Eating a lot of watermelon can cause blood sugar to rise. Watermelon contains a certain amount of sugar and calories, and the glycemic index in the fruit is relatively high, 72, belongs to the high glycemic index food, eat 100-200 grams of watermelon per day on the postprandial blood glucose has less impact, so diabetic patients can eat watermelon, but if a large number of one-time watermelon is caused by large fluctuations in blood glucose, is not conducive to the control of blood glucose. General fasting blood glucose below 7mmol / L, 2 hours after the meal blood glucose control below 10mmol / L, glycated hemoglobin below 7.5%, blood glucose stability without significant fluctuations can choose to eat fruit. It is recommended that fruits with low sugar content, such as watermelon and peaches are optional. It is not recommended that diabetic patients choose tropical fruits with high sugar content, such as lychee, cinnamon, bananas, etc. Eating such fruits will have a greater impact on blood sugar. Eat fruit to pay attention to time, diabetic patients should be in the middle of the two meals will be fruit as a meal, especially at the table can not follow the crowd to eat the main meal and then eat fruit. In addition, when hungry or after physical activity can also eat some fruit in moderation. In daily life, healthy people or diabetic patients should follow a healthy diet, avoid eating foods with high glycemic index, appropriate physical exercise, diabetic patients should also be standardized under the guidance of the doctor medication.