Scientists say meatless diets could reduce our water footprint by half

Three thousand liters of water – that's the amount needed to produce the food that every Briton eats every day. According to a new study on "water footprint" diets in Western Europe, conducted by the European Commission and published in Nature Sustainability.

The term "carbon footprint", which represents all CO₂ emissions associated with the manufacture or production of an article, has become commonplace in recent years. Similarly, the "water footprint" of food can be calculated using information on the amount of water required during cultivation and processing.

The authors of this new study, led by Davy Vanham, an EC scientist, first collected existing data on the water footprint of various foods and beverages. They then combined this with census information for regions in the UK, France and Germany, and knowledge of local eating habits, to calculate the amount of water used to feed people in each region and how that could be reduced. Given the record heat wave and drought that hit Europe in the summer of 2018, their prospects may have arrived just in time.

Of the three countries studied, the United Kingdom has the smallest average water footprint of 2,757 liters per person per day, in Germany the average is 2,929 liters and in France, 3,861 (for reference, the US United use more than 9,000 liters per day). One of the most striking reasons for the difference between these countries is that the French drink more wine, compared to Germans and Britons who prefer beer, which has a lower water footprint.

Another feature of this study is the focus on small areas, which reveal great differences within these countries. A common theme is that rural areas have higher water footprints than cities, mainly because of differences in diet. Londoners, for example, eat less red meat than other regions. That's why the biggest footprints of the UK (even less than the smallest footprint in France) are found in South West, North Yorkshire and Lincolnshire.

In Germany and France, this trend is manifested by a distinct north-south division, the southwestern French wine regions using up to 5,000 liters per person per day. According to the study, the composition of regional populations is another cause of differences within each country. In London, the amount of wine consumed is closely related to the level of education of the residents. In other words, the water footprint increases with education.

But what does all this mean? Well, 3,000 liters a day represent more than a million liters a year – or enough water to fill your pool three times. More importantly, a higher water footprint is associated with an unhealthy diet, largely because meat requires much more water than vegetables or fruits. In the three countries, people "eat too much sugar, oils and fats, meat (red) as well as milk and cheese," write Vanham and his colleagues and in France and Germany, "people do not do not eat enough fruits and vegetables.

Eating less meat by adopting a "healthy meat" diet could reduce the water footprint by up to 35%, according to the authors. An even larger saving can be achieved if the meat is replaced by fish, which reduces the water footprint by 55%, but it is interesting to note that switching to a vegetarian diet involves the same savings. Making such changes will not only save water, but will also have the benefit of improving the diet in countries where more than a third of people have a problem. overweight and about a quarter are obese.

Convincing people to make such a change in their eating habits will not be easy. A number of suggestions were made in the study, including punitive measures for "unhealthy" foods, such as the sugar tax. However, such approaches are controversial, with considerable evidence suggesting that they are harmful for low-income families. A more subtle approach would be to change the layout of supermarkets, pushing consumers to healthier shopping.

Finally, the authors acknowledge that education of the population in food will be essential. But, as their own analysis shows, more education is associated with higher wine consumption, which increases the water footprint.