From Wild Foods to Mixed Subsistence: Nonlinear Nutrition Transition among Hadzabe Foragers

Nutrition transition is often framed as a linear replacement of wild foods by market commodities. However, in contemporary small-scale societies embedded in dynamic social-ecological systems, dietary change is typically hybrid, reflecting reconfiguration of food environments rather than linear substitution. We analyze repeated cross-sectional 24-hour dietary recalls from Hadzabe adults (2015, 2019, 2025; n=202), classifying intake into locally salient wild foods (e.g., tubers, game, honey, fruits) and agricultural/processed categories to assess change in dietary composition and diversity. To contextualize interannual variability, we situate focal years within long-term hydroclimatic conditions (1981-2025) using CHIRPS rainfall and NASA MERRA-2 soil moisture and temperature data, while also considering regional tourism trends as coarse proxies of market access and cash income. Dietary change was strongly nonlinear: 2019 was the lowest-diversity year, while 2025 exhibited cross-domain dietary broadening, with expanded wild plant and honey consumption alongside increased agricultural foods, processed items, sweetened beverages, and alcohol. These patterns do not support steady erosion of wild subsistence; rather, wild foods persisted as market foods increased. Hydroclimatic and tourism data showed only partial correspondence with dietary patterns, suggesting that broad ecological and economic proxies incompletely capture how environmental and market change is mediated through provisioning decisions. Taken together, these findings indicate that nutrition transition in foraging populations is best understood as a socially mediated reconfiguration of mixed food systems.