Dizziness before meals is considered to be caused by hypoglycemia after meals. For the hypoglycemia is serious, can appear hypoglycemic encephalopathy, the patient can be mildly manifested as dizziness, headache, as well as panic, sweating, blurred vision, weakness and so on. For patients with diabetes mellitus, if long-term hypoglycemia tolerance, the patient will not have symptoms of sympathetic excitation due to hypoglycemia, but only dizziness, mainly due to the lack of oxygen and sugar in the brain after hypoglycemia, glucose is the main source of energy in the brain, especially in the brain, and when there is hypoglycemia in the human body, there will be ischemia, lack of sugar, lack of oxygen in the brain, which can be manifested as headache, dizziness, amnesia, and in severe cases, the patient may have headache, dizziness, amnesia, and in severe cases, the patient may have dizziness. Dizziness, forgetfulness, and in severe cases, mental disorders, disorientation and memory loss can occur Sometimes, seizures can also occur.