Dietary and policy priorities to reduce the global crises of obesity and diabetes

The world faces a global nutrition crisis, most clearly evidenced by the twin pandemics of obesity and type 2 diabetes (T2DM). Yet, substantial confusion and controversy exist about optimal dietary priorities and policy approaches to address these challenges. This paper reviews the evolution of nutritional evidence, emerging areas and corresponding policy lessons to address obesity and T2DM. This includes the complexity of diet–health pathways for long-term weight maintenance and metabolic health; a need to focus on both increasing protective foods (for example, minimally processed, phytochemical-rich foods) and reducing detrimental factors (for example, refined starches, added sugars and processed meats); and critical assessment of popular diets for weight-loss and metabolic health. Emerging evidence highlights areas for further research, including those related to food processing, non-nutritive sweeteners, emulsifiers, the microbiome, flavonoids and personalized nutrition. Evidence-based, multi-sectoral policy actions to address the global nutrition crisis are shown to span several domains, including health systems, economic incentives, school and workplace environments, quality and labelling standards, and innovation and entrepreneurship. Diet and policy approaches to curb obesity and type 2 diabetes can be contentious and confusing. This Review synthesises state-of-the-art and emerging evidence on diet and health, reflects on policy and reconciles the evolution of the discipline of nutritional science with changes in dietary advice.