The world faces a double challenge in human nutrition: meeting energy and nutrient requirements to overcome and prevent undernutrition, and achieving a diet that helps to prevent caloric overnutrition. These goals can be achieved using bioactive plant compounds from vegetables and fruits, which are usually available locally when food sovereignty is respected.The world faces multiple challenges to nutrition, from hunger and undernutrition, nutrient deficiencies, and disease-related malnutrition on one end to caloric overnutrition leading to overweight and obesity on the other end (Keding et al., 2013;Steyn and McHiza, 2014). In fact, these ends are not far from each other but rather two sides of the same coin and -perhaps unexpectedly -they occur in developing, 'emerging' and industrialized countries, at the national, regional, community and family level.Before a healthy diet can be considered, nutrition security is a prerequisite. As illustrated in Figure 1, there are preconditions in the fields of agriculture and food systems, care and health. All of these together facilitate nutrition security and are the basis for a healthy diet. As many contributions to this issue of the journal illustrate, nutrition security demands primarily political and economic answers: poverty, land rights, gender equality, market access as well as other social and cultural issues. Still, a nutritional perspective keeping in mind human requirements can contribute to identifying appropriate solutions to nutrition challenges.
Diets, food, nutrientsFundamental to a healthy diet is the safe provision of all nutrients, water and energy. This is usually addressed when food plants and animal-derived foods are considered as the basis for human diets. A somewhat misleading nutritional science has taken the attention away from diets and focused on macro-and micro-nutrients only. This has shifted policies and interventions more towards supplementation and fortification (or biofortification) of micronutrients and food energy and away from sustainable food systems (MĂŒller and Krawinkel, 2005;Flynn et al., 2009). In the field of development cooperation, diets based on the nutritional value of natural foods are often neglected,