The vast heterogeneity in dietary practices across China has led to profound regional disparities in health and environment. To address this issue, we developed a region-specific reference diet (RRD) that is better aligned with Chinese culinary traditions, affordable, sparing of natural and environmental resources, and contributes to health. The adoption of the RRD has proven to be a viable solution to facilitate a rapid transition towards a healthy and environmentally sustainable diet across the country when compared to dietary guidelines from the World Health Organization, the EAT-Lancet Commission and the Chinese Nutrition Society. The RRD improved health in all regions and resulted in reductions of all five environmental impacts measured. Given China’s huge population and its major impact on global sustainability, the widespread adoption of the RRD would not only yield substantial health benefits domestically, but also contribute significantly to global food security and sustainability efforts.