We are What We Eat: Tapping into Wisdom about Our Water Footprints

There’s a lot of debate about how much water we really need for good health. However, without mincing words, the amount of carbon dioxide we exhale, combined with how much we sweat, urinate, and defecate, dictates our daily water needs. Still stumped? Even with that helpful clue about how much liquid we need to renew, it’s not easy to measure daily water intake.Now, a new food calculator that provides a comprehensive water footprint for each meal we consume has been developed by scientists at Sustain in Bristol, England.

A water footprint represents the total volume of water required to produce the items used or consumed by nations. Unlike other food calculators currently available, Sustain's calculator allows users to enter the weight of their food choices, as well as specify the country of origin (UK or global)—and then calculates an accurate measure of water content.

Craig Jones, principal associate of Sustain, led the development of the calculator—based on the idea that consumers need to know much more than the footprint of a single food item. "We realized that, although there are a variety of water footprint food calculators available, not one calculates the footprint of an entire meal recipe," he said, adding, "Our calculator allows consumers to determine the water footprint of a Sunday roast dinner, or a portion of meat lasagna, and takes into account the ingredients' country of origin. By doing so, the calculator will help people see where they can make changes to their diet."

The company believes that the term, carbon footprint, is now commonly used and widely understood, but that individuals and industry don’t pay enough attention to their water footprints. Not only do we need adequate freshwater for our daily dietary intake, hygiene, and for nearly every industry; but, with changing weather patterns, waste of freshwater is just as harmful as carbon overproduction.

Indeed, the primary focus of Sustain’s work is water footprinting. Last October, the company received nearly £80,000 (US$121,000) of funding from the Technology Strategy Board (TSB) to develop the UK's first water footprint database for materials.

According to Sustain, the true UK water footprint is deceptive because the nation’s domestic consumption of water only covers 38 percent of its total footprint. The remaining 62 percent is consumed in countries around the world used in the supply chain for goods consumed in the UK— such as imported food, clothes and materials.

Jones envisions the footprint database as the starting point for recognizing and dealing with issues of water security. He said, "This database will be key in the development of successful water management strategies for businesses and government bodies alike. To date, not enough is being done and this database will show companies where the risks lie within their supply chains, in order to manage the problem more efficiently."

Environment Agency analysis has shown that in 2012 the UK experienced drought one in every four days and could experience a severe short-term drought every 10 years. According to the modeling, within the next 40 years, some river flows could be reduced by up to 80 percent during the summer—putting pressure on water availability for people, businesses and farmers.

The implications of a high water footprint are vast: Average household water use in the UK is around 150 liters (40 gallons) per person per day, but UK consumption of products from other countries means that each English citizen effectively uses around 4,645 liters (1,227 gallons) of the world's water every day.

Water scarcity is now a fast-growing sustainability problem across the world, with the amount used to produce an item far greater than the water contained within it. For example, the production of one kilogram of beef requires 15,400 liters (4,068 gallons) of water. In order to understand how to reduce our use of water, we need to measure this "embedded" or "virtual" water.

Download the calculator here. "