what is obesity?

In clinical practice, body fat is most commonly and simple estimated by using a formula that combines weight and height. The underlying assumption is that most variation in weight for persons of the same height is due to fat mass. The formula most frequently used in epidemiological studies is body mass indexs (BMI) which is weight in kilograms divided by the square of the height metreS . BMI is strongly correlated with densitometry measurements of fat mass adjusted for height in middle-aged adults. The main limitation of BMI is that it does not distinguish fat mass from lean mass.