Blood donation does not require fasting and should not be done on an empty stomach because if you fast before donating blood, hypoglycemia may be induced during the donation. After the donor develops hypoglycemia, he or she will experience a series of symptoms such as dizziness, excessive sweating, panic attacks, and in severe cases, coma and twitching of the limbs, which can threaten the donor’s health. Before donating blood, you can eat, but you cannot eat food that is too high in sugar, calories and fats, because after eating these high-calorie, high-sugar and high-fat foods, there may be an increase in blood lipids, which may induce celiac disease, commonly known as milk blood, and the quality of the blood donated will be reduced, and the blood may be substandard, wasting the blood supply. Therefore, you should not fast before donating blood, but you should pay attention to a light diet.