Is BMI the Best Tool to Determine Healthy Weight?

Posted 2025-11-25 10:07:56

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The WHO today recognizes the validity of the Body mass index (BMI) and has set the following ranges to determine the distinction between being thin and being overweight or obese.

Classification	BMI Range
Normal	18.5 and 24.9
Underweight	Under 18.5
Overweight	25 to 29.9
Obese	30.39.9

Calculate your BMI

To calculate your BMI, simply divide your weight—measured in kilograms—by your height squared—measured in meters

Limitations

Height

The mathematics of calculating BMI by dividing weight means that it returns too large a number for short people and too small a number for taller people: short people will be rated as being thinner and tall people fatter than they actually are.

Muscularity

Since muscle is heavier than fat, heavily muscled people, like athletes, weightlifters, boxers, etc. by virtue of their higher muscle mass, will be adjudged overweight or obese, despite having a lean midsection.

Ethnicity

Ethnic origin also affects BMI, which limits its use as a risk predictor for lifestyle diseases.

Sex

When calculating BMI it is important to consult the correct chart. BMI charts for adult males differs from BMI charts for females.

Age

BMI charts for children are not the same as for adults, as BMI changes substantially in children as the volume of fat carried varies with sex and age.

Pregnancy

BMI cannot, for obvious reasons, be used as a health indicator for pregnant women.

Waist to Height Ratio (WHtR)

WHtR is also one of the most accurate anthropometric indexes to screen for health risks. It factors in height, which is a proven predictor for hypertension and diabetes, and body fat percentage, which is an independent risk factor for heart disease.

Waist-to-Hip-Ratio (WHR)

WHR is a quick and easy way to check how much weight you carry around your middle. Used in conjunction with BMI it is a more accurate way to evaluate your weight and health.