Mountain communities are considered particularly vulnerable to food insecurity, and their vulnerability is sometimes assumed to be increasing because of a loss of food self-sufficiency. Based on a case study of Nagar District in the Karakoram of northern Pakistan, the present article challenges this assumption by taking a broader perspective on food systems and their changes in recent decades. Defining food security as the outcome of a resilient food system, it investigates how major transformations of livelihoods and farming systems since the 1970s have increased or decreased the resilience of food systems in Nagar in various ways. Based on empirical field research conducted between 2014 and 2016, the study finds that local food systems have transformed from largely subsistence-oriented systems of food production and consumption to increasingly complex, multilocal networks in which off-farm livelihoods, external markets, and government-subsidized food supplies play central roles. This process of diversification of food systems has generally improved communities' resilience to food crises, despite the emergence of various new risks. The article argues that rather than overemphasizing local food self-sufficiency, research and policy related to food security in mountains must address the multidynamic and multifaceted character of food systems, as local production constitutes only one of several interrelated elements.