Most of metabolic studies in man concerning the ability of soya proteins to obtain an equilibrated nitrogen balance have been made with extruded products. Because of the extending development of spun proteins, it seems necessary to study the protein quality of this type of product. A preliminary study in rat (C.E.P. method) was conducted to improve the nutritional value by complementation of the fibers by the way of binder. The metabolic utilization of this protein was evaluated in human subjects during two periods of 10 days. Soya protein cover respectively 78 and 48% of the total protein intake. Under these experimental conditions in which soya proteins constitute an important percentage of the total protein intake, the mean nitrogen balance is near to be equilibrated and the nitrogen utilization does not present any significative difference between the periods. Parallely to the suppression of animal proteins, the introduction of insatured lipids in the diet, has allowed, moreover, to decrease the concentration of the lipidic parameters of the subjects. This study demonstrated the dietetic interest and the ability of the studied product to provide the supplying of the nitrogen balance.