AskPablo: The Myth of the Beef-Powered Bicyclist

thumb_Cow.jpgIt 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?”

14 responses

  1. But how many calories does it take to get the oil out of the ground, transport it, refine it, and then transport the gas to your local filling station? Bikes come out ahead if you consider the costs of producing BOTH types of fuel, beef and gas.

  2. You make a good point but your assumptions are not quite correct. According to my data it takes 1.36 units of crude oil to make 1 unit of gasoline so, taking into account this conversion loss and energy consumption, we get 1,550 x 1.36 = 2,108, which is still less than the beef-powered cyclist (albeit a bit closer, narrowing the gap to 132). Can anyone else think of anything missing on either side of the analysis?

  3. These are very interesting observations. I take it as more of a statement to encourage vegetarianism rather than drive a car. I worked out once that driving my car used about 62 times as much energy as riding my bike, which is only off by a factor of 2 from your comparison.
    In terms of practicalities, I’ll point out a couple things so people don’t go storing their bikes right away!
    First of all, you’d be hard pressed to find a cyclist (an avid one) who is on the Atkins diet. While some energy may come from beef, a good fraction will come from rice, wheat or potatoes (which all do in fact require some fossil fuels, as does broccoli). These other foods likely use much less fossil fuel to generate.
    Also, most people who ride a bike on a regular basis, like as a bike commuter (this is where people can have the biggest impact in terms of fossil fuel use), will tend to ride at a comfortable pace, unlike someone on a recreational racing ride who might ride more aggressively. At a comfortable pace, I suspect they use less than 64 calories per mile. But this will vary a lot per person.
    And finally, as the Harpers article points out, you may have choices as to where your meat comes from, and how it was grown. If it is localy produced, at the very least you’re cutting down on shipping fuel consumption.
    Here’s a link to my

  4. Thank you Darren! I think everyone understands that this week’s analysis is aimed at confirming or busting of a silly myth. You would have a lot of trouble trying to find someone that gets 100% of their calories from corn-fed feed-lot cows, and even more trouble finding such a person that also rides a bike. Therefore I would not advocate driving over cycling to anyone, not even the most carniverous amongst you. But, if you must eat meat, I would advocate a balanced diet that includes local/seasonal vegetables and meat from animals that are not raised on a corn diet.

  5. I think it was John Robbins (son of the ice cream magnet, he became an advocate of vegetarian diet) who said that eating a one pound steak uses the same amount of petrochemicals as driving 25 miles.
    His point was not that we should drive more but that eating low on the food chain is underestimated as a path to oil conservation, not to mention water conservation and reduction of pollution from factory farming. Furthermore, in a hungry world, an acre can feed more people if they eat vegetable protein than if they eat animal protein.

  6. Eating meat may not be the only issue. I suspect that chickens convert feed into meat much more efficiently than cattle. A friend of mine keeps and breeds meat rabbits in his backyard. Transport cost is eliminated and the main energy input, apart from grass and kitchen scraps, is the pellets he feeds them.It is nutritious lean meat and comes with a fairly low energy cost. It’s better to be vegetarian but not all meats are the same.

  7. Though it’s somewhat peripheral, the methane produced from cow farts, petroleum processing, and fossil=fuel burning should be factored into this issue. Consider: How much methane does a bicyclist rider produce? Compare that figure (it must be close to zero) to the other sources.

  8. Hi Pablo, Nick, et al– thanks for bringing this up. I’ve become really interested in sustainability metrics lately, not because they’re accurate so much, but because at least they represent an honest attempt to figure out how ‘sustainable’ current lifestyles are. Calculating them is a lot more intellectually respectable than just standing on some principle (e.g. “food X is bad”) and trusting that it will lead to the right conclusion.
    Recently I and discovered that (according to the calculator) neither was even close to sustainability. Not sure whether to find a new calculator or give up and order a McMansion and a Hummer, but at least it got me beyond propaganda and in to the nitty gritty.

  9. The 64 kCal a mile must be gross calories unless this hypothetical person weighs about 280 pounds, the net is more like 32 kCal for 1 mile at 15mph. So the true numbers are about 1120 for cycling and 1550 for driving.
    Although, it is disturbing if you do the calculations; each man would use the equivalent of 3 gallons of gasoline by just sitting on the couch, if they ate only corn fed beef.

  10. “organic broccoli requires zero fossil fuel calories per calorie, except for a negligible amount for transportation.”
    That’s completely bogus! unless you live on a farm and you went outside to pick the broccoli yourself. and what about the energy required to keep it cool or frozen?

  11. Additionally, even if a biker did consume nothing but beef, that beef is keeping them alive. We must realize that while putting gas in your car really only serves to transport you and run other features in the car like air conditioning, etc, whatever, eating also sustains human life. That is to say, you can eat beef to get protein and energy and still bike… but you cannot drive your car and still get the protein and energy you need as a baseline to stay alive. So biking is indeed more efficient: you’re using energy you already would be using in the first place.

  12. It looks like Harper’s misquoted their source, so I’m afraid I think you were using a bad number for your calculations. Their figure of 35 kcal of fossil energy to make “a kcal of beef” was almost certainly from Dr. Pimental’s 1996 “Food, Energy, and Society”, which actually says that it takes 35 kcal of fossil energy to make a kcal of beef _protein_. A kcal of beef protein means one gram of beef, which is 2.5 kcal total, since the gram of beef also has 1.5 kcal of fat.

    It’s easy to see how Harper’s could have missed that subtlety, especially since talking about energy required to make *protein* is awkward and unexpected. Who knows why food and science writers usually talk about energy to make protein rather than energy to make *food*? They might as well talk about the energy required to make X milligrams of vitamin B6, or the energy required to make X grams of carbohydrate.

    Next, I’m not sure where you’re getting that 15mph biking requires 64 calories per mile, or 960 calories/hr. 704 calories/hr. seems more like it, according to (and my own experience)

    • So a cyclist going 1 mile @ 15mph needs 704/15 = 47 calories.
    • At 35 kcal of fossil energy per 2.5 kcal of beef, the fossil energy for 1 kcal of beef is 35/2.5 = 14.
    • So 14 kcal of fossil energy x 47 calories = 658 kcal.
    • At 31000 kcal/gallon, that’s 658/31,000 = 0.021 gallons
    • A 22 mpg car traveling one mile uses 1/22 = 0.045 gallons.

    So even if the cyclist eats nothing but beef, cycling still uses less fuel than driving.

    Note that the 35 kcal figure is old; Dr. Pimental says that 40 is more accurate. However, that figure is for production only, and doesn’t include processing, packaging, refrigeration, and distribution. Unfortunately I couldn’t track those numbers down to make the best comparison. If we had those figures, then cycling would look worse. Worse than driving? Hard to say.

    Now, *walking* would likely be worse than driving, since walking is around twice as efficient as cycling.

    I’m always amazed that the first thing people say in response to this (like the very first comment on this post) is, “But how much energy does it take to get the oil out of the ground, transport it, refine it, etc…” As though that amount is somehow different when the resulting product is put into a car instead of a tractor.

    Years ago I wrote what is probably the original web article on this topic, here:

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