Criteria

Body mass index (BMI) percentiles based on age and sex

The following classification may be used in children >2 years of age based on BMI percentiles for specific age and sex:[64]

  • Underweight: <5th percentile

  • Normal weight: 5th to 84th percentile

  • Overweight: 85th to 94th percentile

  • Obesity: ≥95th percentile.

Obesity is further classified as:[3][5][6][66]​​​

  • Class 1 (BMI ≥95th percentile)

  • Class 2 (BMI 120% to 139% of the 95th percentile, or an absolute BMI of ≥35 kg/m² to <40 kg/m², whichever is the lower for age and sex)

  • Class 3 (BMI ≥140% of the 95th percentile, or an absolute BMI ≥40 kg/m², whichever is the lower for age and sex).

For children aged <2 years, BMI normative values are not available. Weight-for-height values above the 95th percentile in this age group can be categorised as overweight.[7] The World Health Organization 2006 growth standard is recommended in many countries for children aged 0-5 years, and for children aged 0-2 years in the US. WHO: Child growth standards. Opens in new window

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