Body Mass Index (BMI) is a formula that uses height and weight to determine whether a man or woman is the appropriate weight.
Underweight BMI < 18.5
Normal weight BMI 18.5 to 24.9
Overweight BMI 25 to 29.9
Obese BMI 30 to 39.9
Extremely Obese BMI 40 or greater
BMI is a widely used formula but according to a study published this month in the British Journal of Nutrition it may not be accurate for non-Caucasians. BMI does not take into consideration ethnic and gender variations in body composition. In this recent study a low-dose X-ray (called DXA) was used to estimate fat mass, lean body mass and bone density. The study found that African American women may not always be overweight when their BMI is elevated. The researchers suggest that African American women may not be overweight until their BMI is greater than 32 (instead of 30).
This data needs to be further evaluated in other studies. At this point in time we recommend using several measurements to evaluate your weight status (body weight, percent body fat, BMI and waist circumference).