Provided are a method for promoting the lipolysis and fatty acid oxidative metabolism in mammals or cells derived from mammals, a method for down regulating the fat content and the weight of a mammalian body, as well as a method for increasing the intracellular cAMP concentration, increasing the phosphorylation level and the activity of the hormone-sensitive esterase HSL, enhancing the transcription activity of PPAR± and increasing the activities of enzymes involved in a fatty acid ² -oxidation process. By mimicking the expression of a protein corresponding to a gene responsible for the phosphorylation of the Fas-associated death domain protein, or treating and acting on mammals or cells derived from mammals with a material that can increase the phosphorylation level of the Fas-associated death domain protein, said methods increase the phosphorylation of the Fas-associated death domain protein.
