WHAT IS THE DEFINITION of obesity?

overweight

Fatness intensified.
The blob
fat
when your BMI exceeds the limitations for your mass vs constitution index.
It's more than a certain % of body fat, but I'm not sure how much...
Obesity
The presence of excess body fat. The great prevalence of this condition, its severe consequences for physical and mental health, and the difficulty of treating it make the prevention of obesity a major public health priority.

Obesity is most often defined in terms of body weight relative to height, since both height and weight are easily measured. Obesity is considered to begin at a weight-for-height that is 20鈥?0% above desirable weight, with this desirable weight taken as the midpoint of ranges of weight associated with the greatest longevity in studies of life-insured individuals. In population surveys, obesity is defined as a body weight that meets or exceeds the 85th percentile of the Body Mass Index (BMI), an index of weight-for-height that correlates well with body fat content. See also Adipose tissue.

The prevalence of obesity increases with age, is higher in women than men, and is highest among the poor and minority groups. Obesity increases the likelihood of high blood cholesterol, high blood pressure, and diabetes, and therefore of the diseases for which such conditions are risk factors鈥攃oronary heart disease, stroke, and kidney disease. It also increases the likelihood of gallbladder disease and cancers of the breast and uterus. Thus, obesity increases overall mortality rates, and it does so in proportion to the degree and duration of overweight. Individuals who become obese at the earliest ages are at highest risk of premature mortality. Distribution of excess fat to the upper body rather than the lower body may also increase risk.

The causes of most cases of obesity are poorly understood. At the simplest level, obesity results from an excess of energy (caloric) intake over expenditure, but this statement does not explain why some individuals can eat as much as they like without gaining weight while others remain overweight despite constant dieting. Studies of genetically obese animals and those with damage to the part of the brain called the hypothalamus suggest that individuals may balance body weight around a 鈥渟etpoint鈥?that is maintained鈥攚ithout conscious control鈥攂y variations in metabolic rate in response to caloric intake. Variations in the prevalence of obesity among population groups suggest a genetic basis for the condition. The complexity of body-weight regulatory mechanisms suggests that obesity is not due to a single cause but, like other chronic diseases, is multifactorial in origin. Specific inherited differences that might influence setpoints include differences in nearly every anatomic, neurologic, and biochemical factor known to affect food intake and utilization, energy metabolism, and energy expenditure. See also Energy metabolism; Metabolic disorders.

Because the causes of obesity are incompletely understood, it is difficult to formulate effective treatment strategies. Studies suggest that programs combining diet and exercise help obese individuals lose more weight and maintain losses longer than either program does separately. See also Food; Nutrition.