They used mice that were genetically likely to develop intestinal tumors and compared animals eating a ketogenic diet with mice eating either a regular diet or a high-calorie, high-fat diet. Mice on the ketogenic diet developed many more tumors in the small intestine than mice eating a normal diet. Their cancer risk was similar to, and sometimes even greater than, that of mice eating the calorie-rich diet, despite the ketogenic mice remaining relatively lean. Future human research will determine whether these findings should influence dietary advice for people at high risk of intestinal cancer. If you care about cancer, please read studies that artificial sweeteners are linked to higher cancer risk, and how drinking milk affects risks of heart disease and cancer.