We first analyzed the dietary records at a Zen monastery from the viewpoint of nutrition and food intake. The means of the total energy, protein and fat intake were significantly lower than a normal diet. The amounts of other nutrients had the same tendency. The mushrooms and seaweed intakes were extremely better than any other food groups. In addition, we conducted investigations regarding the diet and health of Zen monks training at Zen monasteries to examine their nutrient intake and health condition. The nutrient consumption of Zen monks was high carbohydrates, high dietary fiber, low fat, and low cholesterol, and this was especially conspicuous in the non-animal food consumption group. There were no concerns about their blood parameters. However, a decrease in their QOL is a concern. Finally, to clarify the difference in the serum lipid and blood glucose levels between young Zen monks and middle-aged Zen monks, we investigated their nutrient intake and health conditions. In both groups, no distinct difference was observed in their HDL cholesterol and triglyceride levels. However, the total cholesterol and blood glucose levels of the young group were remarkably higher than those of the middle-aged group. Therefore, this study suggested that physiological changes in the body due to aging affected the total cholesterol and blood glucose levels.