Obesity

Abstract

Obesity is defined as an excess of body fat that is sufficient to affect health adversely. While the quantification of fat mass is usually only performed in the research setting, body mass index (weight in kg/height in metres2) is a useful surrogate marker for fat mass. Using the World Health Organization definition of a body mass index more than 30 kg/m2 to define obesity, 30% of Americans and 10–20% of Europeans are classified as obese, with the prevalence rising in many developing countries. As body mass index increases, so does the relative risk of type 2 diabetes, hypertension, and cardiovascular disease. As such, obesity is associated with disability, mortality, and substantial health costs. At an individual level, severe obesity can be associated with sleep disturbance and respiratory difficulties, joint and mobility disorders, as well as considerable social stigma which can affect quality of life, educational attainment, and employment opportunities.