Obesity Health Article

Definition

Obesity is the condition of having an excessive accumulation of fat in the body, resulting in a body weight more than 20% above the average for height, age, sex, and body type, and in elevated risk of disability, illness, and death.

Description

The human body is composed of bone, muscle, specialized organ tissues, and fat. Together, all of these tissues comprise the total body mass, which is measured in pounds. Fat, or adipose tissue, is a combination of essential fat (an energy source for the normal physiologic function of cells and organs) and storage fat (a reserve supply of energy for future needs). When the amount of energy consumed as food exceeds the amount of energy expended in the normal maintenance of life processes and in physical activity, storage fat accumulates in excessive amounts. Essential fat is tucked in and around internal organs, and is an important building block of all cells in the body. Storage fat accumulates in the chest and abdomen, and, in much greater volume, under the skin.

Causes and symptoms

The human body was designed for life forty thousand years ago, when the ability to store energy in times of plenty meant the difference between life and death during famine. This protective mechanism is a source of trouble when food, in unlimited quantities, is readily available,. This is evident in the increasing prevalence of obesity in modern times, particularly in Western cultures. While obesity is just an exaggeration of a normal body, the storage of energy for future is properly classified as a health problem. This is because excessive amounts of storage fat may interfere with the normal physiology of the body. Obesity is directly related to the increasing prevalence of Type II diabetes in American society and for the appearance of Type II diabetes in children, previously a rarity. Because obesity promotes degenerative disease of joints and heart and blood vessels, it increases the need for some surgical procedures. At the same time, surgical complication rates are higher in obese patients. Obesity contributes to fatigue, high blood pressure, menstrual disorders, infertility, digestive complaints, low levels of physical fitness, and to the development of some cancers. The social costs of obesity that include decreased productivity, discrimination, depression, and low self-esteem, are less easily described and measured. Worldwide, obesity has reached epidemic proportions in the last thirty years, affecting both sexes and all ethnic, age, and socioeconomic groups. More than 50% of adults in the United States currently fall into overweight or obese classifications, and 22% of preschool children are classified as overweight. The increasing prevalence of obesity and diabetes in children and young adults heralds spiraling health care costs in the near future.

Because obesity reflects an imbalance between the amount of energy taken into the body in the form of food and the amount of energy expended in metabolism and physical activity, and because eating is an activity that involves choice and volition, obesity is classified by the Health Care Financing Administration (HCFA) as a "behavior" rather than as a disease. In recent years, following a pattern established in other behavioral problems such as alcoholism, researchers have attempted to establish a biologic basis for the development of obesity. They have succeeded in identifying many markers of the biochemical mechanisms that appear to be involved in feedback loops that control energy balance. However, much of the information is extrapolated from experimental work in rodents. Leptin, a hormone produced in fat cells is an example of such a marker. Leptin excited a great deal of hope as a potential treatment of obesity, but, as with many other laboratory discoveries, the hormone has proved far more complex and less easily understood in humans. Research to date indicates that obesity is the end product of numerous contributing factors, including genetics, hormonal influences, behavioral tendencies, medication effects, and the surrounding society. But the rapid and widespread increase in obesity in the last thirty years reflects changes in activity patterns and in eating habits, not a change in the human genetic pool or in physiology.