Body weight

Although many people prefer the less-ambiguous term body mass, the term body weight is overwhelmingly used in daily English speech and in biological and medical science contexts to describe the mass of an organism's body.

Weight, in the context of human body weight measurements in the medical sciences and in sports is a measurement of mass, and is thus expressed in units of mass, such as kilograms (kg) or pounds (lb). In Britain and Ireland, the unit stone (equivalent to 14 lb or 6.35 kg) is commonly used as well.

A quantity called body mass index (BMI) is often used to express weight relative to height. This is determined by dividing the weight of a person in kilograms by the square of the height in meters.

Health issues involving human weight

 * normal and abnormal growth and development
 * the physiological and hormonal control of ingestion and digestion
 * hunger and other motivations to eat
 * problems in regulating body weight, often resulting in obesity
 * eating disorders such as anorexia nervosa and bulimia nervosa
 * effects of disease, often resulting in cachexia

Non-health related issues involving human weight

 * leveling the playing field in various sports such as boxing, wrestling, and judo by classifying participants according to their weight
 * issues regarding seat sizing and weight limitations on airplanes and other forms of transport

The average weight for all ages, sex and races is rising at an increasing rate in the United States. Adult men and women are roughly an inch (2.5 cm) taller than they were in 1960, but are nearly 30 pounds (14 kg) heavier on average as well. The average weight for men aged 20-74 years rose dramatically from 166.3 pounds (75.4 kg) in 1960 to 191 pounds (86.6 kg) in 2002, while the average weight for women the same age increased from 140 pounds (63.5 kg) in 1960 to 164.3 pounds (74.5 kg) in 2002 Obesity is now often called an epidemic of global proportions.