1. The potential for forest foods to contribute to food security and better nutrition as elements of sustainable diets is largely untapped. Forest foods represent an affordable source of food, especially for those with limited livelihood options, supplying micronutrients, fibres and other key food components most commonly lacking from diets. 2. Full realization of the contribution of forest and tree foods to sustainable diets faces a number of constraints. Key among these are knowledge gaps, issues related to tenure and access, aspects of sustainability of extraction, and rapidly evolving social and cultural contexts, which have a significant impact on diets. Research is needed on all these topics. 3. There is a need to promote better integration of information and knowledge on nutritious forest and tree foods into national nutrition strategies and programmes. The establishment of crosssectoral policy platforms that bring together nutrition, food security, environment, agriculture, health, development, conservation and land-use planning would help achieve this.