The "Ten Tennis Principles" of a healthy diet is to ensure that the main food intake every day is ten tennis balls. Among them, the meat does not exceed the size of a tennis ball; Staple food (rice, noodles, cereals, etc.). ) is equivalent to the size of two tennis balls; Ensure three tennis-sized fruits; No less than four tennis ball-sized vegetables, ten tennis balls are 1, 2, 3, 4, one * * * ten tennis balls. This is the result of American research.