According to the She-sheng hsiao-hsi, or Tidings of Good Health, by Ch'iu Ch'u-chi (1148 to 1227), more sour foods should be eaten in summer in order to build up the liver, which has just undergone its greatest period of activity during the previous season, and fewer bitter and sweet things.
據元朝邱處機「攝生消息」的說法，夏天應多吃些酸味，可為上一季活動旺盛的肝做些「滋補」工作，但記得減少苦味及甜味。