Fatness

Fatness is the condition of having more body fat than typical for a person’s age or sex. In biology, adipose tissue stores energy, cushions and insulates the body, and secretes signaling molecules. Fatness is often described as adiposity, the amount of fat relative to total body mass, and it varies with age, sex, genetics, and environment. Adipose tissue includes white fat, which stores energy, and brown fat, which can generate heat. Excess fatness occurs when energy intake exceeds expenditure over time.

Measurement of fatness uses several methods. Body mass index (BMI) is simple and widely used but does not distinguish fat from lean tissue or its distribution. Other measures include waist circumference and waist-to-hip ratio to assess central fat, and techniques such as bioelectrical impedance, dual-energy X-ray absorptiometry (DXA), or imaging to estimate fat mass. Fat distribution, especially visceral fat, is linked to higher metabolic risk. Differences in fatness exist across sexes and ethnic groups.

Health effects of fatness are complex. Higher adiposity is associated with increased risk of cardiovascular disease, type 2 diabetes, and some cancers, particularly with central fat. Yet health status varies with fat distribution and metabolic function. Some individuals with higher fatness maintain favorable metabolic profiles, while others with normal weight have risk factors. Adipose tissue also secretes hormones such as leptin and adiponectin that influence metabolism.

Social and policy aspects include stigma and public health efforts to promote healthy lifestyles rather than focusing solely on weight. Programs emphasize nutrition, physical activity, and medical guidance, while acknowledging genetic, environmental, and socioeconomic influences on body size and health.