What is the Body Mass Index?

Body mass index (BMI; weight in kilograms divided by height in meters squared) is a simple screening tool used to stratify obesity in adults (Table 1). It does not represent the individual amount of fat or health status, thought it has a relationship with mortality from all causes and is easy to use.

Body Mass Index (BMI) =   Body weight (kg) / Height (m²)

Obesity is defined by of BMI ≥ 30 kg/m² and overweight by a BMI between 25 and 29,9 kg/m². Being overweight doesn´t always mean increased amount of fat if it is at the expense of lean mass. In other hand, accumulation of intra-abdominal fat is highly correlated with metabolic and cardiovascular risk and can be measured by waist circumference (WC). Central or apple-shaped obesity (which confers higher risk) is defined as a WC of ≥94 cm in men and ≥80 cm in non-pregnant women. Lower cut-offs might be encountered according to the ethnic group (for example, Asian population are at risk of cardiovascular diseases with lower BMIs and lower WCs).