In recent years the influence of daily diet on tumor progression has received extensive attention with the research on the nutrition method and metabolic pathway in tumor cells much deeper. It is generally recognized that compared with normal cells most tumor cells are highly dependent on the aerobic glycolysis based on glucose to obtain energy whereas unable to utilize amino acids and ketone bodies. Therefore it is proposed to cut off the nutrient source of tumor cells through restricting carbohydrate intake thus restraining tumor cells from growing and divising. This review aims to describe the nutritional and metabolic mechanism of tumor cells concisely and discuss about the effects low-carbohydrate ketogenic diet has on the apparence and metabolism of tumor cells from various perspectives.