Let’s look first at body mass index (BMI). As a convenient, internationally accepted, cost-effective measure to access adiposity (fatness), BMI has become a widely popular tool among epidemiologists and health professionals. BMI is calculated as weight (kg)/height(m). Among adults, there are four BMI categories: underweight (less than 18.5-24.9); overweight (25-29.9); and obese (greater than 30)