The objective of the present invention is to provide a method for preparation of an oil-in-water emulsion, such as a mayonnaise, having a reduced oil content. Such reduced oil emulsion nevertheless should have the same properties as the higher oil variants. This objective has been met by a method wherein a dispersion of cellulosic fibres is heated, before being mixed with other ingredients of the emulsion. Either the dispersion of cellulosic fibres is homogenised in a high pressure homogeniser at relatively high pressure, or the final emulsion containing the dispersion of cellulosic fibres is homogenised in a high pressure homogeniser at relatively high pressure.