The glycemic index of water chestnut is high, but the exact value is not authoritatively recorded. Water chestnut belongs to miscellaneous grain starch food, after consuming it, starch will be absorbed and converted into glucose in the body, its glycemic index is higher and its sugar content is also higher. However, its glycemic index is lower compared to fine rice and noodle products, so patients with high blood sugar can consume water chestnuts as a staple food, and can take cooking methods such as boiling and steaming. In addition, starchy foods belonging to the category of miscellaneous grains include yams, groundnuts and potatoes. It is recommended that patients with high blood sugar should pay attention to the amount of water chestnuts they consume, and should not consume too much at one time, so as to avoid a significant rise in blood sugar. Consult your physician or dietitian for specific dietary combinations.