Obesity is an excess of body fat. But the question of what constitutes an excess has no clear answer. Some doctors classify a person as obese whose weight is 20% or more over the recommended weight for his or her height. But other doctors say standard height and weight charts are misleading. They maintain that the proportion of fat to muscle, measured by the skinfold "pinch" test, is a better measure of obesity. A person who is overweight, they point out, is not necessarily obese. A very muscular athlete, for example, might have very little body fat, but still might weigh more than the recommended weight for his or her height.
The causes of obesity are complex and not fully understood. While compulsive overeating certainly can lead to obesity, it is not clear that all obesity results from overindulging. Recent research increasingly points to biological, as well as psychological and environmental factors that influence obesity.
In the United States, people with low incomes are more likely to be obese than are the wealthy. Women are almost twice as likely as men to have the problem, but both men and women tend to gain weight as they age.
In those people whose obesity stems from compulsive eating, psychological factors seem to play a large role. Some studies suggest that obese people are much more likely than others to eat in response to stress, loneliness, or depression. As they are growing up, some people learn to associate food with love, acceptance, and a feeling of belonging. If they feel rejected and unhappy later in life, they may use food to comfort themselves.
Just as emotional pain can lead to obesity, obesity can lead to psychological scars. From childhood on, obese people are taunted and shunned. They may even face discrimination in school and on the job. The low self-esteem and sense of isolation that result may contribute to the person's eating disorder, setting up an endless cycle of overeating, gaining more weight, feeling even more worthless and isolated, then gorging again to console oneself.
People whose obesity endangers their health are said to be morbidly obese. Obesity is a risk factor in diabetes, high blood pressure, arteriosclerosis, angina pectoralis (chest pains due to inadequate blood flow to the heart), varicose veins, cirrhosis of the liver, and kidney disease. Obesity can cause complications during pregnancy and in surgical procedures. Obese people are about one and one half times more likely to have heart attacks than are other people. Overall, the death rate among people ages 20-64 is 50% higher for the obese than for people of normal weight.
Since compulsive eating patterns often have their beginnings in childhood, they are difficult to break. Some obese people get caught up in a cycle of binging and dieting—sometimes called yo-yo dieting—that never results in permanent weight loss. Research has shown that strict dieting itself may contribute to compulsive eating. Going without their favorite foods for long periods makes people feel deprived. They are more likely, then, to reward themselves by binging when they go off the diet. Other research shows that dieting slows the dieter's metabolism. When the person goes off the diet, he or she gains weight more easily.
The most successful programs for dealing with overeating teach people to eat more sensibly and to increase their physical activity to lose weight gradually without going on extreme diets. Support groups and therapy can help people deal with the psychological aspects of obesity.
Epstein, Rachel. Eating Habits and Disorders. New York: Chelsea House Publishers, 1990.
Matthews, John R. Eating Disorders. New York: Facts On File, 1991.
Porterfield, Kay Marie. Focus on Addictions. Santa Barbara: ABC-CLIO, 1992.
Berry, Kevin. "Anorexia? That's a Girls' Disease." Times Educational Supplement (April 16, 1999): D8.
Dansky, Bonnie S., Timothy D. Brewerton, and Dean G. Kilpatrick. "Comorbidity of Bulimia Nervosa and Alcohol Use Disorders: Results from the National Women's Study." The International Journal of Eating Disorders 27, no. 2 (March 1, 2000): 180.