thumb_CowIt is once again time to explore the wonderful world of sustainability metrics. This week I am going to tackle the myth of the meat-powered cyclist. Here’s the story: A friend of mine once told me that it is more efficient to drive a car over a certain distance than to ride a bike over that same distance if your calories come from beef. Before passing on this great anecdote on the inefficiency of beef production I thought I would run the numbers myself. Join me this week in another exciting installment of Ask Pablo.
First we need to examine just how inefficient the conversion from fossil-fuel > fertilizer > grain > cow is. According to an article in Harpers, “It takes thirty-five calories of fossil fuel to make a calorie of beef.” While it is certainly tastier than eating spoonfuls of fossil fuels, this is pretty inefficient. By comparison, organic broccoli requires zero fossil fuel calories per calorie, except for a negligible amount for transportation.

Before talking any more about calories I need to take a moment to clarify. The “calorie” that we are all familiar with is actually a kilocalorie (kCal), the amount of energy required to heat a kilogram of water (1 liter) by 1 degree C. Technically a true calorie is the amount of heat energy required to heat 1 gram of water by 1 degree C. So what we know as a food calorie is actually 1000 calories. I will continue to use the common food calorie so that I don’t confuse things too much.

So, back to the bicycle myth… Riding a bicycle at 15 mph requires about 64 food calories per mile. Therefore you can travel one mile on 2240 fossil fuel calories (35 x 64). According to How Stuff Works, one gallon of gasoline “contains about 31,000 calories. You could drive a car 22 miles (35 km) on the calories in 217 Big Macs.” If the average car gets 20 miles per gallon you can travel 20 miles on 31,000 calories, or 1,550 calories per mile. So, believe it or not, it is more efficient to drive than it is to ride a bike (by 690 calories), if your calories come solely from corn-fed beef. If you prefer grass-fed beef, on the other hand, saddle up and take a ride!

I apologize to all of you who were hoping to see an analysis of “paper vs. plastic.” As I began my research I found numerous articles that had already been written, including a good one at TreeHugger. I wouldn’t be the first to address the question but for some reason people still don’t know the answer. So please point your browser to Google and look for “paper or plastic?”

Pablo Päster is a weekly columnist for TreeHugger.com, an experienced greenhouse gas engineer and the Senior Environmental Program Manager at Hara Software. Send your questions by submitting this form and connect to his RSS feed.