What is obesity?
Obesity is a condition in which the natural energy reserve of a mammal (such as a human), which is stored in fat, is expanded far beyond usual levels to the point where it is believed to pose a health risk. Obesity in wild animals is relatively rare, but it is common in domestic animals like barrows and household pets who may be castrated, spayed, overfed and underexercised.
Obesity is a concept that is being continually redefined. In humans, the current measurement of obesity is the body mass index (BMI).
A person with a BMI over 25 kg/m2 is considered overweight; a BMI over 30 kg/m2 is considered obese. The American Institute for Cancer Research considers a BMI between 18.5 and 25 to be an ideal target for a healthy individual (although several sources consider a person with a BMI of less than 20 to be underweight). The BMI was created in the 19th century by the Belgian statistician Adolphe Quetelet, and remained largely intact until June 1998 when the BMI was revised downward. This had the remarkable effect of changing some people's status from "ideal" weight to "overweight" in one day!
The BMI has been subject to fundamental criticism, as it ignores fat distribution in the body, and the fat/muscle proportion in total body weight. This means that a very fit athete with little fat but highly developed, and therefore heavy, muscles could be classified as obese. For instance according to the BMI system Brad Pitt is overweight while Russell Crowe is obese. Many researchers therefore hold that a high "waist-hip ratio" is the best indicator of metabolic disturbance, as visceral fat is more prone to cause insulin resistance.
Like the weight-to-height table, BMI does not show the difference between excess fat and muscle. BMI, however, is closely associated with measures of body fat. It also predicts the development of health problems related to excess weight. For these reasons, BMI is widely used by health care providers.
More information on obesity
What is obesity? - Obesity is a condition in which the natural energy reserve of a mammal. In humans, the current measurement of obesity is the body mass index (BMI).
What is morbid obesity? - Morbid obesity is clinically severe obesity or extreme obesity.
What is central obesity? - Central obesity (or 'apple-shaped' or 'masculine' obesity), is when the main deposits of body fat are localised around the abdomen and the upper body.
What is the body mass index (BMI)? - The body mass index (BMI) is a mathematical formula that uses your weight and height information to calculate your body mass.
What causes obesity? - Genetic, environmental, psychological, and other factors may all play a role in the development of obesity.
What're health risks associated with obesity? - Obesity has been linked to several serious medical conditions including: insulin resistance, heart disease and stroke, high blood pressure, type 2 (adult-onset) diabetes, cancer, gallbladder disease and gallstones.
How obesity is measured? - A number of tools are available to measure obesity. Most are based on height and weight ratios, body size and shape, and percent body fat.
How common is obesity? - Most health professionals say that obesity is an epidemic. Obesity in the adult population has doubled since 1980.
What's the treatment of obesity? - The mainstay of treatment for obesity is an energy-limited diet and increased exercise.
What's the dietary therapy for treatment of obesity? - Dietary therapy involves instruction on how to adjust a diet to reduce the number of calories eaten. Reducing calories moderately is essential to achieve a slow but steady weight loss, which is also important for maintenance of weight loss.
What's the exercise therapy (physical activity) for obesity treatment? - The primary goal of this therapy is to move sedentary people into an active category (even if it is moderate levels of intensity) and to move moderate level individuals into more vigorous levels.
What's the behavior therapy (physical activity) for obesity treatment? - Behavior therapy involves changing diet and physical activity patterns and habits to new behaviors that promote weight loss.
What about the drug therapy for obesity treatment? - Drug therapy may be used for weight loss and weight maintenance. Patients should be regularly assessed to determine the effect and continuing safety of a drug.
What about obesity surgery? - Obesity surgery is used to modify the stomach and or intestines to reduce the amount of food that can be eaten.
What's childhood obesity? - Obesity in children and adolescents is a serious issue with many health and social consequences that often continue into adulthood.