Food security is increasingly influenced by multilateral trade systems and foreign trade policies implemented by national governments. Many of them are now concerned about the sustainability of food supply and the vulnerability of domestic food markets to price volatility, and seek to support domestic producers and protect themselves from increasing food imports. Such restrictions improve food self-sufficiency, but decrease food security. It is important to understand any changes that may have occurred in the food consumption pattern due to trade protectionism and to observe any nutritional implications of these changes. This paper employs the rational food security (RFS) assessment approach, which differentiates sources of food supply on the domestic market, assesses the influence of agricultural and trade frameworks on food consumption patterns, and complies consumption with the appropriate food intake threshold. In the case of Russia, the study demonstrates that the conventional consumption approach to self-sufficiency (FSCA) underestimates the food insecurity level by not accounting for nutrition factors. In addition, the gap between the FSCA and the RFS increases in times of protectionist trade policy and decreases when the agricultural and trade policy framework turns to liberalization. The paper concludes that trade protectionism challenges the sustainability of food supply by decreasing food availability and quality of food products, causes dietary changes, and threatens the food security of the country.