Bacon-lettuce comparison questioned

Tuesday, February 9, 2016

Producing a calorie of bacon causes fewer greenhouse gas emissions than a calorie of lettuce. That's according to a new study by researchers at Carnegie Mellon University published in Environment Systems and Decisions and reported on in Climatewire. That's because, on a calorie basis, many fruits and vegetables are resource-intensive. If Americans switched their diets to fall in line with U.S. Department of Agriculture guidelines, energy use, water use and greenhouse gas emissions would increase by 38 per cent, 10 per cent and six per cent respectively.

One of the authors, Paul Fischbeck, professor of social and decision sciences and engineering and public policy, concludes that a strictly vegan diet isn't good for the environment.  However, pork isn't really off the hook. No one eats lettuce for calorie content, points out Martin Heller, a research specialist with the Center for Sustainable Systems at the University of Michigan, who published a similar study last May saying the bacon-lettuce comparison is ridiculous.

One lesson is that life-cycle assessments of foods are questionable. Maybe the newest dietary guidelines will be affected by climate change concerns anyway. BP