A week of Danjiki (Buddhist fasting ritual) on cardiometabolic health: a case report

Danjiki is an ascetic traditional fasting ritual in the Japanese Buddhism training. Here we present a case of a 48-year-old man who underwent a 1-week-long Danjiki fasting ritual in a remote Buddhist temple. The daily ritual consisted of waking up at 3:30 am, hiking strenuously in the steep mountains followed by meditations on the rocks, focused calligraphy of religious drawings and documents, recital of Buddhist prayer chanting, and standing under waterfalls while reciting prayers. He was allowed to drink water ad libitum and a cup of carrot juice a day. After a week of the Danjiki ritual, his body weight decreased by 5 kg. Resting metabolic rate did not change. Fasting blood glucose did not change but plasma triglyceride decreased 35 %. There were no changes in blood pressure. Arterial stiffness increased 15-25 % and endothelium-dependent vasodilation decreased 5 %. These results indicate that the Danjiki ritual produced significant weight loss but unexpectedly reduced vascular functions.