American Dietary Recommendations May Actually Increase Greenhouse Gas Emissions

It turns out that dietary recommendations may not be a good thing for the environment. Scientists have found that if Americans altered their menus to conform to federal dietary recommendations, emissions of heat-trapping greenhouse gases tied to agricultural production could increase significantly.

In order to better understand the impact of agriculture on greenhouse gases, the scientists examined the gas emissions associated with the production of about 100 foods, as well as the potential effects of shifting Americans to a diet recommended by the U.S. Department of Agriculture-one that recommends that Americans eat more fruits, vegetables, whole grains, fat-free and low-fat dairy products and seafood.

So what did they find? It turns out that if American's adopted USDA guidelines while keeping caloric intake constant, diet-related greenhouse gas emissions would increase by 12 percent. They also found that if American reduced their caloric intake to the recommended level of about 2,000 calories per day while shifting to a healthier diet, greenhouse gas emissions would decrease by only about 1 percent.

"The take-home message is that health and environmental agendas are not aligned in the current dietary recommendations," said Martin Heller, one of the researchers, in a news release.

What's interesting is that while a drop in meat consumption would help cut diet-related greenhouse gas emissions, an increased use of dairy products-and to a lesser extent seafood, fruits and vegetables-would have the opposite effect. This is partly because cows don't efficient convert plant-based feed into muscle or milk and must eat a lot of feed. This involves the use of fertilizers and other substances manufactured through energy-intensive processes. In addition, cows "burp" a lot of methane, which is a potent greenhouse gas.

The findings reveal a bit more about how health plays a role in greenhouse gas emissions. It also reveals that reduced consumption of animal products could help reduce emissions in the long run.

The findings are published in the Journal of Industrial Ecology.