Our diets can have a giant environmental impression. The greenhouse fuel emissions concerned in producing and transporting varied meals has been nicely researched, however have you ever ever thought in regards to the water-scarcity impacts of manufacturing your favorite meals? The solutions might shock you.
In analysis just lately revealed within the journal Vitamins, we regarded on the water shortage footprints of the diets of 9,341 grownup Australians, involving greater than 5,000 meals. We measured each the quantity of water used to supply a meals, and whether or not water was scarce or ample on the location it was drawn from.
The meals system accounts for round 70 p.c of world freshwater use. This implies a concerted effort to minimise the water used to supply our meals – whereas making certain our diets remained wholesome – would have a huge impact in Australia, the driest inhabited continent on Earth.
Biscuits, beer or beef: which takes essentially the most water to supply?
We discovered the common Australian’s food plan had a water-scarcity footprint of 362 litres per day. It was barely decrease for ladies and decrease for adults over 71 years of age.
A water-scarcity footprint consists of two parts: the litres of water used, multiplied by a weighting relying on whether or not water shortage on the supply is increased or decrease than the worldwide common.
Meals with a number of the highest water-scarcity footprints had been almonds (three,448 litres/kg), dried apricots (three,363 litres/kg) and breakfast cereal created from puffed rice (1,464 litres/kg).
In distinction, meals with a number of the smallest water-scarcity footprint included wholemeal bread (11.three litres/kg), oats (23.four litres/kg), and soaked chickpeas (5.9 litres/kg).
It might shock you that of the 9,000 diets studied, 25 p.c of the water shortage footprint got here from discretionary meals and drinks reminiscent of desserts, 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 meals do not solely add to our waistlines, but in addition our water-scarcity footprint. Earlier research have additionally proven these meals contribute round 30 p.c of dietary greenhouse fuel emissions in Australia.
The second highest meals group when it comes to contributing to water-scarcity was fruit, at 19 p.c. This consists of complete fruit and recent (not sugar-sweetened) juices. It must be remembered that fruit is a vital a part of a nutritious diet, and customarily Australians have to devour extra fruit to satisfy suggestions.
Dairy merchandise and alternate options (together with non-dairy drinks created from soy, rice and nuts) got here in third and bread and cereals ranked fourth.
The consumption of crimson meat – beef and lamb – contributed solely three.7 p.c of the full dietary water-scarcity footprint. These outcomes counsel that consuming recent meat is much less necessary to water shortage than most different meals teams, even cereals.
Learn how to cut back water use in your food plan
Not surprisingly, reducing out discretionary meals can be primary precedence in case you needed to decrease the water footprint of the meals you eat, in addition to the greenhouse fuel emissions of manufacturing.
Over-consumption of discretionary meals can also be carefully linked to weight achieve and weight problems. Consuming quite a lot of wholesome meals, in accordance with power wants, is a useful motto.
Apart from this, it’s tough to provide suggestions which might be related to shoppers. We discovered that the variation in water-scarcity footprint of various meals inside a meals group was very excessive in comparison with the variation between meals teams.
For instance, a medium sized apple was discovered to contribute a water-scarcity footprint of three litres in contrast with greater than 100 litres for a 250 ml glass of recent orange juice. This displays the relative use of irrigation water and the native water shortage the place these crops are grown. It additionally takes extra fruit to supply juice than when fruit is consumed complete.
Two slices of wholegrain bread had a a lot decrease water-scarcity footprint than a cup of cooked rice (zero.9 litres in contrast with 124 litres). Of the principle protein sources, lamb had the bottom water-scarcity footprint per serve (5.5 litres). Lambs are not often raised on irrigated pastures and when crops are used for feeding, these are equally not often irrigated.
Customers usually lack the knowledge they would want to decide on core meals with a decrease water-scarcity footprint. Added to this, variety is a vital precept of excellent diet and dissuading consumption of specific core meals may have adversarial penalties for well being.
Maybe the most effective alternatives to cut back water shortage impacts within the Australian meals system lie in meals manufacturing. There’s usually very massive variation between producers in water shortage footprint of the identical farm commodity.
For instance, a examine of the water shortage footprint of tomatoes grown for the Sydney market reported outcomes starting from 5.zero to 52.eight litres per kg. Variation within the water-scarcity footprint of milk produced in Victoria was reported to vary from zero.7 to 262 litres. This primarily displays variations in farming strategies, with variation in using irrigation and in addition the native water shortage stage.
Water-scarcity footprint reductions may greatest be achieved by means of technological change, product reformulation and procurement methods in agriculture and meals industries.
Not all water is equal
That is the primary examine of its form to report the water-scarcity footprint for a lot of particular person self-selected diets.
This was no small activity, provided that 5,645 particular person meals had been recognized. Many had been processed meals which wanted to be separated into their part components.
It is exhausting to say how these outcomes examine to different nations as the identical evaluation has not been performed elsewhere. The examine did present a big variation in water-scarcity footprints inside Australian diets, reflecting the variety of our consuming habits.
Water shortage is only one necessary environmental elements of meals manufacturing and consumption. Whereas we do not counsel that dietary tips be amended based mostly on water shortage footprints, we hope this analysis will help extra sustainable manufacturing and consumption of meals.
Brad Ridoutt, Principal Analysis Scientist, CSIRO Agriculture, CSIRO.
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