After decades of growing reliance on international trade, recent changes has led countries to be also concerned with their capability to support national food security based on their domestic resources. National food self-sufficiency literature and assessment methods are roughly divided into the widely adopted "made-in" approach, which ascribes local produce to its last reported production point; and the "local potential" approach, which relies on yields to evaluate hypothetical local food availability. However, both paradigms disregard trade of supplementary inputs and products (e.g., animal feed, oil crops etc.) required for local production. Following the "weak and strong sustainability" paradigm, our research introduces the "weak and strong locality" perspectives. It compares between the "made-in" ('weak locality'- WL) to 'the strong locality' (SL) perspectives, which explores the local production capacity without supplementary inputs. The framework and its relevance to national food security are demonstrated using an empirical study of the Israeli food system along five decades. Results highlights that the local food supply based on the WL perspective is 1.4 times higher than the amount available based on the SL perspective. Restricting supplementary traded inputs affects mostly the local cereal, oil crops and livestock sectors. Beef, dairy, poultry and eggs production would reduce significantly, compared to WL quantities, which limits the local food system capacity to support only 22% of the Israeli population. These findings are relevant not only to other resource-limited (i.e. land and water) and trade-depended countries similar to Israel, but also to large and accelerating food markets.