Health versus fitness: competing themes in the origins and spread of agriculture?

The general picture of human health that has emerged from bioarchaeological studies of the agricultural transition is one of health decline, although the nature and severity of the biological impacts have varied in accordance with worldwide diversity in the timing, duration, and specific characteristics of this economic shift. Conversely and somewhat paradoxically, the emerging picture has also been one of enhanced fertility and population growth. These findings raise challenging questions about the measures bioarchaeologists use to assess the biological costs and benefits of agriculture. It is argued here that these measures fall into two potentially quite distinct categories-physiological fitness (homeostasis) and reproductive (Darwinian) fitness, measures that may assess the costs and benefits of a biocultural system very differently. Both provide valuable insights into questions about our past at levels ranging from the evolution of our species to the unique experiences of individuals and their kin. However, the relative importance of each in larger questions about human adaptation needs to be carefully considered when assessing the biological evidence in questions of causation.