The water footprints related to food consumption in the United Kingdom, France, and Germany are reported in a paper published online this week in Nature Sustainability. Taking into account the socio-economic factors of food consumption for both current and recommended diets, these numbers suggest that vegetarian and pescatarian diets could reduce a society’s water footprint by up to half through the substitution of crops in place of meat, which takes a lot of water to produce. However, substantial savings could also be made through healthy diets in which less meat is eaten.

The water-footprint concept has been recognized as being highly valuable for raising awareness of the large quantity of water resources required to produce the food we consume. Although general water consumption has become a major issue, the water that we ‘eat’ has not come under the same scrutiny. However, everyday diets can consume vast quantities of water, with variations depending on culture and geography.

Davy Vanham and colleagues measure the water used for the production of food consumed in 44,000 of the smallest administrative units (such as districts or municipalities) across the UK, France and Germany. They find that switching to a healthy meat diet would reduce each area’s total water footprint by 11-35% - while pescatarian and vegetarian diets would reduce footprints by 33-55% - depending on regional differences in the consumption of products such as meat, oils, milk, wine, fruits and fish.