OBESITY

obesity and its psychological effects on the youth

Obesity and its psychological effects on the youth

Introduction

The prevalence of obesity has increased dramatically in the past three decades and is a serious concern in the United States. According to the National Center for Health Statistics in 1999, 61% of American adults were classified as overweight or obese. The prevalence is even higher among African Americans and Hispanics; nearly two thirds of African Americans are overweight or obese. In addition, the number of overweight children has increased dramatically. Between 1963 and 1980, childhood obesity increased by 98% among 6- to 11-year-olds. Prevalence in children is estimated to be 14% to 22% (Strauss, 2002). Excessive weight is associated with a number of health problems and ultimately mortality. Being overweight also brings with it a number of psychological and social consequences.

Defining Overweight And Obesity

When the energy a person consumes exceeds energy expenditure, weight gain results. One is considered to be obese when the body contains an excess of body fat (normally accounting for 25% of weight in women and 18% in men). Because body fat is difficult to measure, other indices have been developed to define obesity. Body mass index (BMI) is a commonly used metric in epidemiological studies for defining body weight and has a high correlation with direct measures of body fat. It is computed as weight in kilograms divided by height in meters squared. The World Health Organization and the National Heart, Lung, and Blood Institute have classified those with a BMI of < 18.5 kg/m2 to be underweight, 18.5 to 24.9 kg/m2 as healthy weight, 25 to 29.9 kg/m2 as overweight, and = 30 kg/m2 as obese. A BMI of 30 corresponds roughly to 40% above ideal weight.

BMI is frequently used as a guideline for establishing ideal weights because it has a strong relationship with mortality; at a BMI of 30, the risk of mortality increases approximately 30%. BMI does not take gender or frame size into account, is not a measurement of body fat, and does not assess for weight in specific areas of the body, but it is a useful heuristic in assessing body fat and calculating potential health risks.(Fairburn,2002)

Determinants

The determinants of body weight are not well understood, but there is increasing evidence that both genetics and environment play important roles.

Genetics

In families where one individual is obese, the likelihood that others will be obese as well doubles and is 7 to 8 times higher in families where there is extreme obesity (BMI > 45). In addition, obesity in children is more frequent in families where both parents are overweight. Genes are thought to explain 25% to 40% of the population variance in BMI. In studies of identical twins reared apart, genes account for 70% of the variance in BMI, whereas studies comparing adopted children and parents yield the lowest heritability levels (30% or less). Obesity-prone individuals may have increased appetite, diminished likelihood of being physically active, or metabolic differences in the way the body handles both ...