleaveland

Part 1 of 2

A growing epidemic of obesity in Tennessee and surrounding states will jeopardize the health of hundreds of thousands of adults and children and pile up unsustainable health-care costs.

Weight is assessed by the Body Mass Index, a calculation based on weight and height (use the BMI calculators for adults, children and teens at Obesity is defined as a BMI equal to or greater than 30. Severe obesity is diagnosed when the BMI is 40 or above.

Tennessee leads the nation in obesity for ages 10 to 17 years at 38 percent. Mississippi (37 percent), Alabama (35 percent) and Arkansas (34 percent) are close behind. Healthier states boast children obesity rates in the high teens. The overwhelming majority of obese children will become obese adults.

The incidence of adult obesity in these Southern states ranges from 37 to 39 percent. In healthier states the incidence is 22 to 24 percent.

The statistics for childhood and adult obesity have worsened for decades. Left unchecked, the incidence of obesity will soon exceed 40 percent for all ages in our region.

Consequences of obesity

Weight excess is a major risk factor for Type 2 diabetes. Fatty tissue is resistant to the effects of insulin. Production of the hormone can be increased in the presence of obesity for a time but ultimately begins to fail, leading to elevated blood glucose levels.

Previously tagged as "adult-onset" diabetes, the illness is now seen in obese children. Diabetes increases the concentration of triglycerides within the blood, which contributes to atherosclerosis — narrowing of arteries due to fatty deposits. Progressive damage to vision, kidney function and nerves results from uncontrolled diabetes.

Obesity is a contributing factor to high blood pressure.

The metabolic syndrome is a cluster of abnormalities that includes abdominal obesity, elevated blood glucose, high blood pressure, elevation of triglycerides and reduction of HDL ("good") cholesterol. Evidence for increased inflammation within the body has been linked to the metabolic syndrome.

Fatty liver results from the deposit of fat droplets within the organ. As fatty deposits accumulate, liver function progressively fails, resulting in cirrhosis — end-stage scarring. Liver transplant may be the only recourse at this point.

Obstructive sleep apnea is four times likelier in an obese person. Fatty tissue collects around the airways, restricting flow into the lungs.

The incidence of cancers of the esophagus, stomach, kidney and liver is increased by weight excess. Endometrial cancer and breast cancer in women who are post-menopause are increased. Cancer-causing chemicals that are fat-soluble accumulate in fatty tissue.

Visceral fat, which accumulates within the abdominal cavity in obese persons, produces hormones and other chemicals that may endanger health. Leptin acts to suppress hunger; however, as weight continues to increase, the response to leptin diminishes. Two substances related to inflammation are produced by visceral fat. This may explain some of the inflammatory changes noted in atherosclerosis of coronary arteries. The significance of other visceral fat products is unclear.

Consider the potential, cumulative effect if all of these abnormalities affected one overweight individual. He would be at increased risk for stroke, heart attack, kidney failure, loss of limbs from damaged nerves and blocked arteries, eye damage and cancer.

Sustained weight loss through diet can reverse these obesity-related changes up to a point. Surgical procedures, such as gastric-banding or bypass, can lead to significant weight loss in severe obesity. Organ damage may be irreversible.

Obesity poses individual and wider, social challenges to health.

Next week: How can we control the epidemic of obesity?

Clif Cleaveland, M.D., is a retired internist and former president of the American College of Physicians. Email him at