Body mass index
Your weight matters, but it has to be considered in the context of how tall you are. Body mass index takes the two numbers into account. Like waist circumference, BMI is an indirect measure of risk, but a higher measure correlates with greater risk. The catch, however, is that it is not always entirely accurate. A person in excellent condition who has a lot of muscle mass may have a high BMI.
Too much excess weight is associated with diabetes, heart disease and stroke, some cancers, sleep apnea, osteoarthritis, fatty liver disease, and complications in pregnancy.
Bottom line: People with BMIs less than 18.5 are underweight. Target BMI range is between 18.5 and 24.9. Overweight is considered between 25 and 30, and a BMI above 30 puts you in the obese category.
(credits to YahooNews)