Abstract: The present invention relates to the field of lipolysis mediated by lipases. In particular the present invention relates to the modulation of lipase activity by regulation of the composition of the interface between a hydrophobic and a hydrophilic phase. More particularly the present invention relates to a the use of a formulation comprising at least one surfactant with an interfacial pressure that is sufficiently high to control the access of lipase substrates to the interface between a lipophilic phase and a hydrophilic phase to regulate lipolysis and to a composition comprising at least one oil and enriched with at least one surfactant wherein the surfactant is non-cleavable by at least one lipase, has a higher affinity to the interface between the hydrophilic and lipophilic phase than the at least one lipid and is present in a weight ratio to the at least one lipid of about 1:1000-100:1.