A method for the use of lupin conglutin gamma or of proteins showing homology higher than 50% with lupin conglutin gamma, for the preparation of a medicament, food supplements or foods for the treatment of type II diabetes, pharmaceutical and nutritional compositions containing lupin conglutin gamma, and the use of lupin conglutin gamma as therapeutical agent, in particular as hypoglycemizing agent. Lupin conglutin gamma may be used in pure form or in form of extracts, mixtures or concentrates.