Why are pre-pubescent children not accurately assessed using BMI?

The measurement of Body Mass Index (BMI) may not accurately reflect body fatness in pre-pubescent children primarily because they have not yet undergone the significant hormonal changes associated with puberty that influence fat distribution and storage. Before puberty, children's bodies are still developing, and their fat distribution patterns are not established in the same way as they will be later in their development. Thus, the hormonal influences that lead to characteristics such as increased fat mass, particularly in girls, and changes in body composition do not yet come into play, leading to a potential misinterpretation of BMI data for this age group. Consequently, BMI alone may not be a reliable indicator of whether a child is at a healthy weight or body fat level during prepubescence.