Lorelei Mucci, ScD, MPH, of the Harvard T.H. Chan School of Public Health in Boston, and colleagues reported in JAMA Network Open that among 4,884 men with nonmetastatic prostate cancer, the highest level of post-diagnosis saturated fat consumption was associated with greater all-cause mortality than the lowest level (HR 1.24, 95% CI 1.05-1.47). ^[1] A study published in JAMA Network Open on 2026-01-01 analyzed data from nearly 5,000 men with nonmetastatic prostate cancer followed for a median of 12.8 years. ^[2] Researchers from the Research Institute of the McGill University Health Center and Harvard T.H. Chan School of Public Health found that higher saturated fat intake and higher animal fat consumption were associated with greater all-cause mortality. ^[3] In an accompanying commentary in JAMA Network Open, David-Dan Nguyen, MDCM, MPH, of the University of Toronto, and colleagues said clinicians should not present dietary fat modification as a proven prostate cancer-directed therapy, but should not ignore the opportunity to promote diet, physical activity, smoking status, and cardiometabolic risk improvements after diagnosis. ^[4] Men with the highest saturated-fat intake had a 24% higher rate of death during follow-up than those with the lowest intake. ^[5] Replacing about 10% of daily calories from animal fat with plant-based fat was associated with a 16% lower rate of death from any cause. ^[6]