The policy implications of a model of contemporary food systems for developing countries that integrates nutrition, reduction of disease risk, culture, income generation, and biodiversity are reviewed within a theoretical and empirical examination of the relevance of nutrition to the priorities put forward at the World Summit on Sustainable Development in Johannesburg, South Africa, 2002. Agricultural, health, economic, and social policies with local reach are necessary responses to the increase in noncommunicable disease associated with the globalization of food systems. Nutrition offers a nexus for the changes in individual behavior and motivation essential for fundamental shifts in production and consumption patterns. Mutual consideration of biocultural diversity and nutrition can guide policy, research, promotion, and applied action in developing countries. Benefits from enhanced use of biodiversity must legitimately flow to the undernourished poor, while potential negative consequences must be minimized and mitigated. Quality and quantity of food need not be mutually exclusive. Functions related to energy density, glycemic control, oxidative stress, and immunostimulation define important research priorities. Tests of the hypothesis that biodiversity equates with dietary diversity and health might combine quantitative indicators of dietary and biological diversity with nutrition and health outcomes. Biodiversity, where it is part of traditional agricultural and food systems, can be best conserved and enhanced through rational use within a broad-based developmental focus on small-scale and low-input production. The fact that traditional systems, once lost, are hard to recreate underlines the imperative for timely documentation, compilation, and dissemination of eroding knowledge of biodiversity and the use of food culture for promoting positive behaviors.