Strategies for achieving healthy, sustainable, and equitable dietary transitions.

The industrialization of global food systems has led to dietary changes that harm both health and the environment. If global food systems are to meet the needs of a growing population for healthy, environmentally sustainable, and affordable diets, substantial changes will be required. In this Review, we synthesize growing empirical evidence on the complexity of factors that influence consumer dietary and farmer production choices, especially the roles of public and private entities that shape food environments. We outline promising interventions to help facilitate beneficial global dietary transitions, including research and development for product innovation, regulation of food environments, and food assistance and food-as-medicine programs. Understanding and aligning the motives and incentives of various food system actors is essential to achieve improved health, environment, and equity outcomes. Editor's summary: Our current food systems are major sources of pollution, greenhouse gases, and land-use change while also struggling to provide adequate nutrition equitably to more than 8 billion people. As development and incomes increase, people are shifting their diets toward more meat and processed foods, with negative effects on both human health and the environment. Yang et al. synthesized research on leverage points for more sustainable and healthy dietary transitions. They highlight the outsized role of midstream actors, including manufacturers, retailers, and restaurants, in influencing consumer choice and farmer actions. A combination of research and development, regulation, education, and public assistance could help make healthy and sustainable foods more tasty, available, and affordable. —Bianca Lopez BACKGROUND: Rising incomes, urbanization, agricultural industrialization, and the steady rise of ultraprocessed foods are driving a global transition to unhealthy diets with insufficient consumption of vegetables, fruits, legumes, whole grains, and nuts and excess consumption of animal-sourced foods and foods high in sugars, refined starches, sodium, saturated and trans fats, and artificial colors and preservatives. This transition is occurring in rich and poor countries alike, exacerbating noncommunicable diseases, environmental degradation, and social inequity. Challenges differ across geographies. Whereas high-income countries grapple with overconsumption and greenhouse gas emissions, low- to middle-income countries suffer undernutrition alongside rising obesity and rapid deforestation, often exacerbated by global trade dynamics. Although researchers have long recommended dietary patterns that improve both human and planetary health, large-scale transitions toward sustainable, healthy, and affordable diets remain elusive. Dietary behaviors are difficult to change because they are shaped by a complex web of influences, from direct factors—such as taste, affordability, convenience, and culture—to indirect forces rarely noticed by consumers, including food industry marketing, reformulation, product displays in groceries, and product innovation. As a result, nudges that target individual consumer and producer behavior have limited impacts because they are often overshadowed by larger, systemic influences of the broader food environment, driven especially by midstream actors in food value chains (for example, food manufacturers, retailers, and restaurants). Acknowledging the deeply behavioral and systemic roots of dietary outcomes and their sustainability, health, and equity impacts, this Review focuses on the complex interplay of demand-side, primary production, supply chain, and institutional drivers that shape food systems and their impacts. ADVANCES: This Review connects the behaviors of consumers, producers, and the midstream actors who influence both supply and demand. It then proposes solutions based on syntheses of evidence across major intervention domains: (i) research and development (R&D) for product and process innovation, to increase the sensory appeal, productivity, and affordability of healthy and sustainable food products; (ii) affordability and access, particularly through food assistance programs and supply chain innovations and policies to internalize health and environmental spillovers; (iii) food-as-medicine initiatives that integrate nutrition into health care; (iv) regulatory changes to shape food environments that encourage healthy and sustainable consumer behaviors; (v) public procurement policies that set sustainability and nutrition standards; (vi) metrics and data systems to ensure accountability; and (vii) strategies to change consumer education and social norms to promote lifelong food literacy and healthy, sustainable eating habits. A key insight from this wide spectrum of evidence is that the knowledge or willpower of consumers and producers is often overridden by the food environments shaped by midstream food value chain actors, especially through procurement contracting; marketing; and by-product formulation, taste, availability, and affordability. OUTLOOK: Transitions to more sustainable, healthy, and equitable global diets require coordinated, systemic innovations across multiple domains, combining multiple of the seven key areas for intervention highlighted in this Review. A central task is to align the incentives of consumers, producers, and powerful midstream actors such as restaurants, retailers, and food manufacturers. These actors, if properly engaged, can help identify locally appropriate combinations of regulation, technological innovation, and civil society engagement to reshape food environments and drive large-scale dietary change toward societal sustainability, health, and equity goals. Attention must also be paid to emerging influences from outside the traditional food system, such as GLP-1–based neuroregulatory drugs, which may shift food preferences and purchasing behaviors through biological mechanisms rather than cultural, economic, or informational ones. Future research should include more rigorous evaluation of key interventions, particularly their long-term effects; examine the potential of emerging technologies such as online food delivery platforms to influence large-scale behavior change; and investigate how medical innovations may intersect with and reshape food environments. The many midstream actors that shape consumer food choices and producer choices within food systems and key levers to facilitate transitions toward healthier and more sustainable and equitable diets.: [ABSTRACT FROM AUTHOR]