As consumers increasingly aim to make environmentally responsible food purchases, they need to base their decision on sound science. However, according to a presenter at the recent Cornell Nutrition Conference in Syracuse, N.Y., the ‘intuitively correct’ food choice is often the least environmentally friendly option.

Jude Capper, assistant professor of dairy sciences at Washington State University, told the audience of animal nutrition specialists that, "as a food industry, we must use a whole-system approach and assess environmental impact per gallon of milk, pound of beef or dozen eggs, not per farm or per acre." This important distinction is the basis of a ‘life-cycle assessment’ approach, which evaluates all inputs and outputs within the food-production system, and allows us to correctly compare different production systems.

"Consumer demand for milk, meat and eggs is going to increase as the population continues to grow," Capper says. "Therefore, the vital role of improved productivity and efficiency in reducing environmental impact must be conveyed to government, food retailers and consumers."

Intuitively, today’s modern production practices often seem to have a higher environmental impact than the "idyllic" management practices of the 1940s. Nonetheless, when assessed on a whole-system basis, greenhouse gas emissions per gallon of milk produced are 63 percent lower. In 2007, the U.S. dairy industry produced 8.3 billion more gallons of milk than in 1944, but due to improved productivity, the carbon footprint of the entire dairy farm industry was reduced by 41 percent during the same time period.

Pasture- or grass-fed meat also is growing in popularity, with the perception that it is more eco-friendly than conventionally produced beef. However, the time needed to grow an animal to slaughter weight is nearly double that of animals fed corn. This means that energy use and greenhouse gas emissions per pound of beef are increased three-fold in grass-fed beef cattle. In total, finishing the current U.S. population of 9.8 million fed-cattle on pasture would require an extra 60 million acres of land. Again, the intuitively environmentally friendly option has a far higher resource and environmental cost.

Another emerging trend among American consumers is the desire to purchase food grown locally. "Often ‘locally grown’ food is thought to have a lower environmental impact than food transported over long distances due to carbon emissions from fuel," explains Capper. The phrase "Food Miles" has become a popular buzzword, defined simply as the distance that food travels from its place of origin to its place of final consumption.

"Although well-intentioned, it is incorrect to assume that the distance that food travels from point of origin to point of consumption is an accurate reflection of environmental impact," Capper says. "This simplistic approach fails to consider the productivity of the transportation system, which has tremendous impact on the energy expended per unit of food."

As an example, one dozen eggs, transported several hundred miles to a grocery store in a tractor-trailer that can carry 23,400 dozen eggs is a more fuel-efficient, eco-friendly option than a dozen eggs purchased at a farmers’ market (4.5 times more fuel used) or local farm (17.2 times more fuel used).

"The high-capacity vehicles used in modern transportation systems improve productivity, allowing food moved over long distances to be highly fuel-efficient and environmentally friendly compared to locally grown food," Capper explains.

The desire to protect the environment and to do so, in part, by altering personal behaviors, is admirable, says Capper. However, she emphasizes that those personal decisions must be based on logic rather than intuition.

"Consumers might think they are making the responsible, virtuous food choices, when, in truth, they are supporting production practices that consume more natural resources, cause greater pollution and create a larger carbon footprint than more efficient, technology-driven, conventional methods," she said.

See more comparisons by Capper  at a previous Cornell Nutrition Conference.

I have heard Jude Capper speak a couple of times and she makes a compelling case. Fewer, more productive animals will be less intrusive on the environment than having three times the number, as was the case back in the 1940s.  (1944 was the peak year for dairy cows in the U.S., with 25.6 million head.) But there are still critics out there. A reporter for the Yakima Herald received a letter from someone saying that more water is needed today to manage the manure at dairies than in 1950. Click here to see the discussion, including reader comments….  And, hey, Dairy Herd Management is even mentioned! The dairy industry has a good case to make, but the water issue does need to be addressed. Here is a link to our September cover story that offers insight into the water issue and may provide you with additional talking points.  - Tom Quaife, editor