The demand for food is influenced by population size, type of diet and the amount of loss/waste of Agricultural products. In the present study, the amount of demand affected simultaneously by the influencing factors for the present time period, 2030 and 2050 were examined. The study examined 48 different scenarios derived from combining three levels of loss/waste reduction (0, 25, and 50%), four different food baskets, and four different fertility rates (including the current constant (1.8), low (1.5), medium (2.5) and high (3.3) fertility rates) for each of the 2030- and 2050-time frames, and calculated the demand values for plant products and blue water footprint required for each scenario. The amount of blue water footprint required to produce the products in demand was calculated according to the current farm management conditions of agricultural production. In the calculation of blue water footprint, the effect of climate change for the time points of 2030 and 2050 was also taken into cosideration. The results showed that the current demand for plant products in the country is 128.74 million tons per year. Assuming a population increase at the current fertility rate (1.8), the demand will be 149.25 million tons in 2030 and 166.06 million tons in 2050. The amount of irrigation water required to meet the demands in is under the current conditions, 152.47 billion m³ in 2030 and 176.34 billion m³ in 2050. Currently, the amount of water allocated to the agricultural sector is 86 billion m³, which is more than the environmental capacity. To achieve a sustainable environment, the amount of water allocated to the agricultural sector must be reduced to 39 billion m³. If the environmental protection is included, the country's self-sufficiency rate in producing plant products from a water perspective will be 25.6% in 2030 and 22.1% in 2050. With a 25% reduction in loss/waste, the amount of water needed to produce the products in demand will be 140.28 billion m³ in 2030 and 162.18 billion m³ in 2050. However, the use of a plant-based diet can significantly reduce the amount of demand for agricultural products and subsequently the demand for water.