Dietary recommendations linked to higher greenhouse gas emissions

Here’s a reason not to feel bad if you don’t get your two and five a day: a new study from the University of Michigan shows that diets that conform to federal dietary recommendations could have higher carbon footprints than non-conforming diets.

If all Americans changed their diets to meet dietary guidelines, greenhouse gas emissions from agricultural production could increase significantly, researchers Martin Heller and Gregory Keoleian found.

The researchers examined the greenhouse gas emissions associated with the production of 100 foods, as well as the potential effects of shifting Americans to a diet recommended by the US Department of Agriculture (USDA).

They found that if Americans adopted the USDA’s 2010 dietary guidelines while keeping caloric intake constant, diet-related greenhouse gas emissions would increase by 12%.

However, if Americans reduced their daily caloric intake to the recommended 2000 calories while shifting to a healthier diet, greenhouse gas emissions would actually decrease by 1%.

“The take-home message is that health and environmental agendas are not aligned in the current dietary recommendations,” Heller said.

The researchers found that switching to diets that don’t contain animal products would result in the biggest reductions in diet-related greenhouse gas emissions. However, Heller says he doesn’t think all Americans need to be vegan and that animals need to be part of a sustainable agricultural system. He does think that reduced consumption would have both health and environmental benefits.

A paper by Heller and Keoleian, titled ‘Greenhouse gas emission estimates of US dietary choices and food loss’, has been published online in the Journal of Industrial Ecology. The paper is available as a free download here.