A teen above the 95th percentile is considered overweight because 95 per cent of their age group have a smaller BMI. A teen below the 5th percentile is considered underweight.

• 如果青少年的体制指数超过第95个百分点,那么就是过重,因为这个年龄的95%25的体质指数都小于这个百分点。若低于第5个百分点则是偏轻。