The Biomatic is a device allowing the thorough follow up of the body composition by multi-frequency bio-impedancemetry, for a better understanding. Applications The Biomatic offers a complete and trustful information in many applications such as setting and follow up of a diet, a physical training, a check-up or any specific treatment. In this way, the Biomatic becomes a very useful tool for nutritionists and dieticians, sport doctors and instructors for amateurs or professionals (sport centre or club), general practitioners (obesity or diabetes troubles, annual check-up...), spa centres, etc. Procedure Through 2 pairs of electrodes placed on each hand and foot (same side), the Biomatic will emit a very low frequency current between both distal electrodes. The different frequencies of 1KHz 5KHz 10 KHz 50 KHz 100KHz will allow to measure different ratios about the intra- and extra-cellular total body composition (upper part and lower part), distinguishing the fat body mass, the lean body mass and the water in the body. Mesured parameters BMI, Fat Body Mass (kg, weight % and index), Total Lean Body Mass (kg, weight % and index), Lean Body Mass anhydrous (kg, weight % and index), Total water (L, weight %, Lean Mass % and index), Active cellular mass, Extra-cellular mass, Ratio Active cellular mass to Extra-cellular, Ratio Active cellular mass to Lean mass, Active cellular mass indexed (reflect of basal metabolism), Exchangeable potassium, Ratio Sodium to Potassium, Ideal weight and Nutritional index.