Disclosed is a method for reducing the sterol, for example cholesterol, content of sterol-containing substances such as fats and oils. The method provides an efficient and cost effective process based on the affinity of cholesterol and other sterols for amphipathic molecules that form hydrophobic, fluid bilayers, such as phospholipid bilayers. Aggregates of amphipathic molecules are contacted with, for example, a sterol-containing fat or oil in an aqueous environment and then mixed. Following adequate mixing, the sterol-reduced fat or oil is separated from the aqueous separation mixture. Alternatively, the correspondingly sterol-enriched fraction also may be isolated from the aqueous separation mixture.