Body mass index

Epidemiological studies indicate that one out of every three adults in the world is overweight. This abnormal accumulation of fat can be detrimental to health, although its consequences are not limited to the body, as it can influence mood and affect social life.

The body mass index (BMI), also known as the Quetelet index, is a simple indicator of the relationship between a person's weight and height that is often used to identify overweight and obesity in adults. It is defined as a person's weight in kilograms divided by the square of the person's height in meters (kg/m2). It is a simple criterion that classifies people as underweight, normal weight, overweight and obese. These BMI ranges are based on the effect that excess body fat has on disease and are well related to adiposity.

BMI is very easy to measure and calculate, making it the most widely used tool for correlating the risk of health problems with weight at the population level. Like any other measure, it is not perfect because it only depends on height and weight and does not take into account different levels of adiposity depending on age, physical activity levels and gender. For this reason, it can be expected to overestimate adiposity in some cases and underestimate it in others.

Approximately 39% of the world's population is overweight and obese, both of which are associated with increased risk of metabolic disease. In general, individuals with a higher BMI have a higher risk of cardiometabolic diseases such as type 2 diabetes, high blood pressure, stroke or even some types of cancers. This risk increases especially if you have significant fat deposits in the abdominal area.

The heritability of body mass index is thought to be high and the effect of different variants in genetic markers is thought to be stronger in women than in men. A meta-analysis of the genome-wide association study conducted on 800,000 individuals of European ancestry has identified 656 markers associated with body mass index values, including genes common to other traits, such as the FTO, MC4R or TMEM18 genes, related to the development of adipose tissue around organs.

Number of observed variants

13.5 million variants

Number of loci analyzed in the study

656 loci


Pulit S.L., Stoneman C., et al. Meta-analysis of genome-wide association studies for body fat distribution in 694 649 individuals of European ancestry. Human Molecular Genetics, 01 Jan 2019, 28(1):166-174

National Heart, Lung, and Blood Institute (NIH) [April 2022]

Word Health Organization (WHO) [March 2022]

The DNA test you were looking for