The invention relates to the use of a composition comprising proteinaceous matter, said providing at least 24.0% of the energetic value of the composition (en %) and at least 12 wt. % based on proteinaceous matter leucine in the manufacture of a medicament for the treatment of insulin resistance and to a composition suitable for administration to a mammal comprising a protein fraction, a carbohydrate fraction and a lipid fraction, wherein the protein fraction provides at least 24.0 % (en %), the carbohydrate provides up to 46 en %, the lipid fraction provides up to 30 en % and wherein at least 12 wt. %, based on proteinaceous matter, of leucine.