Predigestion as an evolutionary impetus for human use of fermented food

Fermented foods are an important part of the human diet. While the types of fermented foods consumed as well as the processes used to create them vary regionally, the majority of human populations globally deliberately produce and consume fermented foods as a central part of their diets. This pattern is in contrast to that of other vertebrates, including nonhuman primates. However, it remains unclear when and why humans began to include high amounts of fermented foods in their diets. Here, we review existing knowledge regarding the timing and impetus for the emergence of fermented food use by humans and put forth a new hypothesis that fermented food use began as a “predigestion” strategy to increase nutrient availability in harsh, terrestrial environments with physically and chemically defended food resources. We explore support for this hypothesis in comparative behavioral and physiological data from extant nonhuman primates. Together the data presented in this paper suggest that food fermentation may have had an impact on human evolutionary trajectories via interactions with human biology and health. Future work should build on this foundation to interrogate these processes in more detail.