By now the whole country has heard about the severe drought situation in California. As a farmer, I am acutely aware of the water shortage and how it is affecting agriculture. As a dietitian, I wonder about the recommendations I make to eat a healthier Mediterranean diet and how that might impact the “water footprint” of a typical Californian’s diet.
California agriculture uses 80 percent of all the developed water in California after subtracting out environmental diversion. That sounds like a lot until we realize that over 90 percent of the typical California resident’s water footprint is associated with agricultural products of various types. Admittedly some of this is water imbedded in imported products so the actual impact on California is hard to estimate. California farmers have not increased net water use in 30 years, while the value of products produced in that time period has almost doubled. They will now be asked to do even more with less. California produces over 50 percent of the fruits and vegetables eaten in the U.S. Hopefully reducing California farm water use will not lead to less healthy food available for all Americans.
The average Californian has a water footprint of 1500 gallons per day, most of it associated with the production of the products we use including food, clothing, housing, transportation, and consumer goods. Reducing household water use only scratches the surface as the average California per capita household use is around 140 gallons per day.
Animal agriculture has been a target in the media, and the water footprint of cattle admittedly is large. However one cannot just subtract animal foods off the diet and then re-calculate the footprint. Substitutions must be made to meet protein and calorie needs.
The Mediterranean diet is a predominantly plant based diet that still includes animal protein foods and has been recognized as one of the healthiest traditional food patterns. California has a Mediterranean climate, marked by wet winters (usually) and dry summers. A traditional Mediterranean Diet by environmental necessity should focus on dietary sources of nutrients, including protein, that are lower in water intensity.
In the calculations below, I compare the water footprint of a California Mediterranean Diet with that of a typical American Diet. Recommendations for entire food group changes to calculate impacts were used. Water use by specific varieties of food grown (i.e. lower water intensity types of fruits and vegetables etc.) were not calculated but an aggregate switch from a typical current American Diet to a proposed Mediterranean Diet of equal nutritional value was used to calculate water footprint impacts. At the bottom of this post, see links to the various resources I used to develop this comparison.
Typical American Daily Diet , selected nutrients and calculated water footprint per day
|Food product||Amount eaten in ounces||Calories provided in amount eaten||Protein provided in amount eaten||Liters of water to produce one ounce||Total water to produce amount eaten|
|Daily Total||2427||80.9||2649 liters/ 700 gallons|
A Recommended California Mediterranean Daily Diet, selected nutrients and calculated water footprint per day
|Food product||Amount in ounces recommended||Calories in amount recommended||Protein in amount recommended||Liters of water to produce one ounce||Total water to produce amount eaten|
|Daily Total||2444||84.6||2097 liters/ 554 gallons|
Switching from a typical unhealthy American Diet to a healthier Mediterranean Diet should reduce the water footprint of your diet by 146 gallons per day or 20 percent. This is just about the typical California household water use per individual of 140 gallons per day and 9 percent of the total water footprint of a typical Californian.
If you would like to switch to a California Mediterranean Diet, this link will break down the recommendations into amounts of foods that you might typically eat. The California Mediterranean Diet
Just a quick note on other ways to reduce the water footprint of your diet:
If you are overweight, eat less: 2/3 of Americans are overweight. Reducing daily calorie intake by reducing overall food consumption will reduce the water footprint of the American diet.
Reduce food waste: The total food waste in the US is a whopping 40 percent of the food that is produced. The typical family throws out over 1/4 of all the food that they purchase. Water is used to produce that wasted food so reducing food waste can further reduce your water footprint.
Here is a link to an article about a cool little app the USDA has developed to help you reduce food waste:
Here are some of the resources I used to develop the above tables:
Water references http://www.google.com/url?sa=t&rct=j&q=&esrc=s&source=web&cd=1&ved=0CB8QFjAA&url=http%3A%2F%2Fwww.waterfootprint.org%2FReports%2FHoekstra-2012-Water-Meat-Dairy.pdf&ei=zUcsVY-aBsipogS9_IHYAQ&usg=AFQjCNEflBQO7Zbna4MqQ2USxr9HFzgbYA&bvm=bv.90790515,d.cGU
Food composition data
CDC obesity Data