Comments on: AskPablo: The Myth of the Beef-Powered Bicyclist

By: Michael Bluejay

Michael Bluejay — Tue, 17 Feb 2009 01:24:22 +0000

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 http://www.nutristrategy.com/activitylist.htm (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: http://BicycleUniverse.info/transpo/beef.html

By: Anonymous

Anonymous — Sat, 05 Apr 2008 23:47:26 +0000

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.

By: Carolyn

Carolyn — Sat, 10 Mar 2007 13:25:50 +0000

“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?

By: shawn

shawn — Tue, 19 Dec 2006 00:18:25 +0000

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.

By: bottleman

bottleman — Sat, 23 Sep 2006 15:20:57 +0000

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 played with an ecological footprint calculator to compare two “progressive” lifestyles 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.

By: Geoff

Geoff — Fri, 22 Sep 2006 02:53:45 +0000

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.

By: Chris Newland

Chris Newland — Wed, 20 Sep 2006 21:34:28 +0000

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.

By: John Markos O'Neill

John Markos O'Neill — Wed, 20 Sep 2006 21:19:25 +0000

To get an accurate result, you also need to add the number of calories the driver’s body burns. That is, a driver burns calories too — just not as many — as a cyclist.

What does the driver eat? To be fair, I think the driver must also eat beef.

By: Lauren Ayers

Lauren Ayers — Tue, 19 Sep 2006 01:37:46 +0000

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.

By: Nick Aster

Nick Aster — Mon, 18 Sep 2006 13:57:26 +0000

What do the folks at Niman Ranch have to say?

By: Pablo

Pablo — Mon, 18 Sep 2006 13:34:03 +0000

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.

By: Darren J

Darren J — Mon, 18 Sep 2006 13:26:11 +0000

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 not so scientific comparison.

By: Pablo

Pablo — Mon, 18 Sep 2006 11:12:08 +0000

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?

By: Andy

Andy — Mon, 18 Sep 2006 08:09:29 +0000

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.