Central to successful attempts to address food insecurity in Africa are understandings of the historical contexts and meanings of food systems. However, much research into current challenges remains separated from deeper agrarian and alimentary histories. Using qualitative data on food within the historical record alongside the wider multidisciplinary record of the past, this Review traces long-term patterns and drivers of continuity and change in eastern African food systems. Considerable dynamism in place-based and regional trends in the integration of new foodstuffs, agricultural commercialization, resistance and transformations in diets, and diversification and specialization as livelihood strategies is found-each of which emerged within imbricated contexts of African agency, transoceanic exchanges and colonial incursions. Such historical data provide important deep-time perspectives for interventions to address modern food insecurity, as demonstrated through examples of agricultural value chains, 'under-utilized' crops and major infrastructure projects in southeast Africa.