Body mass index (BMI) is a measure of body fat based on height and weight that applies to adult men and women.Although your BMI does not actually “measure” your percentage of body fat, it is a useful tool to estimate a healthy body weight based on your height. Due to its ease of measurement and calculation, it is the most widely used diagnostic indicator to identify a person’s optimal weight depending on his height. Your BMI “number” will inform you if you are underweight, of normal weight, overweight, or obese. However, due to the wide variety of body types, the distribution of muscle and bone mass, etc., it is not appropriate to use this as the only or final indication for diagnosis.BMI is not used for muscle builders, long distance athletes, and pregnant women, the elderly or young children. This is because BMI does not take into account whether the weight is carried as muscle or fat, just the number.Formula for BMI calculation:BMI = weight (kg)/height2 (m2) (Metric Units)Based on the BMI of a person, the health is determined as being Underweight, healthy, overweight and obese. According to the world health organization, a BMI of <18.5 is underweight, 18.5 to ≤ 23 is healthy, 24 to ≤25 is overweight or at risk of diabetes, 26 to ≤ 30 is moderately obese and at higher risk, ≥ 30 is severely obese.A person with diabetes can regulate his obesity levels with a regular monitoring of BMI. Maintaining the BMI assures longevity to the patient.