Currently there is no research to show that too much sugar intake will cause the brain to become stupid, sugar is an indispensable substance for the human body to provide energy, moderate intake to maintain the normal function of the body. Sugar is the body’s three major energy substances, through the sugar metabolism to maintain the normal functioning of the body, sugar should be appropriate intake, excessive intake may lead to the accumulation of fat, resulting in obesity, affecting the normal health of the body. If the intake is reduced will lead to hypoglycemia, causing dizziness, fainting, and even poor nutritional status, and there is no sugar eaten too much will lead to intellectual decline, the brain becomes stupid definite evidence. For diabetic patients, it is more important to control the intake of sugar, pay attention to diet, eat more coarse grains, normal people should be appropriate intake of sugar, to avoid excessive intake of sugar leading to obesity or malnutrition.