This paper focuses on the relevance of endogenous preferences for the explanation of consumer behavior and its role for sustainable development. The demand side has received far less attention in the sustainability discussion than the production side. There seems, however, little doubt that consumption is equally as important for achieving sustainability (e.g., F. Duchin, G.-M. Lange, The Future of the Environment: Ecological Economics and Technological Change, Oxford University Press, New York, 1994). While the influence of social interaction of preferences has been pointed out by economists for centuries, this link is generally submerged in the standard economic assumption of individual interest maximizing behavior. With reference to a specific type of local food market (community supported agriculture groups, CSA), this paper investigates consumer behavior and its relevance for sustainable development. Several studies have investigated CSAs' contributions to different aspects of sustainable development and barriers to their expansion. One aspect usually left out is the change in preferences after interaction with the farmer/s and other market participants for several years. This learning aspect may, however, prove crucial to identify paths towards sustainable development.