22/03/2013 13:43 GMT | Updated 22/05/2013 06:12 BST

Food, Glorious Food!

Friday is World Water Day, and with that in mind we, at Sustain, have developed the UK's most comprehensive food calculator that gives a comprehensive water footprint of a full meal.

Unlike other food calculators currently available, ours allows the input of weight of the food item as well as specifying the country of origin as UK or global, giving the most accurate measure ever of the water footprint of a full meal.

We believe that if the importance of water footprinting as a world issue was to increase, then consumers need to know much more than the footprint of a single food item.

Sustain is one of the UK's leading sustainability companies and a primary focus of our work is water footprinting. Its creation is linked to our work for the Technology Strategy Board (TSB), developing the UK's first water footprint database and we realised that although there are a variety of water footprint food calculators available, not one calculates the footprint of an entire meal recipe.

The term carbon footprint is now commonly used and widely understood, but a water footprint has, to a large extent, played something of a forgotten role as an input to the commodities we consume. A water footprint is the total volume of water that is used to produce the items used or consumed by nations.

Our calculator allows consumers to determine the water footprint of a Sunday roast dinner, or a portion of meat lasagne, 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 - and weekly shop - to decrease their water footprint easily and effectively.

The implications of a high water footprint are vast: average household water use in the UK is around 150 litres per person per day, but UK consumption of products from other countries means that each English citizen effectively uses around 4,645 litres 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, a small latte needs 710 litres of water to produce while the production of one kilogram of beef requires 15,400 litres of water. In order to understand how to reduce our use of water, we need to measure this "embedded" or "virtual" water.

Our aim is to make the term 'water footprint' as well known, and as well understood, as the term 'carbon footprint', and at the same time raise awareness of this vital issue so that UK residents can reduce their water footprint as quickly and as simply as possible. By using the calculator, available to download from our website , everyone can work out the water footprint of virtually any meal and gain a better understanding of the sheer volume of water necessary in our everyday habits.