Obesity is most commonly diagnosed based on the body mass index (BMI). However, it is known that some subjects with normal BMI have increased metabolic and cardiovascular risk associated with excessive visceral fat deposit. These subjects are defined as metabolic obese normal weight or metabolically unhealthy normal weight.

Metabolic obese normal weight is particularly frequent among young people, and low physical activity level is indicated as its primary cause. Metabolic obese normal weight is very rarely recognised in clinical practice.

The aim of this manuscript is a discussion of this phenotype of obesity and its diagnostic criteria.