Water is becoming an increasing scarce resource. Meanwhile, a small chocolate bar requires 21 litres of water to produce. A glass of wine requires 41 litres and a single serve of potato crisps 23 litres. When you add it all up, that’s a lot of H2O!
It’s time we all attempted to reduce water use in our diets. Here are some tips.
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).
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.