As we move through different stages of life, our bodies change, and so does the interpretation of BMI.

Children and Adolescents

For children and teens (ages 2-19), BMI is calculated the same way but interpreted differently. It's compared to other children of the same age and sex using growth charts and percentiles.

Adults (20-65)

For most adults in this age range, the standard categories (18.5 - 24.9) apply. This is the period where BMI is most predictive of long-term health outcomes.

Older Adults (65+)

Interestingly, some research suggests that for older adults, a slightly higher BMI (between 25 and 27) might actually be protective against certain health issues like osteoporosis and frailty. Maintaining muscle mass becomes more critical than just focusing on the number on the scale.