Meat-free diets could cut our 'water footprint' in half, say scientists

September 11, 2018 by Ben Keane, The Conversation
Vines won’t water themselves. Credit: NF Photography/Shutterstock

Three thousand litres of water – that is the amount needed to produce the food each British person eats every day. This is according to a new study into the "water footprint" of diets in Western Europe, conducted by the European Commission and published in Nature Sustainability.

The term "carbon footprint", which accounts for all the emissions of CO₂ associated with the manufacture or production of an item, has become commonplace in recent years. Similarly, the " 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 EC scientist Davy Vanham, first gathered existing data on the water footprint of various foods and drinks. They then combined this with census information for regions within the UK, France and Germany, and knowledge of local , to calculate how much water is used to feed people in each region and how that could be reduced. Considering the record-breaking heatwave and drought across Europe in summer 2018, their insight may have arrived just in time.

Of the three countries studied, the UK has the smallest average water footprint at 2,757 litres per person per day, in Germany the average is 2,929 and in France it's 3,861 (for reference, people in the US use more than 9,000 litres per day). One of the standout reasons for the difference between these countries is that the French drink more wine, compared to the Germans and the British who prefer beer, which has a smaller water footprint.

UK water footprint related to food consumption (litres per person per day). Credit: Vanham et al

Another feature of this study is the focus on smaller regions which reveals large differences within these countries. A common theme is that rural areas have higher water footprints than cities, mainly due to differences in diet. People in London, for example, eat less than other regions. This is why the UK's highest footprints (still less than France's smallest footprint) are found in the south-west, North Yorkshire and Lincolnshire.

In Germany and France this trend manifests as a distinct north-south divide, with the French wine growing regions in the south-west using up to 5,000 litres per person per day. According to the study, another cause of differences within each country is the make up of regional populations. In London, the amount of wine consumed is closely related to the level of education of residents. In other words, water footprint increases with education.

But what does all this mean? Well, 3,000 litres a day adds up to more than a million litres per year – or enough water to fill your local swimming pool three times over. More importantly, a higher water footprint is associated with an unhealthy diet, largely due to meat requiring a lot more water than vegetables or fruit. In all three countries, people "eat too much sugar, oils and fats, (red) meat as well as milk and cheese combined," write Vanham and colleagues, and in France and Germany "people do not eat enough fruit and vegetables."

Reduction in water footprint of food consumption, if everyone switched to a healthy diet still containing meat (Darkest blue = 90% or more reduction). Credit: Vanham et al

Eating less meat through adopting a "healthy meat" diet could reduce water footprint by up to 35%, the authors say. An even greater saving can be made if meat is replaced by fish, lowering water footprint by 55%, but interestingly moving completely to a vegetarian diet makes around the same savings. Making such changes will not only save water, but will have the additional benefit of improving diet in countries where more than a third of people are overweight and around a quarter obese.

Convincing people to make such a change to their eating habits will not be simple. A number of suggestions are put forward in the study, including punitive measures for "unhealthy" foods, such as a sugar tax. However, such approaches are controversial, with considerable evidence suggesting that they are harmful to low income families. A more subtle approach would be to change the layout of supermarkets, "nudging" shoppers towards more healthy purchases.

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

Explore further: Change your diet to save both water and your health

Related Stories

S.Africa's Cape Town eases water rationing

September 10, 2018

South Africa's second city Cape Town, battling its worst drought in 100 years, announced Monday that it would ease severe water rationing after significant rains in the region.

Calculating water footprints of animal, plant proteins

January 31, 2011

Many times more water is needed for the production of meat and other animal products, such as eggs and dairy produce, than for the production of plant products. The University of Twente (The Netherlands) has for the first ...

Fair sharing of water resources is key, says expert

March 22, 2018

To really do something about our massive overconsumption of water, we should limit the strain we put on rivers and freshwater basins. Information on the water use of our products should be transparent and clear. And in the ...

Recommended for you

A decade on, smartphone-like software finally heads to space

March 20, 2019

Once a traditional satellite is launched into space, its physical hardware and computer software stay mostly immutable for the rest of its existence as it orbits the Earth, even as the technology it serves on the ground continues ...

Tiny 'water bears' can teach us about survival

March 20, 2019

Earth's ultimate survivors can weather extreme heat, cold, radiation and even the vacuum of space. Now the U.S. military hopes these tiny critters called tardigrades can teach us about true toughness.

Researchers find hidden proteins in bacteria

March 20, 2019

Scientists at the University of Illinois at Chicago have developed a way to identify the beginning of every gene—known as a translation start site or a start codon—in bacterial cell DNA with a single experiment and, through ...


Adjust slider to filter visible comments by rank

Display comments: newest first

not rated yet Sep 11, 2018
What a terrible idea.
5 / 5 (1) Sep 11, 2018
Northern Europe is not really short of water
1 / 5 (1) Sep 11, 2018
Northern Europe is not really short of water

Tell that to german farmers. The drought (due to climate change) has killed about a third of the crops this year. (Don't even ask how the more southerly/mediterranean countries are doing)

Water use is a serious issue even in northerly regions. Aquifers are dropping to record lows year after year and the glaciers that are supplying the rivers with fresh water are vanishing.

Convincing people to make such a change to their eating habits will not be simple.

Or we get that lab-meat thing going. I'd be all for that.

Please sign in to add a comment. Registration is free, and takes less than a minute. Read more

Click here to reset your password.
Sign in to get notified via email when new comments are made.