Definition of Obesity
A person is considered to be obese if he or she is more than 20 percent over their ideal weight. This is a medical condition in which excess body fat has accumulated to the extent that it may have an adverse effect on health, leading to reduced life expectancy and/or increased health problems.
Obesity has been more precisely defined by the National Institutes of Health (the NIH) as a body mass index (BMI) of 30 and above. The BMI is a key index that relating the body weight to height, it can be calculated by dividing a person's weight in kilograms by height in meters squared. It defines people as overweight (pre-obese) if their BMI is between 25 and 30 kg/m2, and obese when it is greater than 30 kg/m2.
BMI provides the useful population-level measure of overweight and obesity as it is the same for both sexes and for all ages of adults. However, it should be considered a rough guide because it may not correspond to the same degree of fatness in different individuals. Since the BMI describes the body weight relative to height, it correlates strongly (in adults) with the total body fat content. Some very muscular people may have a high BMI without undue health risks.
Overweight and obesity are linked to more deaths worldwide than underweight. 65% of the world's population live in countries where overweight and obesity kill more people than underweight, this happenned in all high-income and most middle-income countries. Obesity is often multifactorial, which are based on both genetic and behavioral factors. Accordingly, treatment of obesity usually requires more than just dietary changes. Exercise, counseling and support, and sometimes medication can supplement diet to help patients conquer weight problems.
Key facts
Obesity has been more precisely defined by the National Institutes of Health (the NIH) as a body mass index (BMI) of 30 and above. The BMI is a key index that relating the body weight to height, it can be calculated by dividing a person's weight in kilograms by height in meters squared. It defines people as overweight (pre-obese) if their BMI is between 25 and 30 kg/m2, and obese when it is greater than 30 kg/m2.
BMI provides the useful population-level measure of overweight and obesity as it is the same for both sexes and for all ages of adults. However, it should be considered a rough guide because it may not correspond to the same degree of fatness in different individuals. Since the BMI describes the body weight relative to height, it correlates strongly (in adults) with the total body fat content. Some very muscular people may have a high BMI without undue health risks.
Overweight and obesity are linked to more deaths worldwide than underweight. 65% of the world's population live in countries where overweight and obesity kill more people than underweight, this happenned in all high-income and most middle-income countries. Obesity is often multifactorial, which are based on both genetic and behavioral factors. Accordingly, treatment of obesity usually requires more than just dietary changes. Exercise, counseling and support, and sometimes medication can supplement diet to help patients conquer weight problems.
Key facts
- Worldwide obesity has more than doubled since 1980.
- In 2008, 1.5 billion adults, 20 and older, were overweight. Of these over 200 million men and nearly 300 million women were obese.
- 65% of the world's population live in countries where overweight and obesity kills more people than underweight.
- Nearly 43 million children under the age of five were overweight in 2010.
- Obesity is preventable.
