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.
