Obesity

Over one-half of all Americans (about 97 million) are overweight or obese. If you are overweight or obese, carrying this extra weight puts you at risk for developing many diseases, especially heart disease, stroke, diabetes, and cancer. Losing this weight helps to prevent and control these diseases.

Obesity is a condition of excess body fat. It is the most common form of malnutrition in the Western world. It is important to note that no "diet or weight loss formula" works independently of an eating plan based on the Dietary Guidelines given by the mainstream nutrition and health institutes. So if you are obese throw away all those "special formulas", supplements, and pills, stop eating more calories than you need, become more physically active and adopt a healthy eating plan.

Severe overweight increases the risk for high blood cholesterol, high blood pressure, and diabetes and, hence, for diseases for which these conditions are risk factors (diabetes, coronary heart disease, high blood pressure, neurologic disorders, cancers, and kidney diseases). Obesity thus contributes to premature mortality. Of all obesity-related diseases, noninsulin dependent diabetes is most clearly and strongly associated with obesity.

Obesity is associated with too many adipose cells (hyperplastic obesity), adipose cells that are too large (hypertrophic obesity), or both. While changes in the size of adipose cells may occur at any age, the number of adult cells are fixed and determined by weight gain during certain periods of childhood development; fat cell numbers are established by late adolescence and, once established, does not decline.

Women generally have more subcutaneous fat than men, but men appear to suffer a greater cardiovascular risk from a given degree of fat than women. The distribution of body fat may be an indicator of this difference. Men accumulate more fat cells in the abdominal region than women (high waist-to-hip ratio). This distribution around the abdomen, referred to as upper body obesity, is associated with increased cardiovascular risk factors. Lower body obesity is more typical in women, who tend to accumulate fat in the hips, gluteal regions, and extremities, a distribution that does not appear to be associated with increased cardiovascular risk factors.

Regardless of gender, a high waist-to-hip ratio predicts an increased risk for cardiovascular disease and diabetes. The mortality ratio has been shown to increase with the degree of obesity, and with its duration.

Obesity is the net result of an excess of energy consumption over expenditure. Factors that must be considered as contributing to causation are: heredity, overeating, altered metabolism of adipose tissue, defective or decreased thermogenesis (the process by which calories are converted to heat), decreased physical activity without an appropriate reduction in food intake, and certain prescribed medications.

Overeating is clearly a prominent contributor to obesity. Feeding behaviour occurs in response to hunger and to appetite inducedby the presence of food. Satiety and the resulting cessation of eating occur in response to certain hormones, nervous impulses, and absorbed nutrients signalling the brain.

To loose weight, one must decrease caloric intake, increase caloric expenditure, or do both. Thus, the chief approaches to weight reduction involve behaviour change related to diet and exercise. Weight loss reduces health risks in the obese. Because obesity is a condition requiring continuous attention, any behaviour changes required to maintain weight loss must be life long.

With so many complex mechanisms causing a person to eat more than is needed, it is acceptably difficult to follow a strict recommended weight-loss program.

Key Recommendations

(From the Expert Panel on the Identification, Evaluation, and Treatment of Overweight and Obesity in Adults)

• Weight loss to lower elevated blood pressure in overweight and obese persons with high blood pressure.

• Weight loss to lower elevated levels of total cholesterol, LDL-cholesterol, and triglycerides, and to raise low levels of HDL-cholesterol in overweight and obese persons with dyslipidemia.

• Weight loss to lower elevated blood glucose levels in overweight and obese persons with type 2 diabetes.

• Use the BMI to assess overweight and obesity. Body weight alone can be used to follow weight loss, and to determine the effectiveness of therapy.

• The BMI to classify overweight and obesity and to estimate relative risk of disease compared to normal weight.

• The waist circumference should be used to assess abdominal fat content.

• The initial