Body Mass Index
Also called: BMI · Topic: Measuring Development: Income, HDI and Sustainability · NCERT: Class 10, Ch 1 "Development"; Class 10, Ch 5 "Consumer Rights"
Meaning
Body Mass Index (BMI) is a simple check of whether a person's weight suits their height. It is used to measure undernutrition and overweight.
BMI = weight (kg) ÷ height (m)²
For adults:
- below 18.5 = underweight
- 18.5–24.9 = normal
- 25 or above = overweight
- 30 or above = obese
Children are not judged by these adult cut-offs. They are checked against BMI-for-age charts.
Example
An adult weighing 60 kg with a height of 1.6 m has a BMI of 60 ÷ (1.6 × 1.6) = 60 ÷ 2.56 ≈ 23.4, which is normal. In an NCERT activity, a girl aged 14 years 8 months with a BMI of 15.2 is undernourished, while a boy aged 15 years 6 months with a BMI of 28 is overweight.
Don't confuse with
- Undernourishment (Prevalence of Undernourishment): This measures whether people's usual food intake gives them enough energy. BMI measures the body's weight against height.
Related concepts
- Infant Mortality Rate
- Maternal mortality rate
- Life expectancy
- Mortality rate
- Undernourishment
- Access to sanitation and drinking water