The paper reveals the mechanisms of adaptation of food markets in the western borderland of Russia to the integration and disintegration processes that have been taking place on the external and internal borders of the Eurasian Economic Union since 2014. Using the example of the Kaliningrad and Smolensk oblasts, the authors identified changes in the regional food base under conditions of active import substitution, assessed the changes in food preferences of the population, as well as the role of cross-border practices in meeting the population's food needs. Based on the analysis of regional and federal statistics and field research, it was possible to establish that against the background of active investment in agriculture and food production there were three parallel processes: the spatial contraction of agricultural production, the expansion of its production capacity by large agricultural holdings in strictly defined areas (around regional capitals and important transport routes), and the expansion of holdings in selected peripheral areas with the lowest land value. Despite the commonality of the processes, the performance in agriculture and food production and activity in obtaining state support in Smolensk and Kaliningrad oblasts are radically different. Visual inspection of retail outlets, discourse analysis and representative surveys of the population allowed us to conclude that import substitution only partially allowed to provide raw materials and final products to regional food markets in both regions, since most holdings are oriented to meet the demand in high-margin markets inside and outside the country. Food markets in border regions are characterized, on the one hand, by greater vulnerability to integration and disintegration processes, and, on the other hand, by the variability of choice and opportunities for cross-border shopping trips. However, empirical data obtained by sociological methods show that the widespread perceptions of high cross-border mobility of the population of border regions are highly overestimated. The populations of Smolensk and Kaliningrad oblasts are similar in the level of mobility and conservatism with regard to shopping for goods of specific manufacturers of a suitable price segment. The “network” (through intermediaries) penetration of “sanctioned” goods in the Kaliningrad oblast covered a much larger share of the population than that which directly traveled abroad for shopping, so the adaptation of the population to external challenges to the food market was more noticeable.