Transforming diets is critical for sustainable food systems. While there have been increasing global discourses on healthy and sustainable diets, national and local actions often remain limited. This paper addresses this gap by focusing on China, the world’s largest developing country. We examine the specific challenges of defining healthy and sustainable diets for the Chinese population by considering regional dietary cultures, affordability, and environmental impact. We analyze how policy interventions, including both supply and consumer-side strategies, can promote the transition towards such diets. The findings can offer valuable lessons for other developing countries facing similar challenges.