Body volume index

Obesity classification is a ranking of obesity, the medical condition in which excess body fat has accumulated to the extent that it has an adverse effect on health. The World Health Organization (WHO) classifies obesity by body mass index (BMI), which is closely related to both percentage body fat and total body fat. BMI is further evaluated in terms of fat distribution via the waist–hip ratio and total cardiovascular risk factors. In children, a healthy weight varies with age and sex, and is obesity determination is in relation to a historical normal group. Obesity classification is a ranking of obesity, the medical condition in which excess body fat has accumulated to the extent that it has an adverse effect on health. The World Health Organization (WHO) classifies obesity by body mass index (BMI), which is closely related to both percentage body fat and total body fat. BMI is further evaluated in terms of fat distribution via the waist–hip ratio and total cardiovascular risk factors. In children, a healthy weight varies with age and sex, and is obesity determination is in relation to a historical normal group. Obesity is a medical condition in which excess body fat has accumulated to the extent that it has an adverse effect on health. Relative weight and body mass index (BMI) are nearly identical and are reasonable estimates of body fatness as measured by percentage body fat. However, BMI does not account for the wide variation in body fat distribution, and may not correspond to the same degree of fatness or associated health risk in different individuals and populations. Other measurements of fat distribution include the waist–hip ratio and body fat percentage. Normal weight obesity is a condition of having normal body weight, but high body fat percentages with the same health risks of obesity. BMI can be used to predict the risk of metabolic abnormalities like diabetes. Body mass index or BMI is a simple and widely used method for estimating body fat mass. BMI was developed in the 19th century by the Belgian statistician and anthropometrist Adolphe Quetelet. BMI is an accurate reflection of body fat percentage in the majority of the adult population. However it is less accurate in people such as body builders and pregnant women. A formula combining BMI, age, and gender can be used to estimate a person's body fat percentage to an accuracy of 4%. An alternative method, body volume index (BVI), is being developed by Mayo Clinic in an effort to better take into account different body shapes. BVI measures body fat distribution and calculates the BVI number, based on these results. This BVI number is an indication of weight associated health risk. BMI is calculated by dividing the subject's mass by the square of his or her height, typically expressed either in metric or US 'Customary' units: The most commonly used definitions, established by the World Health Organization (WHO) in 1997 and published in 2000, provide the values listed in the table at right. Some modifications to the WHO definitions have been made by particular bodies. The surgical literature breaks down class III obesity into further categories, though the exact values are still disputed. As Asian populations develop negative health consequences at a lower BMI than western populations, some nations have redefined obesity. The Japanese have defined obesity as any BMI greater than 25 while China uses a BMI of greater than 28. The BMI-based definition is easy to use and it is particularly convenient for statistical purposes, since it only depends on two commonly measured quantities, one's height and weight. However, it ignores variations between individuals in amounts of lean body mass, particularly muscle mass. Individuals involved in heavy physical labor or sports may have high BMI values despite having little fat. For example, more than half of all NFL players are classified as 'obese' (BMI ≥ 30), and 1 in 4 are classified as 'extremely obese' (BMI ≥ 35), according to the BMI metric. However, their mean body fat percentage, 14%, is well within what's considered a healthy range. The preferred obesity metric in scholarly circles is the body fat percentage (BF%) - the ratio of the total weight of person's fat to his or her body weight, and BMI is viewed merely as a way to approximate BF%. Levels in excess of 32% for women and 25% for men are generally considered to indicate obesity. However, accurate measurement of body fat percentage is much more difficult than measurement of BMI. Several methods of varying accuracy and complexity exist.