.

  • Written by Brad Ridoutt, Principal Research Scientist, CSIRO Agriculture, CSIRO
A small chocolate bar takes 21 litres of water to produce. Byline: CAROLINE BLUMBERG/ EPA

Our diets can have a big environmental impact. The greenhouse gas emissions involved in producing and transporting various foods has been well researched, but have you ever thought about the water-scarcity impacts of producing your favourite foods? The answers may surprise you.

In research recently published in the journal Nutrients, we looked at the water scarcity footprints of the diets of 9,341 adult Australians, involving more than 5,000 foods. We measured both the amount of water used to produce a food, and whether water was scarce or abundant at the location it was drawn from.

The food system accounts for around 70% of global freshwater use. This means a concerted effort to minimise the water used to produce our food - while ensuring our diets remained healthy - would have a big impact in Australia, the driest inhabited continent on Earth.

Biscuits, beer or beef: which takes the most water to produce?

We found the average Australian’s diet had a water-scarcity footprint of 362 litres per day. It was slightly lower for women and lower for adults over 71 years of age.

A water-scarcity footprint consists of two elements: the litres of water used, multiplied by a weighting depending on whether water scarcity at the source is higher or lower than the global average.

Foods with some of the highest water-scarcity footprints were almonds (3,448 litres/kg), dried apricots (3,363 litres/kg) and breakfast cereal made from puffed rice (1,464 litres/kg).

In contrast, foods with some of the smallest water-scarcity footprint included wholemeal bread (11.3 litres/kg), oats (23.4 litres/kg), and soaked chickpeas (5.9 litres/kg).


Read more: What's made of legumes but sizzles on the barbie like beef? Australia's new high-tech meat alternative


It may surprise you that of the 9,000 diets studied, 25% of the water scarcity footprint came from discretionary foods and beverages such as cakes, biscuits, sugar-sweetened drinks and alcohol. They included a glass of wine (41 litres), a single serve of potato crisps (23 litres), and a small bar of milk chocolate (21 litres).

These foods don’t only add to our waistlines, but also our water-scarcity footprint. Previous studies have also shown these foods contribute around 30% of dietary greenhouse gas emissions in Australia.

Sheep drink from a dried-up water storage canal between Pooncarie and Menindee in western NSW. Water shortages along the Murray Darling Basin have devastated ecosystems and communities. Dean Lewins/AAP

The second highest food group in terms of contributing to water-scarcity was fruit, at 19%. This includes whole fruit and fresh (not sugar-sweetened) juices. It should be remembered that fruit is an essential part of a healthy diet, and generally Australians need to consume more fruit to meet recommendations.

Dairy products and alternatives (including non-dairy beverages made from soy, rice and nuts) came in third and bread and cereals ranked fourth.

The consumption of red meat - beef and lamb - contributed only 3.7% of the total dietary water-scarcity footprint. These results suggest that eating fresh meat is less important to water scarcity than most other food groups, even cereals.

How to reduce water use in your diet

Not surprisingly, cutting out discretionary foods would be number one priority if you wanted to lower the water footprint of the food you eat, as well as the greenhouse gas emissions of production.

Over-consumption of discretionary foods is also closely linked to weight gain and obesity. Eating a variety of healthy foods, according to energy needs, is a helpful motto.

Aside from this, it is difficult to give recommendations that are relevant to consumers. We found that the variation in water-scarcity footprint of different foods within a food group was very high compared to the variation between food groups.


Read more: Curious Kids: why can't we just build a pipe to move water to areas in drought?


For example, a medium sized apple was found to contribute a water-scarcity footprint of three litres compared with more than 100 litres for a 250 ml glass of fresh orange juice. This reflects the relative use of irrigation water and the local water scarcity where these crops are grown. It also takes more fruit to produce juice than when fruit is consumed whole.

Two slices of wholegrain bread had a much lower water-scarcity footprint than a cup of cooked rice (0.9 litres compared with 124 litres). Of the main protein sources, lamb had the lowest water-scarcity footprint per serve (5.5 litres). Lambs are rarely raised on irrigated pastures and when crops are used for feeding, these are similarly rarely irrigated.

Consumers generally lack the information they would need to choose core foods with a lower water-scarcity footprint. Added to this, diversity is an important principle of good nutrition and dissuading consumption of particular core foods could have adverse consequences for health.

Workers process punnets of strawberries at a Queensland strawberry farm. Dan Peled/AAP

Perhaps the best opportunities to reduce water scarcity impacts in the Australian food system lie in food production. There is often very large variation between producers in water scarcity footprint of the same farm commodity.

For example, a study of the water scarcity footprint of tomatoes grown for the Sydney market reported results ranging from 5.0 to 52.8 litres per kg. Variation in the water-scarcity footprint of milk produced in Victoria was reported to range from 0.7 to 262 litres. This mainly reflects differences in farming methods, with variation in the use of irrigation and also the local water scarcity level.

Water-scarcity footprint reductions could best be achieved through technological change, product reformulation and procurement strategies in agriculture and food industries.

Not all water is equal

This is the first study of its kind to report the water-scarcity footprint for a large number of individual self-selected diets.

This was no small task, given that 5,645 individual foods were identified. Many were processed foods which needed to be separated into their component ingredients.


Read more: Climate explained: what each of us can do to reduce our carbon footprint


It’s hard to say how these results compare to other countries as the same analysis has not been done elsewhere. The study did show a large variation in water-scarcity footprints within Australian diets, reflecting the diversity of our eating habits.

Water scarcity is just one important environmental aspects of food production and consumption. While we don’t suggest that dietary guidelines be amended based on water scarcity footprints, we hope this research will support more sustainable production and consumption of food.

Brad Ridoutt has undertaken food systems research related to environmental issues for a variety of private sector organizations and Australian government agencies. This includes Meat and Livestock Australia and Dairy Australia

Authors: Brad Ridoutt, Principal Research Scientist, CSIRO Agriculture, CSIRO

Read more http://theconversation.com/it-takes-21-litres-of-water-to-produce-a-small-chocolate-bar-how-water-wise-is-your-diet-123180

Is your horse normal? Now there’s an app for that

Vet: are you happy? Horse: neigh. evilgurl/Flickr, CC BY-NC-SASince ancient times, horse behaviour, and the bond between horses and humans, has been a source of intrigue and fascination. The horse-l...

Paul McGreevy, Professor of Animal Behaviour and Animal Welfare Science, University of Sydney - avatar Paul McGreevy, Professor of Animal Behaviour and Animal Welfare Science, University of Sydney

Small histories: a road trip reveals local museums stuck in a rut

Berry, and other tourist towns, are out of step with modern museum curation which is trying to include Aboriginal communities and their stories. ShutterstockAboriginal and Torres Strait Islander read...

Jen Saunders, Phd candidate, University of Wollongong - avatar Jen Saunders, Phd candidate, University of Wollongong

Curious Kids: how are stars made?

Stars come into existence because of a powerful force of nature called gravity. ESA/Hubble & NASA, Acknowledgement: Judy SchmidtIf you have a question you’d like an expert to answer, send it...

Orsola De Marco, Astrophysicist , Macquarie University - avatar Orsola De Marco, Astrophysicist , Macquarie University

What is perimenopause and how does it affect women's health in midlife?

Perimenopause lasts months for some women, and years for others. from www.shutterstock.comAll women know to expect the time in life when their periods finish and they reach menopause. Many might even...

Gita Mishra, Professor of Life Course Epidemiology, Faculty of Medicine, The University of Queensland - avatar Gita Mishra, Professor of Life Course Epidemiology, Faculty of Medicine, The University of Queensland

Vital signs. Our compulsory super system is broken. We ought to axe it, or completely reform it

We're taking money from people, letting it fall through the cracks, and spending no less than we were on pensions. ShutterstockThe just-announced inquiry into Australia’s retirement income syste...

Richard Holden, Professor of Economics, UNSW - avatar Richard Holden, Professor of Economics, UNSW

Might consciousness and free will be the aces up our sleeves when it comes to competing with robots?

Our advantage lies in incommensurables, and it'll grow in importance. Franck V. on UnsplashThe rise of artificial intelligence has led to widespread concern about the role of humans in the workplaces ...

Allan McCay, Law Lecturer, University of Sydney - avatar Allan McCay, Law Lecturer, University of Sydney

Should I stay or should I go: how 'city girls' can learn to feel at home in the country

Shutterstock/The ConversationA move to the country is often presented in popular culture as an idyllic life, a place where you can escape the pressures of the city. It’s in television shows su...

Rachael Wallis, Lecturer and Honorary Research Fellow, University of Southern Queensland - avatar Rachael Wallis, Lecturer and Honorary Research Fellow, University of Southern Queensland

Grattan on Friday: Storm clouds avoid the bush, darken over the economy

National Farmers' Federation president Fiona Simson says she doesn't think the government has a drought policy. ShutterstockGovernment sources insist shock jock Alan Jones didn’t drive Thursday&...

Michelle Grattan, Professorial Fellow, University of Canberra - avatar Michelle Grattan, Professorial Fellow, University of Canberra

Julianne Schultz appointed chair of The Conversation

Professor Julianne Schultz AM FAMA has been appointed chair of The Conversation Media Group, following the retirement of Harrison Young. Since becoming chairman in April 2017, Harrison has improved ...

Misha Ketchell, Editor & Executive Director, The Conversation - avatar Misha Ketchell, Editor & Executive Director, The Conversation

Cats are not scared off by dingoes. We must find another way to protect native animals

New research suggests feral cats can probably outsmart dingoes. Wikimedia/AAPFeral cats are wreaking havoc on our native wildlife, eating more than a billion animals across Australia every year. But ...

Bronwyn Fancourt, Adjunct Research Fellow, University of New England - avatar Bronwyn Fancourt, Adjunct Research Fellow, University of New England

Curious Kids: does chewing gum stay inside you for years?

Swallowing a lot of gum can cause it to stick together or stick to food in your gut. www.shuttershock.com, CC BYIf you have a question you’d like an expert to answer, send it to curiouskids@th...

Jerry Zhou, Lecturer, School of Medicine, Western Sydney University - avatar Jerry Zhou, Lecturer, School of Medicine, Western Sydney University

Don't believe your ears: 'enhancing' forensic audio can mislead juries in criminal trials

Audio used as evidence in criminal trials can often be unreliable.  Many criminal trials feature forensic evidence in the form of audio recordings, typically from bugging houses or cars, or intercep...

Helen Fraser, Adjunct Associate Professor, University of New England - avatar Helen Fraser, Adjunct Associate Professor, University of New England

The case for 'inclusion riders' in creative industries: what Australian discrimination law says about quotas

In March last year, Frances McDormand won the Academy Award for Best Actress. In her acceptance speech, she drew attention to the female nominees in the room and left them with two final words: &ldq...

Liam Elphick, Adjunct Research Fellow, Law School, University of Western Australia - avatar Liam Elphick, Adjunct Research Fellow, Law School, University of Western Australia

The Portal review: can meditation change the world?

The Portal uses individual stories of meditative transformation to suggest a bigger change is possible. SuppliedThe Portal follows six individuals who undergo a personal transformation from trauma an...

Peggy Kern, Associate professor, University of Melbourne - avatar Peggy Kern, Associate professor, University of Melbourne

Why white married women are more likely to vote for conservative parties

Women’s perceptions of 'gender linked fate' were contingent on two dimensions: their race and their marital status. ShutterstockThe polls were wrong in the last US and Australian federal electi...

Leah Ruppanner, Associate Professor in Sociology and Co-Director of The Policy Lab, University of Melbourne - avatar Leah Ruppanner, Associate Professor in Sociology and Co-Director of The Policy Lab, University of Melbourne

Thoughts and prayers: miracles, Christianity and praying for rain

In a speech in Albury last month, Prime Minister Scott Morrison told his audience that he was praying for rain in drought-affected areas. “I pray for that rain everywhere else around the count...

Philip C. Almond, Emeritus Professor in the History of Religious Thought, The University of Queensland - avatar Philip C. Almond, Emeritus Professor in the History of Religious Thought, The University of Queensland

Prime Minister's science prizes awarded for algebra expertise, anti-cancer research and excellence in science teaching

Cheryl Praeger was awarded the 2019 Prime Minister’s Prizes for Science. She has spent more than four decades inspiring a love for maths in others, and has created a vast body of academic work i...

Michael Hopkin, Science + Technology Editor, The Conversation - avatar Michael Hopkin, Science + Technology Editor, The Conversation

Curious Kids: is it OK to listen to music while studying?

Does music usually put you in a better mood? That might help you try a little bit harder and stick with challenging tasks. Shutterstock I am in year 11 and I like to listen to music when I am studyin...

Timothy Byron, Lecturer in Psychology, University of Wollongong - avatar Timothy Byron, Lecturer in Psychology, University of Wollongong

A requiem for Reformasi as Joko Widodo unravels Indonesia's democratic legacy

It’s deeply ironic that Indonesia’s third president, BJ Habibie, died on September 11 – less than a week before the national legislature passed a law that gutted the highly-regarded ...

Tim Lindsey, Malcolm Smith Professor of Asian Law and Director of the Centre for Indonesian Law, Islam and Society, University of Melbourne - avatar Tim Lindsey, Malcolm Smith Professor of Asian Law and Director of the Centre for Indonesian Law, Islam and Society, University of Melbourne

Sick and Tired of Your Dead End Job? Try Teaching!

Tired of the same old grind at the office? Want an opportunity to impact lives both in your community and around the world? Do you love to travel and have new experiences? Teaching English is the perfect job for you! All you need is a willingness to ...

News Company - avatar News Company

The Impact of an Aging Population in Australia

There’s an issue on the horizon that Australia needs to prepare for. The portion of elderly citizens that make up the country’s overall population is increasing, and we might not have the infrastructure in place to support this. Australians h...

News Company - avatar News Company

LifeStyle

Questions to ask yourself before buying your watch

There are more and more watches on the market. And more and more brands are trying to seduce consu...

How to Thoroughly Prepare Children for a Professional Photoshoot at a Studio

Children are only young for a moment, which is why, for a lot of parents, it's essential to take a...

What to Expect at the University of Florida Tour

The University of Florida is a dream college for most aspiring students. Not only because of its p...

7 Professions that Will Be Huge in the Next Decade

In order to embark on a career path that requires a lot of training and experience, you might ne...