Composition comprising an aqueous liquid extract of phycobiliproteins, containing phycocyanin, which is obtained from cyanobacteria or micro-algae and which has not been subjected to any drying step, said composition being used to prevent or treat lipido-carbohydrate metabolism disorders in humans or mammals. In particular, the composition can be used to prevent or treat non-alcoholic hepatic steatosis or steatohepatitis.