The impact of nutrient-rich food choices on agricultural water-use efficiency

When distributed equally, the total amount of food produced worldwide could sufficiently meet current global demand. Still, malnutrition in the form of nutrient deficiencies continues to prevail in both low- and high-income countries. At the same time, natural resource use for agriculture is reaching or exceeding environmental boundaries. By integrating a comprehensive micronutrient scoring method with data on agricultural water demand, this analysis aims to re-evaluate the global water-use efficiency of dietary nutrient production. A stronger reliance on more nutrient-dense foods could lead to higher water-use efficiencies, though dietary water footprints were likely to increase overall. With a more detailed focus on plant and animal foods, we find that most dietary protein sources show comparable water-use efficiencies, and thus can be drivers for agricultural water demand. Animal foods, besides having a unique nutrient profile, often do not compete directly with crops for the same water resources. However, a significant reduction in the demand for utilizable freshwater resources could be achieved by reducing the amount of feed crops in ruminant diets.