The purpose of the present invention is to provide a method for producing fermented milk using a raw milk of low butterfat content wherein the present invention provides a low calorie and good flavored yogurt in which water separation is suppressed without the addition of a stabilizer and provides a method for producing the yogurt. This purpose is achieved by the method for producing a low calorie yogurt the method including a deoxygenation processing step for reducing the concentration of dissolved oxygen in the raw milk and a lactose degradation step for adding lactase to degrade the lactose in the raw milk preferably at a specified ratio of alpha lactoalbumin and/or beta lactoglobulin in the raw milk.
