Ketogenic diet is a high-fat, high-protein, low-carbohydrate diet. The effects and side effects of ketogenic diet on diabetic patients are as follows: First, the low carbohydrate content of ketogenic diet can reduce the functional burden of pancreatic beta cells in patients, which is conducive to the control of blood glucose in diabetic patients, and can also reduce body weight and blood lipids. Second, the ketogenic diet may lead to elevated blood lipids in diabetic patients, resulting in increased disorders of lipid metabolism. Third, for diabetic patients, the body’s intake of carbohydrates is too little, fat decomposition increases, and ketone bodies are easily produced, and the accumulation of ketone bodies will cause diabetic ketosis, and ketoacidosis occurs in serious cases. Therefore, for the ketogenic diet, although it is good for controlling blood sugar, it is not recommended for diabetic patients to have a strict ketogenic diet to avoid diabetic ketosis or diabetic ketoacidosis.