San living in the northwestern Kalahari Desert may be grouped according to different kinds and proportions of dietary habits. At one end of a continuous scale are those whose food is obtained almost entirely from wild bush sources; at the other extreme are those who obtain large amounts of food from domestic sources, principally milk and maize meal. The majority fall between these poles. The region is also home to a substantial number of pastoralists and horticulturalists. Data have been collected on the productivity of both the natural and domesticated environments, on resource procurement strategies, and on food consumption during a period of more than 1 year. Seasonal weight fluctuations associated with food production cycles are recorded. Mean weight and serum lipid values are higher in those San who consume substantial amounts of domestic foods than they are in bush food eaters. Seasonal variation in fertility is reported to be coordinated with variations in nutritional status. Some implications for demographic and social processes are mentioned.