All the volunteers have a visit of inclusion in the Centre de Recherche en Nutrition Humaine. During this visit, the volunteers are informed of the methods of the protocol, the taking of samples, the disadvantages and constraints, on the basis of information letter. They have a medical interrogation and a complete clinical examination by an investigatory doctor or Co-investigator. The biological assessment is requiring 10 ml of blood and including: the analysis of the TSH, a blood count, a sedimentation test. Moreover, for the women in age to procreate, the analysis of the beta - HCG is made. To take another blood sample (10 ml) is necessary for the realization of serology HIV/HCV in the volunteers of the group of doubly labeled water, who provide samples of urine and saliva. The results are communicated to the volunteers confidentially.