A new study presented at the Radiological Society of North America (RSNA) annual meeting reveals that having more muscle and a lower ratio of visceral fat to muscle is linked to a younger biological brain age. Researchers from Washington University School of Medicine in St. Louis found that individuals with healthier body compositions—specifically higher muscle mass and less deep abdominal fat—tended to have brains that appeared biologically younger on MRI scans. Visceral fat, the fat stored around internal organs in the abdomen, is known to be more harmful than subcutaneous fat, which lies just under the skin. The study analyzed whole-body MRI scans from 1,164 healthy adults with an average age of 55.17 years across four research sites. Using advanced AI algorithms, researchers measured muscle volume, visceral fat, subcutaneous fat, and predicted brain age based on brain structure. The results showed that higher visceral fat relative to muscle mass was strongly associated with an older-looking brain. In contrast, subcutaneous fat showed no significant link to brain aging. Participants with greater muscle mass tended to have younger-looking brains, reinforcing the idea that muscle plays a protective role in brain health. Senior author Cyrus Raji, M.D., Ph.D., emphasized that these findings validate the connection between physical health and brain health. “Healthier bodies with more muscle and less hidden belly fat are more likely to have healthier, youthful brains,” he said. “This lowers the risk for future brain diseases like Alzheimer’s.” The study highlights the potential of whole-body MRI and AI-driven brain age prediction as tools for monitoring health and guiding interventions. These tools could help track progress in programs aimed at reducing visceral fat while preserving or increasing muscle mass. The findings also have implications for the use of GLP-1 weight loss drugs like Ozempic. While effective at reducing body fat, these medications may also lead to muscle loss. Dr. Raji suggested that future therapies should aim to reduce visceral fat without compromising muscle. “Losing fat—especially visceral fat—while preserving muscle volume would offer the best benefit for brain aging,” he said. This insight could guide the development of optimized dosing strategies and new treatments that prioritize both body and brain health. The research provides a scientific foundation for including body composition metrics in clinical trials and metabolic interventions, underscoring the importance of maintaining muscle and minimizing deep abdominal fat to support long-term brain health.