BMI is a useful screening tool but is not a direct measure of body fat. It provides a general indication of body fatness but does not account for factors like muscle mass, bone density, or fat distribution. For a more accurate assessment of body fat, other methods such as skinfold thickness measurements, bioelectrical impedance, or DEXA scans may be used.

Being overweight or obese increases the risk of numerous health conditions, including heart disease, stroke, high blood pressure, type 2 diabetes, certain cancers (such as breast, colon, and kidney cancer), sleep apnea, osteoarthritis, and fatty liver disease. Maintaining a healthy weight through a balanced diet and regular physical activity can help reduce these risks.

If your BMI indicates that you are underweight, overweight, or obese, making lifestyle changes can help improve your health. For those looking to lose weight, focus on consuming a balanced diet rich in fruits, vegetables, whole grains, and lean proteins, and engage in regular physical activity. If you are underweight, aim to increase your calorie intake with nutrient-dense foods and consider strength training to build muscle. Always consult with a healthcare professional before starting any new diet or exercise program.

The formula for calculating BMI is the same for children and adults, but the interpretation is different. For children and teens, BMI is age- and sex-specific and is often referred to as BMI-for-age. Healthcare providers use growth charts to compare a child's BMI to that of other children of the same age and sex. This helps determine if the child is underweight, at a healthy weight, overweight, or obese.