Obesity Health Article

Obesity

Term describing a condition where the ratio of body fat to total body mass is higher than accepted norms.

Obesity is a relative term used to describe the condition where the ratio of body fat, which is measurable, to total body mass is higher than the accepted norm. {Obesity and overweight are often used interchangeably, but their technical definitions are different. Overweight refers to an excess of body weight that includes all tissues—fat, bone, and muscle. Obesity refers specifically to an excess of body fat.) Body fat is about 15% of total body mass for the normal adult male and about 20-25% for the normal adult female. A general rule of thumb is that an individual is probably obese when his or her weight exceeds the maximum weight on standardized height and weight charts by more than 20%. However, during childhood and adolescence, when the body is growing and developing, the proportion of body fat is slightly higher than for a mature adult. In addition, the proportion of body fat fluctuates during various stages of growth.

The percent of U.S. children who are overweight is estimated to be between 20-30%, but there is no firm definition of obesity for children and adolescents. The body mass index (BMI) and average weight-for-height charts provide general guidelines. Pediatricians and parents should evaluate an individual child's weight in the context of his stage of growth, level of physical activity, and general dietary habits. Richard P. Troiano, a researcher at the Centers for Disease Control and Prevention, encourages parents and physicians to observe children and adolescents in their environment over time, and cautions against making weight a disease. Adults should help children see the relationship between eating and exercise choices and weight.

Infancy through school age

Some babies are born obese, chiefly the result of diabetic mothers, obese mothers, or mothers with excessive pregnancy weight gains. The causes of neonatal obesity are therefore obvious; excessive insulin produced by the fetus itself in the first case and an excessive supply of transplacental nutrients in the latter cases. Neonatal obesity does not necessarily translate into childhood or later obesity, but there is an increased probability if the obese neonate is born into (or adopted into) an obese family.

Some babies actually become obese because of infant-care workers, grandmothers, or other parent-surrogates. Such care-giving individuals may simply value infant obesity ("a nice plump baby"), or they may use the bottle to quiet the infant, or to demonstrate their own competence as child-rearers. Because infants who are obese on their first birthday may be physically delayed in crawling and walking, they are therefore delayed in attaining the increased energy expenditure that ordinarily goes with toddler-stage activity.

Children of obese parents are more likely to become obese during childhood, and the presence of additional obese family members greatly increases that likelihood. Many studies have shown that the probability of childhood obesity rises with the number of obese family members (including both siblings and grandparents in the count). Though demonstrably familial, childhood and later obesity is not necessarily genetic, as evidenced by adoption studies. Normal weight children adopted into obese families are far more likely to become obese themselves.