The impact of our diet that we never notice: it takes 21 liters of water to produce a chocolate bar
The food we eat can have a great environmental impact. Greenhouse gas emissions from food production and transportation is a topic that has been heavily scrutinized, but have you ever wondered what impact your favorite foods have on water scarcity? The answer may surprise you.
In research recently published in the academic journal Nutrients we analyzed the impact of water scarcity on the diets of 9,341 Australian adults, including more than 5,000 foods. We have measured both the amount of water used in the production of a food and the scarcity or abundance of water at the place of its collection.
The food system accounts for about 70% of fresh water use worldwide, which means that a joint effort to minimize water use in food production (ensuring that our diets remain healthy) would have a very important impact on Australia, the driest inhabited continent on the planet.
Cookies, beer or beef: What food needs more water for its production?
We concluded that the diet of the average Australian had an impact on water scarcity of 362 liters per day and that it was slightly less for women and adults over 71 years of age.
25% of the impact on water scarcity came from optional foods and beverages in our nutrition
The impact on water scarcity consists of two elements: the liters of water used multiplied according to whether the scarcity of water in the place of its collection is greater or less than the global average.
Some of the foods with some of the greatest impacts on water scarcity were almonds (3,448 liters per kilo), dried apricots (3,363 liters per kilo) and puffed rice-based breakfast cereals (1,464 liters per kilo) .
On the other hand, among some of the foods with the least impact on water scarcity were whole wheat bread (11.3 liters per kilo), rolled oats (23.4 liters per kilo) and canned chickpeas (5 , 9 liters per kilo).
It may surprise you to learn that of the 9,000 diets analyzed, 25% of the impact on water scarcity came from optional foods and beverages in our nutrition, such as cakes, cookies, sweetened beverages, and alcohol. The diets analyzed included a glass of wine (41 liters), an individual serving of French fries (23 liters) and a milk chocolate bar (21 liters).
This type of food not only makes us fat, but also has a negative impact on water scarcity. Previous studies have also shown that this type of food accounts for about 30% of the greenhouse gas emissions related to food consumption in Australia.
The second food group with the largest impact on water scarcity was fruit, at 19%. This category includes both whole fruits and fresh juices (not sweetened ones). Also keep in mind that fruit is an essential part of a healthy diet and that Australians generally need to consume more fruit to meet the recommended amounts.
Dairy products and their alternatives (including vegetable drinks based on soy, rice and nuts) were the third group and bread and cereals the fourth.
The consumption of red meat (beef and lamb) contributed only 3.7% of the total impact of food on water scarcity. These results suggest that consumption of fresh meat matters less in terms of water scarcity than most other food groups, including cereals.
How to reduce the use of water in your diet
Not surprisingly, a reduction in optional foods would be the first option to consider if you wanted to reduce your personal impact on water scarcity based on the foods you eat, as well as the greenhouse gas emissions associated with its production.
The consumerism of optional foods is also closely related to gaining weight and obesity. The varied consumption of healthy foods, according to our energy needs, is a good slogan to follow.
Two slices of whole wheat bread have a much lower impact on water scarcity than a cup of cooked rice
On the other hand, it is difficult to give recommendations that are relevant to consumers. We found that the variation in the impact on water scarcity of different foods within the same group was very high compared to the variation between different food groups.
For example, a medium-sized apple accounted for three liters for the water shortage impact compared to more than 100 liters for a 250 ml glass of fresh orange juice. This highlights the relative use of crop water and local water scarcity during the cultivation of these crops. It also takes more fruit to produce juice than when the fruit is consumed whole.
Two slices of whole wheat bread have a much lower impact on water scarcity than a cup of cooked rice (0.9 liters compared to 124 liters). One of the main sources of protein, lamb, had the least impact on water scarcity per serving (5.5 liters). Lambs are rarely raised on cultivated pastures and when harvest crops are used for their food, they are rarely irrigated crops.
In general, consumers do not have the necessary information to choose the main foods that have a low impact on water scarcity. To this must be added that diversity is an important principle in good nutrition and discouraging the consumption of a particular major food group could have adverse health consequences.
The best way to reduce the impact on water scarcity may be through technological changes
Perhaps the best opportunities for reducing the impact of water scarcity on the Australian food system lie with food production. Normally there is a great difference between producers in terms of the impact they have on water scarcity with similar agricultural productions.
For example, a study on the impact of water scarcity on tomato production for the supply of the city of Sydney presented results ranging from 5.0 to 52.8 liters of water per kilo. The differences in the impact on water scarcity of milk produced in the Australian state of Victoria ranged from 0.7 liters to 262 liters, something that highlights the differences between agricultural methods with differences in the use of irrigation and at local levels of water scarcity.
The best way to reduce the impact on water scarcity may be through technological change, product reformulation and the acquisition of new strategies in the agriculture and food production industries.
Not all water is the same
This is the first study of its kind to analyze the impact on water scarcity of a large number of diets chosen individually by each person.
It has not been an easy task, considering that 5,645 different foods were identified, many of which were processed foods whose analysis required their separation between their individual ingredients.
It is difficult to say to what extent these results can be compared with those of other countries, since the same analysis has not been carried out elsewhere. This study has shown large differences in the impact on water scarcity of the way Australians consume food, reflecting the variety of our eating habits.
Water scarcity is only one of the relevant environmental aspects in food production and consumption. While we are not suggesting that dietary guidelines need to be changed in relation to their impact on water scarcity, we hope that this research will encourage more sustainable food production and consumption.
Authors: Brad Ridoutt, Danielle Baird, Gilly Hendrie, and Kimberley Anastasiou from the Commonwealth Scientific and Industrial Research Organization (CSIRO)
This article was originally published on The Conversation. You can read the original article here.
Translated by Silvestre Urbón.
The author of the original text reported that he had conducted research for the government organization Meat and Livestock Australia. It should be noted that the research that the text deals with is one of the projects funded by the Meat and Livestock Australia organization.