Body Mass Index (BMI)
BMI is a simple mathematical calculation to estimate body fat. It is calculated by using person’s height and weight. BMI is commonly used to determine whether someone is overweight or fall within the healthy weight range.
Body weight represents the total weight of bones, muscles, fats, organs and fluids (blood, water etc.)
Too much body fat is associated with many long-term illnesses such as diabetes, heart disease, stroke, cancer, osteoarthritis and ageing. BMI gives good indication about the body fat and risk of developing chronic illnesses later in life.
It is also recommended to use the waist measurement with BMI to estimate body fat. There are different formulas to calculate BMI, based on the units of height (feet, cm) and weight (Kg, Ibs).
BMI has some limitations, it may not be accurate, such as it can result in over-estimation of body fat for athletes or young people who may have more muscle mass than fat. Similarly, it can under-estimate BMI of elderly person who may have less muscle mass.
A same BMI of two individuals may have different amount of fat in their bodies. In addition, interpretation of BMI and body fatness vary slightly for children and women.
However, for most people BMI is quite an accurate indicator to estimate body fat.
- A BMI below 18.5 is considered underweight
- A BMI range from 18.5 – 24.9 is considered normal (Green Zone)
- BMI of above 25 to 29.9 is considered overweight (Yellow Zone). These people have more body fat compare to overall body mass.
- BMI of over 30 is considered as obese (Red Zone)
Overweight and Obese people should bring balance in energy intake (food intake) and energy output (working out- physical exercise) - reduce calories intake and increase physical activity.
Obese people, in addition to energy balance may require some medications as per doctor’ instructions.
For simplicity, below table can give the BMI estimates.