Healthy diets are those diets that are of adequate quantity and quality to achieve optimal growth and development of all individuals and support functioning and physical, mental and social wellbeing at all life stages and physiological needs. Healthy diets are safe, diverse, balanced, and based on nutritious foods. They help to protect against malnutrition in all its forms, including undernutrition, micronutrient deficiencies, overweight and obesity and lower the risk of diet-related non-communicable diseases. The exact make-up of healthy diets varies depending on an individual’s characteristics (e.g. age, gender, lifestyle and degree of physical activity), geographical, demographical, cultural patterns and contexts, food preferences, availability of foods from local, regional and international sources, and dietary customs. Healthy dietary practices start early in life – breastfeeding fosters healthy growth and improves cognitive development and has long-term health benefits. WHO publishes guidance for healthy diets¹. Many national health authorities publish specific dietary guidance. Regional health organizations, where applicable, may publish documents related to healthy diets and specific dietary advice as well².

Healthy diets and sustainable food systems are interlinked in complex and multidimensional ways. The key concept of healthy diets through sustainable food systems entails the following elements. Sustainable food systems³ provide food and enable healthy diets, while achieving the three dimensions of sustainable development, for current and future generations. Sustainable production, including sustainably managing and using natural resources, biodiversity and ecosystems, while at the same time improving economic and social conditions and livelihoods of farmers, can support and contribute to healthy diets. Advancing innovative pathways to achieve sustainable consumption and production, in accordance with paragraph 38, significantly contribute to sustainable food systems. Context-specific changes, in line with national priorities and relevant international obligations, are needed across multiple sectors and policy areas in the process towards achieving sustainable food systems and improved nutrition for all.

Nutritious foods are safe foods that contribute essential nutrients such as vitamins and minerals (micronutrients), fibre and other components to healthy diets that are beneficial for growth, health and development, guarding against malnutrition. In nutritious foods, the presence of nutrients of public health concern is minimized.

Unhealthy diets are a major risk factor of multiple forms of malnutrition and poor health outcomes globally. Unhealthy diets include those of insufficient quantity and quality of nutrients and are a driver of hunger, micronutrient deficiency and undernutrition. Furthermore, unhealthy diets relate to the excessive intake of food and beverages high in fat, especially saturated and trans-fats, sugars and salt/sodium⁴, which can have an impact on increased risk of overweight, and to higher susceptibility to obesity and diet-related NCDs⁵.

Food systems shape people’s dietary patterns and nutritional status. Food systems are complex and multidimensional webs of activities, resources and actors involving the production, processing, handling, preparation, storage, distribution, marketing, access, purchase, consumption, and loss and waste of food, and the outputs of these activities, including social, economic and environmental outcomes. Food systems are constantly being shaped by different forces, drivers and structural changes and decisions by many different stakeholders that could affect their sustainability. Sustainable food systems have a fundamental role to play in promoting healthy diets and improving nutrition and enabling other public objectives of food systems. Sustainable food systems are food systems that enable food safety, food security and nutrition for current and future generations in accordance with the three dimensions (economic, social and environmental) of sustainable development. Sustainable food systems must be inclusive, equitable and resilient.

Agriculture includes crops, forestry, fisheries, livestock and aquaculture⁶. Agriculture and food systems encompass the entire range of activities involved in the production, processing, storage, marketing, retail, consumption, and disposal of goods that originate from agriculture, including food and non-food products, livestock, pastoralism, fisheries including aquaculture, and forestry; and the inputs needed and the outputs generated at each of these steps⁷.

The functionality of food systems and their ability to deliver healthy diets is influenced by a number of drivers which indicate that, in order to ensure food security and improve nutrition, context specific changes are needed not only in agriculture and food policies, but also across multiple sectors and policy areas that address, for example, national development priorities, economic policies, and social norms⁸. These context specific changes may require tailoring approaches to address the different drivers of poverty and inequities across populations.

The process towards achieving sustainable food systems that meet the dietary needs of populations, recalling that transformation of food systems should be encouraged in a coherent manner, as appropriate and in accordance with and dependent on national contexts and capacities, require policy, institutional and behavioural changes which are context-specific among food system actors. Food system-related policies should focus on their direct and indirect economic, social, environmental, cultural, nutritional, and health impacts, paying special attention to the poorest and most vulnerable to all forms of malnutrition and addressing barriers they face in accessing food for healthy diets through sustainable food systems.

Changes are needed within and across food systems, and their constituent elements - food supply chains, food environments, consumer behaviour - to generate positive outcomes along the three dimensions of sustainable development – social, economic, and environmental, with inclusive approaches for all relevant stakeholders.