Body Composition Tools in Young Children: A Spanner in the Works?

Worldwide, it was estimated that 39 million children under 5 years had weights above the healthy range in 2020,1 with upward trends in body mass index (BMI) observed across the life span.2,3 Although BMI is used to define overweight and obesity, many have criticized its use due to its inability to differentiate between fat and fat-free mass (FM and FFM, respectively). For example, some very lean athletes may be identified as having obesity using BMI, and the incidence of obesity may be over-represented in certain ethnicities due to greater levels of lean mass.