Nutritional status is the results of nutrients intake, absorption and utilization, able to influence physiological/pathological conditions.

Obesity is a worldwide epidemic, there is an increasing interest for body composition study to monitor conditions and delay in development of obesity-related diseases.

The need of standard assessment of nutritional status based on body weight changes, playing an important role in several clinical setting in pathologic condition and illnesses.

Since body mass index has been shown to be an imprecise measurement of fat-free and fat mass, body cell mass and fluids, providing no information if weight changes is better way to evaluate body composition.

Nutritional status can be measured with different techniques and monitoring body composition can be very useful for nutritional and medical interventional.

This review is focused on the use of Body Composition in Clinical Practice.