A building body of evidence is indicating that carbohydrate restriction can be a viable treatment for certain cancers. Restricting carbohydrates can slow or stop tumor growth, enhancing the treatment for cancer patients and even extending their survival. Benefits for the treatment of cancer are shown when carbohydrates are restricted to 20% of total calories or less. Most of the research is using the ketogenic diet, which restricts carbohydrates to 10% or less of total calories. More research is needed on if carbohydrate restricted diets with also work for cancer prevention.