Abstract: Ketogenic diet is a specific diet with very low carbohydrates, moderate to low protein and sufficient fat, which causes decreasing of blood glucose, insulin secretion, activity of insulin-like growth factor-1 (IGF-1) axis, and inhibiting in proliferation of cancer cells with hyperactivity of aerobic glycolysis. This paper reviewed on the safety of ketogenic diets and efficacy of nervous system tumors, prostate cancer, breast cancer and other tumors, as well as its synergistic effect with radiotherapy and vitamin D.