Most saline/hypersaline lagoons and lakes are in arid regions, where the problems of freshwater and food shortages are particularly acute. More than 70 % of the freshwater people consume is used for agricultural purposes, i.e., food production. There is a contradiction between satisfying two human needs: food and fresh water. It is extremely necessary to find a way to address this contradiction, which cannot be done without going beyond the traditional approaches. To overcome the contradiction between freshwater conservation and food production is to reduce the role of freshwater bodies in food production. One of the most promising ways is to transfer this function to saline water bodies, primarily lagoons and lakes. Natural possibilities for this are enormous, including the use of valuable biomass produced by macroalgae and plants in saline lagoons and lakes. The goal of this review, by summarizing the results of our own and available literature data, is to highlight the enormous potential that is currently underestimated, despite growing interest in it over recent years. This review demonstrates that Cladophora (green algae), Ruppia (aquatic plants), and halophilic plants exhibit high productivity and possess the greatest potential for widespread application. The use can facilitate the transfer of some agricultural/aquaculture pressure from freshwaters to saline waters.