Overview
- A Nature paper published July 15, 2026, by an MIT-led team found that mice genetically prone to intestinal cancer developed more tumors in the small intestine when fed a ketogenic diet while showing fewer colon tumors.
- Follow-up experiments in the study showed the effect was driven by fatty acid oxidation in intestinal cells activating PPAR proteins, which increase stem cell division and raise the chance of cancer.
- The researchers found circulating ketone bodies such as β-hydroxybutyrate did not cause the tumor changes, so ketone supplements are not expected to reproduce the study’s risks or benefits.
- Mice on the ketogenic diet stayed lean but had small‑intestine tumor rates similar to or higher than mice on a high‑fat, high‑calorie obesogenic diet, highlighting that fat metabolism rather than obesity drove the result.
- The authors stress the finding comes from a genetically predisposed mouse model and call for human-focused research before drawing clinical conclusions, noting small‑intestine cancer is rare but has risen in recent decades.