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Holy cow: Walking consumes more gasoline than driving!

Note to new readers: This article explores the consequences of using so much fuel to produce our food. If you come out of it thinking it's telling you to drive rather than get some exercise, you didn't read it! But if you like surprising numbers like this, check out the rest of my Going Green section and other sections.

In my growing research on transportation energy economics, I've come upon some rather astonishing research. I always enjoy debates on total cost analysis -- trying to figure out the true energy cost of things, by adding in the energy spent elsewhere to make things happen. (For example, the energy to smelt the metals in your car adds quite a bit to its energy cost.)

Humans are modestly efficient. Walking, an average person burns about 100 Calories per mile at 3mph, or 300 per hour, while sitting for the same hour burns around 80 Calories just keeping you warm. In other words, the walking 3 miles uses about 220 extra Calories. Calories are kilocalories, and one Calorie/kcal is about 4 BTUs, 4200 joules or 1.63 watt-hours.

While walking 1 mile burns an extra 74 Calories, on a bicycle we're much better. Biking one mile at 10mph takes about 38 extra calories over sitting. Again, this is the extra calories.

A gallon of gas has about 31,500 Calories in it, so you might imagine that you get 815 "mpg" biking and 400 "mpg" walking. Pretty good. (Unless you compare it to an electric scooter, which turns out to get the equivalent of 1200 mpg from pure electricity if you allow the same perfect conversion.)

But there's a problem. We eat, on average about 2700 Calories/day in the USA, almost all of it produced by agribusiness. Which runs on fossil fuels. Fossil fuels provide the fertilizer. They run the machines. The process and transport and refrigerate the food. In many cases our food -- cows -- eats even more food produced with very high energy costs.

I've been digging around estimates, and have found that U.S. agriculture uses about 400 gasoline-gallon equivalents per American. Or 1.1 gallons per day, or about 10 Calories (40 BTU) from oil/gas for every Calorie of food. For beef, it's far worse, as close to 40 Calories of oil/gas (160 BTU) are used to produce one Calorie of beefy goodness.

You can see where this is going. I'm not the first to figure it out, but it's worth repeating. Your 3 mile walk burned 220 extra Calories over sitting, but drove the use of 2,200 Calories of fossil fuel. That's 1/14th of a gallon of gasoline (9oz.) So you're getting about 42 miles per gas-gallon of fossil fuel.

If you eat a lot of beef or other livestock, and want to consider your incremental food as having come from beef, it's around 10 miles per gallon. A Hummer does better!

So yes, if you drive your Prius instead of walking it's going to burn less fossil fuel. If 2 people drive in a more ordinary car it's going to burn less fossil fuel than both of them walking.

Biking's better. The average-diet cyclist is getting 85 miles per gallon of fossil fuel. Still better for 2 to share a Prius. The beefeater is, as before only 1/4 as good. At 21mpg he's better than a Hummer, but not that much better.

This is a fuel to fuel comparison. The fuel burned in the cars is the same sort of fuel burned in the tractors. It has extra energy costs in its extraction and transport, but this applies equally to both cases. And yes, of course, the exercise has other benefits than getting from A to B. And we have not considered a number of the other external costs of the vehicle travel -- but they still don't make this revelation less remarkable. (And neither does this result suggest one should not still walk or bike, rather it suggests we should make our food more efficiently.)

And no, picking transit isn't going to help. Transit systems, on average, are only mildly greener than cars. City buses, in fact, use the same energy per passenger mile as typical cars. Light rail is sometimes 2 and rarely even 3 times better than cars, but in some cities like San Jose, it uses almost twice as much energy per actual passenger than passenger cars do. Taking existing transit vehicles that are already running is green, of course, but building inefficient lines isn't.

Many people take this idea as a condemnation of cycling or exercise. It isn't. Cycling is my favourite exercise. It is a condemnation of how much fossil fuel is used in agriculture. And, to a much lesser extent, a wakeup call to people who eat the average diet that they can't claim their human-powered travel as good for the planet -- just good for them. What would be good for the planet would be to eat a non-agribusiness diet and also walk or bike. How your food is farmed is more important though, than where it comes from. It's the farming, not the shipping, that's the big energy eater.

Obviously if you were going to need the exercise anyway, doing it while getting from A to B is not going to burn extra oil. Human powered travel well above the need to exercise is the only thing that would hurt, if fueled by U.S. agriculture. And eating a high calorie diet and not exercising would be just as bad.

Happy eating!

What's not wrong with these numbers

As I note, since most of us need to exercise anyway, this is not at all a condemnation of walking and cycling, but rather of the amount of fossil fuel that agriculture uses. However, a lot of people still find faults with this analysis that I don't think are there.

  • No, it doesn't matter that making the fuel costs energy. It's (roughly) the same fuel going into the tractors as going into the gas tanks. We're comparing fuel in tank to fuel in tank. But if you really want to factor that in, about 82% of well energy makes it to the gas tank of the car or tractor.
  • Yes, I do account for the fact that just eating or sitting consumes calories. This calculation is based on the extra calories that biking or walking take, compared to sitting in a car. The base "keep you alive" calories are not counted, but they do require more fossil fuel to create.
  • I don't include the energy required to make a car, which ranges from 25% (Prius) to 7% (Hummer) of its lifetime energy usage. However, most cyclists and pedestrians still own cars, so this is still spent if it sits in the garage while you walk. And while a 2000lb car may take 60-100 times as much energy to make as a 30lb bike, this is not so large a difference if expressed per lifetime vehicle-mile.
  • This is based on the USA averages. Of course different food means different results, but doesn't change this story, which is about the average eater.
  • I don't include the energy needed to build roads for bikes, cars and food delivery trucks. The reality is, we're not going to build fewer roads because people take some trips walking for exercise. Nor are people going to not buy a car because they do that.


I'll probably end up in the spam-blocker for posting several links, but the driving vs. walking comparison has been made and criticized before. See:


with some of the key points being that people who drive, drive farther than people who walk, walk, and that if one considers all carbon wasted in our inefficient food supply system, it's certainly discouraging, but if one compares it to the carbon cost of creating and maintaining a car, the latter ends up the larger environmental loser.

The point is not to tell people to drive rather than walk. It's a point about the food system and the oil it consumes. That people who drive go farther isn't relevant to this analysis, because this is a per mile analysis to make a point, not an argument against walking. (Though in fact, I've often made the walk/bike vs. drive choice, especially when I worked 2 miles away and would bike commute half the time and drive half the time, depending on schedules and weather. But I made the choice for fitness reasons, not simply to be green.)

The point is how surprisingly inefficient we are as a system, using 400 gallons of fossil fuel every year to feed ourselves. (Because I don't commute, I probably burn about that every year to drive myself, but much more to fly.) What's amazing is that the comparison is even possible, not the fine points of it.

First, I'm not going to criticize your numbers. I agree whole-heartedly.

Just a comment about the fitness reasons you mention. I sometimes think of transportation by bicycle as "free" in terms of energy, yes free, as if I were driving I would go for a one hour workout after I come home. I'm able to deduct the commuting time from my workout, and still get the same result.

In fact, I once prepared for a marathon this way. The whole season I was cycling everywhere, and did an occasional run, perhaps 5 km every weeks, just to keep my legs used to the asphalt. It worked very well! :-)

I may be missing something (math makes me nervous and I might have blacked out during the presentation), but who said that bikers eat more than drivers? Assuming american bikers and american drivers eat the same 2700 cal pile o food, how is it you only add it to the biker's spreadsheet?

As noted, when I did the calculation, I worked out the extra calories consumed walking or biking compared to sitting down. So of course drivers eat. This analysis applies only if the walk/bike for transport was special exercise. For example, if you exercise every day, some days on a stationary bike and some days to get somewhere, you aren't changing your energy budget. If you decide to walk somewhere and otherwise you would not have done that exercise, then it takes extra energy.

However, again, this misses the point, which is not that we should sit down all day and not walk places. The point is we have created a system of agriculture where feeding ourselves consumes large amounts of oil, no matter what we do with the energy.

Wow -- I am indeed amazed that I cause the burning of 400 gallons of gas (or equivalent) by eating for a year.

But on the other hand, if the farmers were not using their spiffy air conditioned diesel tractors and combines, then we would need many sweating men following after teams of horses pulling a plow; also many laborers with scythes and rakes, to bring in the harvest. How then do we calculate the energy consumption of those? Also, how do we value the hard use of humans and animals?

I think the answer does not lie in using LESS energy -- but MORE. But the energy source must be non-polluting in whatever form. Nuclear qualifies; solar; hydro, in the few places possible. We need methods to store energy for peak and overnight use. If we had super-abundant very low-cost energy, then we could produce hydrogen for our cars, clean water from sea water, could use incandescent lamps (if it pleases us) and set out thermostats as high or low as we want.

I have to tell you I lose significantly more weight driving a race car, OTR truck, farm tractor or heavy machinery (I own a track loader), than I can walking the same number of hours!

A person who is commuting in heavy traffic, even if they are driving a small car is not only sitting, they are first of all THINKING and that consumes the greatest part of the calories in the human system when at physical rest, which, when one is driving, is heightened significantly as one is not only thinking, they are also sending impulses to their various muscles and the muscles are also engaged in controlling the machine, so, even though an idealized Prius MIGHT get the blood barely pumping if one is merely driving along an open freeway with the cruise control on, if you are operating any kind of machinery where thinking, looking, changing gears often or having to keep track of a lot of crucial details such as fuel consumption [ironic that this is part of the equation in that it consumes fuel to monitor fuel consumption] oil pressure, air pressure [air brakes], tire pressure [one has to actually get out and walk around to perform this act as well as apply thought to it, except on some of the newer, more sophisticated, self regulating trucks of which there are still very few on the road] and keep a log book, look for cars trying to sneak by and get themselves killed, tailgaters who try to save a few miles per gallon while getting smashed when you have to stop suddenly, load balance and shifting, etc, etc, etc.

Taxi drivers and city bus drivers have it as tough or tougher even!

Never assume that a person seated in a rolling death trap is not spending a lot of extra energy just keeping alive long enough to get the the destination too!

they are not saying that they dont eat
they are only mentioning the bikers because that is the main object of discussion
they are talking about walking and biking being better for the environment and saying that it burns alot of calories

Even in Oz it's not good, although we haven't yet achieved the true hideousness of the US food chain. So our food costs are lower but still obscene (total cost, not dollar cost).

The one thing you slid past was the vegetarian option - if a higher meat component pushes the cost up, lowering it pushes the cost down. For the most part, anyway - me eating roadkill when I'm cycle touring is probably fairly neutral, in that few people farm animals specifically to make them into roadkill, but a lot of native animals become roadkill.

Also, talk to us about packaging, Brad, that's another exciting area of "just how dumb are we, really?"

And finally, have you looked at scanning/OCR recently? I've bought a Sony PRS-505 (my first ever Sony {hoik spit} product), and I'm struggling to find some books online, so I'm using my 30D and a sheet of glass to scan books and OCR them. Slow, but beats paying another $2000 for a decent sheet-feed scanner and cutting the spines off my books. There's got to be a better way...

Off topic, and I haven't yet tried it, but omnipage 16 says it will handle photos including the curvature that comes near the spine. I am cutting spines for my sheetfed, though, but only on books like old computer manuals.

Vegetarian option is of course better. Eat food from your own garden would be tops.

"We eat, on average about 2700 Calories/day in the USA"


Actually, I thought that was kinda low.

I'm consuming an average of less than 1000 calories per day (I'm supposed to be wating 1250, but I'm being hardcore and don't give me crap about it), in an attempt to lose weight.

The idea of weight loss is not to consume more calories to make up for the exercise, but to add the exercise to increase the caloric deficit.

Therefore I'm *not* eating more, and I'm walking more and driving less so that my iPhone makes my numbers really low, and in a day or two my scale agrees.

In this case, it would seem that exercise *is* green, since I'm doing the exercise *and* eating less than normal anyway.

Therefore, everyone should diet and get thin.

There's just one thing more to factor into the possible side effects of this. If everyone lost weight and started looing really good, how much energy is comsumed by the manufacturing of the higher quantities of condoms that would then become necessary?

Just giving you kudos for the "condoms" comment when everyone starts looking hot!!!! Point taken and thank you for the laugh.

A similar argument, on a slightly different topic, is made about ebikes by Justin Lemire-Elmore on ebikes dot ca.

Brad, you make a good point about agriculture's high consumption of fossil fuels, but it is absurd and misleading to say that walking or riding a bicycle consumes significant amounts of fossil fuel (e.g., two people riding bicycles consume more fossil fuel than two people in a Prius). Perhaps your calculations on walking and cycling are intended tongue-in-cheek. In one of your responses you acknowledge that if you exercise anyway, on a stationary bike, you use the same amount of food energy (it's worse if you drive to the fitness center or if you run on an electric-powered treadmill). So for the person who would do some other exercise if not bicycling for transportation, the bicycle trips are really free: zero gallons per mile (miles per gallon approaching infinity).

For the person who would not exercise much if not bicycling for transportation, the trips are also essentially free. You dismiss dave's comment too easily. You seem to believe that the exercising person really does consume more food, and therefore fossil fuel, than the non-exercising person. You have neglected the fact that there is a lot of waste at our end of the food production-preparation-consumption-utilization chain: We eat more food than we use and we buy more food than we eat. (The unused energy from the food we eat either gets converted into fat stores or goes literally down the toilet.) You have to show that the person who exercises actually buys more food than the person who does not, which I doubt very much is the case. And even if we allow, for the sake of argument, that the person who travels an hour per day by bicycle actually does eat a little bit more, the extra food could be completely carbs (pasta, pancakes,...). That would change your calculations, which assume the extra food is in proportional amounts of the average American diet, which includes a lot of meat.

If you want to do something useful with calculations, why not show us how many gallons of gasoline we could save per year by making various kinds of choices: vegetarian diets vs. eating meat (various animals), buying food grown close to home vs. food that is imported (can we save gasoline by importing certain foods from places where less fossil fuel is used in agriculture?), living close to where we work vs. living far away, and of course various means of transportation vs. driving alone in a car? For starters, I estimate that I saved about 100 gallons of gas per year when I bicycled to my job, which was five miles from home (compared to driving my car, which gets about 25 mpg in the city).

Yes, that's a valid point, it does depend on the food you buy rather than what you eat. But I would strongly suspect that people who eat more calories per day do buy more calories per day, even if they throw away some good portion of them. I would be surprised to learn that the heavy eater is more frugal about buying closer to what they eat than the lighter one.

And yes, it's only if you truly burn more calories through the exercise, which is not the case for somebody getting their fitness exercise through walk/bike, but it would be true for a bike commuter who has a long enough commute that they clearly get more exercise than they need to maintain fitness.

And also, people who eat a lot of food just because they eat a lot of food (ie. us fatter folks) are just as guilty of consuming calories that were generated with fossil fuels.

However, the point remains a good illustration. If you take serious exercise, like biking a century for tourism, it is fair to argue that doing so is no greener, fossil-fuel wise, than riding an efficient vehicle the same distance, if fueled by typical U.S. agriculture.

Uh, yes, since you must burn calories to walk or ride a bike, then you will ultimately need to take in more calories than you would otherwise. Your protein intake must go up in proportion to the added calories too, if you are to remain healthy.

It's easy to criticize modern agriculture, but I doubt we could feed everyone enough calories to stay alive without it, much less provide enough calories for everyone to use bicycles as a practical form of transport.

I think people are missing your point because you buried it. If you want to make a point about embodied energy of agribusiness food, make it; don't talk about biking or walking versus driving.

I did a similar analysis and got:
Riding 6 MPH on a local organic diet gets around 2500 Miles per Gallon (of fossil fuel).
Riding 14 MPH on that diet gives around 679 Miles per Gallon.
Riding 6 MPH on an American diet gives around 250 Miles per Gallon.
Finally, riding 14 MPH on that diet gives around 67 Miles per Gallon (not much better than a prius).

I also hereby claim that an American who bikes (say 5 miles) to work every day is eating less than one who drives that same five miles. All else being equal.

Thank you kindly.

But they could well be true. Though at this level we can start looking at the human engine as a consumer of renewable fuel, which is what the food farmed without oil is. Figures in that area suggest about 600 to 900 miles per gallon (of vegetable oil in gasoline equivalent) as a floor.

Very good point. (Note also that according to posting by borderline on Brad's figure of 38 cal per mile for biking at 10 mph may be wrong: borderline quotes 38 for 20 mph and only 26 cal per mile for 10 mph.) Getting around on a bike at about 6 mph is what many Indians and Chinese have been doing for about 100 years or so, while eating high-carb diets from food grown locally without much use of petroleum. Now millions of them are getting off their bikes and into cars, contributing substantially to the increased global demand for oil.

I do agree as you look around the web I do see a lot of different charts on the caloric requirements of biking at various speeds for the typical man. (Women need less.)

I see values ranging around 7 kcal per minute for 10mph biking, with, as you suggest, a pretty good drop into the casual biking speeds below 10mph. Compared to about 1.2 per minute for sitting.

At 6 minutes per mile (10mph) this provided the number I see above, but for more casual biking, 23 kcal/mile extra may well be valid.

Note that this is about the U.S. diet, not other foreign diets. 5% of the world's natural gas goes into fertilizer, but a lot of that is in the developed world.

You've made some very interesting points. The human cal/mi is the most suprising, so of course it has drawn flack. It certainly suprised me. But as you point we eat food made by modern ag, so we're actually using far more btus of energy input than we see on our plate. I'd be curious how much a calorie of healthy food - fruits, vegtables, nuts NOT bread or pasta costs to produce.

Assuming one has a shower available at commute's end, 15 mph for an unambitious cyclist and 20mph for one using the time for training is more realistic. That is speed while underway, not counting stops for intersections etc. A lazy commuter cyclist putting along at 10mph needs to have their 2 wheel licences revoked! (joke).

Bike cal/mi is not a single, fixed number. Much depends on whether the researchers have a clue about cycling. A traditional road bike with drop bars and 100psi tires which a serious commuter uses rolls far more easily than a fat tire mountain bike or an old 3-speed, both with extra drag from riding upright.

As for calories, while I like to think that I'm greener than all while on my bike it's unavoidable to eat more at some point. Sure, one can can go thousands of miles on the 10-25# of excess fat many people lug around, but once that's gone you have to replace the calories you burn off or you'd consume your internal organs and die. Worse than that, excercise raises your base metabolism, so you'll eat even more than the cycling calorie calc suggests.

But even if driving saved fuel over excercise, I would not suggest sacrificing your health to save fuel. If you're *honestly* that concerned about the enviroment, convert yourself and any offspring you have so far into soylent green and save untold harm to the environment. Sounds snarky, but no matter how much one "conserves" it is totally undone by having kids, sending them off to a college campus (which uses more energy to maintain the grounds for a month than the most wasteful family uses all year), having them see the world (unneccesary travel), have more kids and so forth.

where did you get that information from??
i have been trying to find it for ages and i have had no luck
i am doing about walking and biking and the gallons in school and i have had no luck finding anything that i can put in my table
please reply and tell me the address please

I'd be curious to see where an electric bicycle would fit in here. A typical electric bicycle will weigh about 50 lbs and provide 360 Wh of energy to help propel a bicyclist. I would expect much better results per mile than a regular cyclist since you're replacing that much energy that a human would've generated with 3 cents worth of electricity. But it may be pretty close compared to an electric scooter. An electric bicycle would only travel at regular bicycle speeds and would not have to overcome all the higher wind drag an electric scooter would experience. It would be lighter as well.

I guess I'd be curious to see numbers where the bicyclist is not pedalling vs moderate pedalling (providing half of the total energy).

on general transportation efficiency. Electric bikes are very good, even better than a human from pure food (forgetting the oil) at the base, but the fact that electricity generation and transmission is only 33% efficient huts a little, but they are still the best even then.

I understand your point, and yes, petroluem driven agriculture is incredibly inefficient, and there's far too much beef in American diets. Those points stand.

However, there is one part of this comparison that's not fair, and has been brought up in other criticisms of this argument. If you're going to calculate in the energy required to raise the "fuel" for the human body, you have to do the same for the gasoline. My guess is that your point would still stand, but that's a fair criticism. You can't just pretend that the gasoline came from nowhere.

While I do know the energy costs of drilling, extraction, refining and shipment -- get get 82 barrels of oil out for 100 in the ground -- this number is quite deliberately not in the calculations.

That's because the fossil fuel spent in agriculture is no different from the fuel put in cars. Why would I calculate the energy cost of the gasoline in the car but not do it for the diesel in the tractor? It is easiest to look at fuel to fuel.

Now most of the fuel used in agriculture turns out to be natural gas. 5% of the world's natural gas is used to produce ammonia for fertilizer. In this case, it must also be extracted and moved by pipeline. Just as it is if it's burned in a power plant to run an electric train. I believe the figures I found for fossil fuel use by agriculture are post-delivery fuel, just like cars.

Even if I were to unfairly bias things by adding the extract/deliver cost to the fuel for cars, and not for tractors/fertilizer, it would not change things by more than 20%.

That’s because the fossil fuel spent in agriculture is no different from the fuel put in cars. Why would I calculate the energy cost of the gasoline in the car but not do it for the diesel in the tractor?

That's not what you're doing. You're trying to calculate the cost in fossil fuels of fueling a cyclist. And to get that cost, you're calculating what it costs to grow the cow and bring it to market. If you're going to use the energy it take to get fuel into a cyclist, then you have to calculate the energy it takes to get fuel into a car. It's a fair comparison.

Because what you say makes zero sense to me.

1 gallon fuel in well -> .82 gallons gasoline in car tank -> 41 miles driving in Prius

1 gallons fuel in well -> .82 gallons fuel used in agriculture -> 2,580 Calories food -> 35 miles walking or 68 miles cycling at 10mph.

1 gallons fuel in well -> .82 gallons fuel used in agriculture -> 650 Calories beef -> 8.7 miles walking or 17 miles cycling at 10mph.

As you can see, the reduction of well fuel by .82 to tank fuel does not alter this equation. It doesn't even matter what the factor is, whether it's 82% or 5%, it would result in the same ratio. It takes energy to get fuel to the farm, and similar energy to get fuel to the car.

thanks very much for that information
i have been trying to find that for ages and i have had no luck
thanks again

My observation is that the average American cyclist is thinner than the average American. It may be that the transportaton is fossil fuel free or even better than that.

Have you consider how many calories are burnt by a human while driving the car? That is surely more than what is burnt by just sitting around?
So while calculating the mpg for a car, you should also count the extra calories burnt by the driver!

I don't have a source for what extra calories driving takes over sitting, but I can't imagine that it's a great deal more, nothing compared to walking or biking.

He might be on to something, though; While not physically strenuous, city driving can be rather stressful and agitating, which I imagine would raise the baseline burn rate.

Also, do you know if anybody has examined whether or not road maintenance, i.e. asphalt replacement frequency relative to vehicle weight, comes out to anything more than a rounding error?

According to DietPower (the nutrition and exercise software I use):

For 20 minutes of driving the following vehicles, the average human burns the following amount of calories above those that would have been burned in watching television for 20 minutes:

car 16
police car 31
motor scooter or motorcycle 47
bus, heavy truck or tractor 63
heavy machinery 156

converting this to per-mile would be tricky because the above vehicles travel at different speeds. However, since 20 mph is a fine rule-of-thumb for in-town driving, those could be considered rough per-mile figures as well.

For comparison within the same software, 1 mile of each of the following activities burns the following amounts of calories above television watching (or other basal metabolic-level activities):

walking 1.5 mph (40 minute mile) 63
walking 2 mph (30 minute mile) 70
walking 2.5 mph (24 minute mile) 75
walking 3 mph (20 minute mile) 77
walking 3.5 mph (17 minute mile) 79
walking 4 mph (15 minute mile) 94
(naturally these figures go up if one is walking uphill, in snow, etc)

light (under 10 mph) 28
leisurely (10-11.9 mph) 43
average (12-13.9 mph) 51
intense (16-19 mph) 59
competitive (20 mph or faster) 70

Personal surprises: I didn't realize driving heavy machinery was such a workout.

I was stunned at first that a mile of furious pedalling burns the same calories as a mile of slowly strolling but then I thought about the fact that a mile at 20 mph on a bicycle is 3 minutes while a mile at 2 mph on foot takes ten times longer thus furiously pedalling is a more efficient exercise as it burns calories ten times as fast. (But if, like me, one only gets exercise when one needs to go someplace, walking might be more exercise-efficient while more time-consuming.)

Sorry, I just woke up. At 20 mph, those 20 minute vehicle figures are for 6.67 miles.

One miles would be:

car 2.39
police car 4.65
motor scooter or motorcycle 7.05
bus, heavy truck or tractor 9.45
heavy machinery 23.4

I guess driving heavy machinery isn't quite the workout it first appeared to be.

For all the cheerleaders who insist that the numbers must be wrong because bycyclists eat less than the "average" American, or they would be exercising anyway (thus making the exercise of bicycling irrelevant to the overall petroleum footprint), you seem to be missing a HUGE point.

Unless and until the average Joe Sixpack begins bycycling on a regular basis to REPLACE his current driving habits, the overall impact on national fuel consumption is minimal.

Once Joe Sixpack IS cycling instead of driving short distances, that doesn;t IN AND OF ITSELF, change any of his OTHER habits -- thus the extra metabolic energy consumed in cycling versus just sitting in a car driving the same trip IS an additional energy consumption. So, comparing the total petroleum cost of the food to produce that extra energy (including teh cost to get it from the market through the kitchen and down his gullet) is going to count. When Joe SIxpack feels hungry after biking 10 miles instead of driving, he's going to get a sugar and cream laden coffee to wash down his sticky buns and sausage McMuffin.

The asusmption that Joe Sixpack will magically transform his lifestyle into one that is typical for bycycling commuters is insanely naive. He is still going to be the same beer-swilling, pizza devouring, hamburger grilling (on a propane grill or worse yet and electric stove, no doubt) pig he is ALREADY. And he's going to offset his additional metabolic exercise with teh same type of high-petroleum impact crap he already eats when he gets bored.

People who bycycle commute are ALREADY predisposed and more likely to have lower total footprints in other ways -- they tend to eat healthier, wastefully consume less, and would be burning off those calories ANYWAY. But the bicycle doesn't magically transform them -- you've confused correlation with causation. They bicycle (in large part), becuase they are the type of people to do such inherently greener activities. . . bicycling doesn't make them so.

If you were made Emperor of America, and you waved your wand and made all cars simply not work for short range commuting, that effect will not turn Joe Sixpack into a lean, mean, recycling machine, just because he huffs and puffs his way to work on a bike each day.

This is quite interesting. We are certainly going to have to learn to be thorough in energy accounting if we are to understand our fuel and climate problems.

I have another point to add: In cool climates (like the netherlands, germany, scandinavia where biking is popular), or in winter, the person driving the car will travel in an environment close to his/her body temperature (car heating). This heat is waste heat from the engine and costs nothing 'extra'. However, as our bodies seek to maintain the same core temperature in any ambient temperature, we will lose more energy when the difference between outside and body temperature is greater, as when riding a bike. Research seems to support this idea:

So spending an hour or two riding a bike in cold or rainy weather could significantly increase energy needs. This, and the idea that the cyclist will eat more, is supported by everyday experience: a desk-worker who spends a day out in the cold or doing hard physical work will often notice that s/he is much more hungry at the end of the day than usual.

I have also wondered if higher indoor temperatures contribute to obesity - I have noticed that in some countries where consistently lower indoor winter temperatures are tolerated, people are thinner, sometimes despite a heavy diet. This (small?) difference could tip the equilibrium of energy consumption over several months or years.

but how much energy does it take to refine and transport the fossil fuels everyjthing seems to use and abuse?

But because it comes up so often, I will repeat what I said above. It doesn't matter. It's (almost) the same if it takes 99% of the energy to get oil out of the ground as if it takes 1%. Because we are comparing oil and gas used by agriculture after it was taken out of the ground and refined with oil and gas used by cars after it was taken out of the ground and refined.

So those figures don't alter the equation. Now I will answer that estimates suggest about 82% of the energy in the ground makes it to the tanks of the cars and the tractors. But the 82% is on both sides of this comparison -- almost. I say almost because a lot of agricultural use is natural gas for fertilizer. Natural gas needs little refinement, though it comes as a result of the same oil drilling work, generally. I don't have its figure, but if you want to assume zero, then at most it does 18% better than oil in this component of the equations.

I'm just curious as to where you sourced the information about how much fossil fuels are spent in the production and shipping of agricultural produce. I'm not questioning your conclusion. I'd just like to see if there is also available data for Asians also, just to see how it compares - since South Asian agriculture seems to use more human labour.

I worked from an article citing this study which calculated 530l per person within the ag sector, but over triple that in total. There are other similar articles around.

OMG people! You're beating the details to death and it's nothing but mental masturbation. And you're not going to be any more satisfied by this nit-picking either.

The point that using the least energy to achieve any task is not always obvious, but not even readily determinable, is made and clearly so. Let it go. Grasp the point made, and make your choices. Don't argue the details.

Will the world's use of energy change one iota if you make via your discussion even a 40% correction to the numbers used? No. Will YOU drive to work instead of walk, or the other way 'round, depending on the numbers? I doubt it. Our average commute in this country is just too far to walk, so you won't, no matter how much less energy it uses.

Now, why don't some of you geniuses apply your turgid grey matter to convincing the world's population that they should give a crap? THAT task would be worth all the mental energy you're putting out. One of you might think eventually think of something that's, well, genius!

Brad, if you read the article you cite it is clear that the actual fossil fuel intensity of agricultural styles varies significantly from society to society. The authors of that paper make the point that North American/Australian agricultural systems produce 1 to 2 times as much energy in food as is consumed as fossil fuels in its production (ie; it is efficient) whereas in most European agricultural systems, and in Japan, the system is highly inefficient with multiples of input fuel energies over output energies of food energy - in other words, ineffienct. While African agronomy is fossil fuel efficient (30:1 food energy output vs fossil fuel inputs) this is relatively speaking not very land-efficient nor efficient for human capital. ie; one would have to argue that human labor in the food chain in low-technology countries replaces fossil fuel energies significantly.

The fact is also that, whilst beef production in America is done on cereal feeds in feedlots and is inherently inefficient, the American vegetarian is actually more fossil fuel efficient than the Chinese average person because American fertiliser is coined from natural gas and Chinese from coal. So one can argue that the most ethical and environmental choice is to become an American citizen and eat a non-organic American vegetarian diet (given that organic farms are less energy efficient than non-organic broadacre commercial farms).

Going down this route, you can reduce your fossil fuel intensity per calorie to as little as a sixth of a Japanese person, and perhaps half of a Chinese person. That tends to throw a spanner in the works. Indeed, one thing this analysis tends to conclude is that the best way for American people to reduce envirnmental impacts of fossil fuel utilisation in agriculture is to, in fact, subsidise and encourage Chinese uptake of natural gas nitrogenation as opposed to using coal. This efficiency alone would reduce carbon impact and input energy intensity dramatically.

I'm writing an article about the behind-the-scenes energy costs of cycling versus riding a moped. I know that each Calorie of food takes about 10 Calories of gasoline to produce/deliver/store, but how many Calories of gasoline does it take to produce/deliver/store a Calorie of gas? that's the final figure I need for my article-- thanks so much!

The figures I have read suggest about 82% of the "in the well" energy makes it to the tank, the rest used in refining, drilling and transport.

I don't have the figures for coal. It's worse for tar sands syncrude of course. You'll have to search for exact cites, should not be too hard.

Note however that this number plays a limited role in comparing the moped and the fuel cost of agriculture. The fuel in the tractors has the same cost of refining and transportation as the fuel in the mopeds. However, much of the fuel cost is in fertilizer which is made from natural gas, and it has a different cost of extraction (lower) than the motor fuel, and I don't know the cost of conversion to fertilizer.

Fascinating analysis. As a cyclist, every instinct in me is to take your analysis apart and I see several people have tried and mostly failed. I gave up until I thought of this. What is the fuel to wheels energy cost in a gallon of gas? Surely just as food takes a lot of energy to produce and transport, so does gasoline. Are you comparing apples to oranges when you measure the energy content of extra food calories based on the physical energy content of a gallon of gas? Don't you have to compare to the energy content of the gallon of gas plus the energy it takes to produce and deliver that gas to the consumer?

I would also add that as cyclists are slimmer on average than the general population that cyclists do not replace every extra calorie burned with one more eaten. Slimmer people burn fewer calories at rest so if cycling does in fact contribute to maintaining lower body weight then the net calorie consumed as a result of cycling could be much lower than your assumptions even negative.

And it is also not true that anybody does not replace every calorie consumed with one eaten. If you don't do this you lose weight, and eventually die. Everybody.

This compares fuel in cars to fuel in tractors and machinery, plus fuel used to make fertilizer. It's fuel to wheels for both.

Brad, I understand now your point that the comparison the gas energy content of food is valid. But you are missing my second point. People with a higher body mass index (BMI) burn more calories at rest. As one puts on weight, the amount of calories that you can consume without gaining more weight increases. If cycling causes someone to maintain a lower body weight than they would without cycling their baseline metabolism will burn fewer calories all the time. The savings in calories will offset some and possibly all of the calories burned cycling (or any other exercise).

Professional cyclists in a stage of the Tour de France will burn 4,000 to 5,000 calories pushing their daily consumption up to 7,000 calories or more. Here your mpg calculation is valid and then some (you should even add in the team cars carrying wheels and spare bikes and the helicopter flying overhead with the TV camera). But a commuter who bikes 12 miles round trip every day burns only an extra 400 calories. A man who weighs 150 lbs with a normal BMI may increase his calorie intake say from 2400 calories per day to 2800 calories per day and maintain his body weight. However if the same man were to be 30 lbs overweight (probably average these days) he would have to consume 2880 calories per day to maintain his body weight. This is how cycling to work could mean no net increase in calories and thus no fossil fuel use. And it is an accurate observation that the average cyclist weighs 30 lbs less than the average non-cyclist.

There are compelling reasons to exercise that outweigh any concern about the environmental consequences of food calories. Being sedentary contributes to many diseases and reduces your lifespan. The obesity epidemic suggests that it is not normal for sedentary individuals to consume only a maintenance level of calories.

On another note, walking and cycling (and mass transit) are better for the environment because people who walk and cycle live in denser cities an enable cities to be denser. Above all automobile use leads to more miles traveled and even if the energy use is no worse per mile the increased distances result in more GHG released.

The real point of your analysis (which really is brilliant) is that cities need to become denser. Outside the market forces that direct development, communities need to rethink policies that promote low density automobile dependence - things like parking requirements, setbacks, minimum lot sizes, street widths and the like.

However, the real point is the efficiency of agribusiness, not about the density of cities at all.

It doesn't matter that bicyclists are healthier, waste less food, and consume less than cheeseburger gulping fat slobs in Hummers.

becuase the cheeseburger swilling fat slob is STILL going to be a cheeseburger swilling fat slob if you magically made his Hummer not work and forced him to ride a bike to work. When he gets near work, and he's tired, sweaty, and hungry from low blood sugar, he's going to pedal his ass into the McDonald's parking lot and tank up -- and it won't be on home grown vegetables that used non-petroleum based fertilizer.

He's just going to end up eating more. Oh, he'll have nicely toned leg muscles under the layer of fat. But he will still be a net consumer of more petroleum than if he drove to work.

You DO NOT make people into lean, green, health machines by putting them on bikes. People who WANT to be lean, green, health machines CHOOSE to ride bikes.

The fact that one may bike to work is less relevant to their health and overall calorie consumption than the fact that they have CHOSEN to do so.

You seem to assume that we realize all the calories we get from the agribusiness, but a lot (more than 50% according to some UK sources) is wasted (so most of it ends up in landfill producing CH4, and needs more energy to be refrigerated/waste-managed).

It is my impression, but a serious study should be conducted, that walkers and cyclists tend to finish-up what's on their dishes, while drivers are more prone to "waste" it. Also, driving to large supermarkets make people overshop, for carrying is not a problem; and overshopping is one of the primary reasons behind excessive domestic waste (in the UK alone, each day 5000 chickens are thrown in the bins for being past their sell-by date).

Well, other than what you have said about some people wasting more food than others (which is difficult to quantify) the amount of food wasted does not affect the calculations about how fuel-inefficient American industrial agriculture is, which is what this article is about. It is not about bicyclists.

People who bike and walk commutes that others would noramlly drive do not eat less and waste less food BECAUSE they walk or bike.

They walk or bike BECAUSE they have a "greener" outlook -- which ALSO leads them to be less wasteful and healthier in other areas of their life.

"Green" leads to "healthy eating" and "bikes".

"Bikes" (in and of itself) does NOT lead to "healthy eating" and "green". It just leads to "more leg muscles, better wind". (Which, in the absense of "green" and "healthy eating" just leads to "shoving more processed crap down your gullet.")

A wasteful fat slob forced out of his car at gun point and on to a bike will STILL be a wasteful fat slob. He'll just be hungrer, so he'll eat more to compensate.

Mandating behavior does not equal mind control. Until you can psychically reprogram Fat Slob's mind to make him a green, healthy person, just like the people who choose to bike commuting distances, he will still be a fat slob with fat slob habits. (Of course, only now, he will hate bitterly the people who took away his comfortable car, and he will oppose their aims - no matter how good those aims might be - with ever power at his disposal.)

You cannot make people love you by forcing them to spend all their spare time with you, you cannot make people love your god and believe your religion by forcing them to convert at swordpoint and marching them under guard to church every Sunday, nor can you make someone an environmentally conscious vegan by forcing them to abandon lifestyle choices they want. It's the same fallacy in all three cases.

It's irrational to think otherwise.

You may have missed the note that this article was about the fuel inefficiency of agriculture.

So how much fuel am I using when I cycle up to 350 miles a week, on average I am doing around 200 miles a week at around 19mph average.

Probably eating around 2500 calories a day.

You're doing pretty well if you only eat 2500 calories per day. It depends what your food is and how it's grown when dealing with any personal situation. This article did the math on average US agriculture and beef.

You're biking for around 10 hours you suggest, perhaps 5 hours more than you need to maintain your fitness level. So look up Calories consumed by a person of your weight cycling at 19mph and subtract Calories used sitting down. That's how much extra food you are eating. The multiply by 10 to get fuel calories to bring you the average food. There are 31,500 Calories in a gallon of gasoline, thus 3,150 food Calories for each gallon-equivalent.

Another few points to consider about bike riding:

they have 1 extra shower a day
they wash 1 extra load in the washing machine a week.

So factor the energy used to heat the water as well as for the washing machine.

Another few points to consider about car riding:
- car drivers wash the cars once a week
- dirt from car exhausts and tires force people to use 1 extra load in the washing machine a week
- cars require wider streets which need more energy to build
- cars induce noise reduction infrastructure which needs energy to build
- cars induce a traffic police system which uses energy
- cars induce excessive oil use and thereby require the maintenance of an army with huge energy use
- car use leads to lack of exercise which must be substituted in a gym, which requires energy
- car use in cities makes people move into the suburbs, which comes with huge energy costs due to additional commuting
- car exhausts cause lung problems which cost energy in the health system
- car accidents cause energy costs in car industry and health system

I'd say I'd have to agree with this article that your calculation mostly just functions for shock value, not because it in any way takes fully accounting of the energy used in each activity. You've taken a single snapshot of driving a car today so you can then nicely skew your results by only comparing the fuel that the car consumes to the *entire* process of raising beef: including the fossil fuels to provide the fertilizer; to run the tractors, to process and transport and refrigerate the food and to grow the food that the cows eat. Then you wave your hands and explain away why you don't need to take account any process that is required to get the car there. In this way you can rig the contest so driving always wins out over walking.

The cars and the infrastructure in which to drive them don't just appear out of thin air. They require mining raw materials, factories, labour, highways and roads, road widening, parking lots, filling stations and so on. None of this is included in your calculation.

To make it easier to avoid the embedded energy of the car you restrict your calculations based on a subset of humanity: those Americans adults that already own cars. Yes, if you rig the calculations this way you can avoid the messiness of reality. And by only including a small window of time for the car traveling you can avoid the messiness of calculating the energy requirements of providing the entire asphalt/concrete/landscaping infrastructure in order that the car can actually be there.

If someone chooses to walk, bike or take transit it means one less car and means that much less requirement for wider roads, freeways and parking lots. One can easily imagine this impact when one imagines what a place like New York City would be like if *everyone* decided to get from point A to B by automobile instead of by walking, biking or transit. From an estimate I saw some place, we could imagine the entire island of Manhattan being dedicated to roads and parking with nothing left for the actual buildings let alone parks or sidewalks. Currently only about 50% of NYC adults own cars and thank god for that (China is at 13%, Brazil at 15%, India at 1%! - If they moved up to about the 95% car ownership rate of adult Americans you'd have to include the estimated energy costs of doubling (more or less) the entire NYC network of roads and parking lots. That's a huge amount of energy. Now imagine if the rest of the world moved up to America's car ownership level so they can have the option of taking the car to the corner store. Wow. Massive.

Unless you adjust your calculations to the *full picture*, you are hardly participating in "transportation energy economics" or "full cost analysis", but merely an exercise in convenient rhetoric.

As I have said, this article is about the inefficiency of agribusiness and not really about cycling, so indeed it is presented to be provocative, but its flaws are not as you report.

  • My reading suggests typical embedded energy in a car is the equivalent of about 1,000 gallons of gasoline. That's a lot, but only about 15% of the gas the car might burn in its lifetime (YMMV of course.) So it doesn't alter the equation a lot.
  • The roads have embedded energy too, and the roads are used by driving and cycling and shipping food. However, I would like to see good numbers on this embedded energy per vehicle mile or per vehicle.
  • The well-to-tank cost of gasoline is about 18%, which is to say that 82% of well energy makes it into your gas tank after the cost of refining and shipping, according to a variety of sources on this.

So I think even if you factor in car-unfavourable values for all these factors, it doesn't change the equation a lot. The car is not efficient but neither is the agribusiness. I wasn't looking at GHG here, but just fossil fuel energy. We could do a GHG analysys.

Finally in this case I don't think it's that unfair to actually take the simpler view that presumes the person already owns the car, and is deciding between driving and walking. That is in fact how people make the decision. Nobody is buying or not buying a car based on the idea that they would need to eat less food if they drove places instead of walking! The car/no-car decision is based pretty much entirely on much larger factors. Likewise the decision to build and maintain roads is entirely dominated by other factors as well. Can you dispute that?

On the other hand, the fuel burned driving is entirely dependent on the decision to walk or drive. And the fuel used by agribusiness is directly correlated to demand for its food products. If more people walk from time to time for exercise, we will not buy significantly fewer cars or build fewer roads. If people eat less beef, we will farm less beef. But in any event, these factors do not alter things much even when included.

I have yet to see the calories behind producing gasoline in this thread. I mean we are making a big deal of the embodied energy in food but not into the exploration, extraction, and development of the fuel for the cars. This is a one sided argument that fails to consider the variables for both sides in order to make it an equal camparison.

It is noted explicitly, here and in other places. Typical estimates suggest about 82% of well energy makes it to the tank. However, as is also said several times, that doesn't actually figure into the calculations, since the well-to-tank loss is the same for a car as it is for a tractor on a farm or a truck shipping food. It isn't the same for the natural gas used to make fertilizer, but it's small enough that it doesn't affect the equations much.

Hi Brad,

Great post. And you're the first Templeton I've ever met outside my immediate family, so hello.

First of all, everything you say makes total sense to me - nothing wrong with any of the figures or anything in your argument.

This blog is very interesting in showing us that perhaps a 10 mile return commute by foot fuelled by our industrial agricultural systems would be similarly impactful as driving that commute.

Can I just add an extra dimension to the analysis which I think people may find useful in extending the comparison of different modes of transport.

An absolutely fundamental thing about particularly air travel but also car travel, when compared with something like walking or cycling is just how easy it is to do extraordinary amounts of mileage.

This is of course crucial to the 'actual' impact, which is calculated as - (damage per mile) x (miles travelled).

So while I may cycle 10 miles to work and back tomorrow, it is harder to imagine me cycling 5,000 miles tomorrow. Yet if I was restless and I wanted to I could get on an aeroplane and travel 5,400 miles from London to San Francisco in about 18 hours straight.

And if I was the kind of person who drove to work, I think I'd be a lot more likely to move house to somewhere 50 miles from my workplace to save a bit of rent and enjoy the countryside, than if it would mean I had to cycle 100 miles per day!

A thought experiment for you, or if you want (as I have) you can make it a real life process: "How would the choices I make over where I live and what I do change if I decided not to drive a car or use air travel?"

My prediction? You'll cut at least 50% off the miles you travel. Probably more like 80%.

Now that's what I call global cooling!

Matt Templeton

While I find it very interesting how much fuel it costs to grow food, this is a pointless argument, because nobody purposefully eats less (or more) because they will be driving, therefore driving costs more Calories.

If eat 2700 worth of calories for the day and it costs 300 Calories of fuel to drive to the supermarket, it costs me a total of 2700 Calories to walk, and 3000 to drive.

What's required to use the car is for me to offset my own calories, and only eat 2400 Calories that day. Using transport needs people to change their diet, but your article doesn't state this.

Nice set of calculations you got there, but there's 2 minor assumption flaws:
1. People don't automatically eat more when they walk
2. Most people trying to reduce their weight, don't burn anywhere near the commonly accepted burn rates (due to a reduced metabolism). People's body chemistry actually changes when they get below a certain obesity level.

1. The calorie is a measure of energy based on the heat required to increase the temperature of water.
Exploding something underwater and measuring the subsequent temperature change of the water is not in any way analogous to the human digestive system. We have no idea how much energy people extract from foods, nor do we have much of an idea about how much energy people expend for various activities.

2. This analysis assumes that people replace the number of calories they expended walking/cycling. The vast majority of Homo sapiens have large amounts of stored energy to expend.

3. This analysis assumes that agriculture need rely on fossil fuels. Eat local and organic. I ate a bunch of beans today for lunch, probably about 200 kcal worth. I grew them in my backyard without chemical fertilizers or other petrol-based products. It is not difficult to feed oneself without petrol.

4. Does this analysis consider the insane energy costs associated with all of the labor and machinery involved in finding, extracting, processing, and shipping oil? How about the energy costs of building the car and sourcing its materials? The machines used to drill for oil probably run on oil, and the workers operating the machines are probably eating petrol-intensive factory farmed animal products.

5. The author is correct to elucidate how unsustainable and petrol-dependent factory farming is. However, even the most subtle implication that walking may be comparable to driving in energy cost is scientifically irresponsible and epistemologically absurd.

I really like this post, and have referred to it a few times these past years to

We see more and more of "green" logistics stories such as this one:

If I interpret your post well, it might not be so green after all considering that a professional cyclist carrying heavy loads all day long will require much bigger Calories intake to perform well.

I work in Urban Logistics and we know for a fact that a key component to reduce the footprint (both congestion and carbon emissions) of goods transportation is massification. It is indeed much better in all accounts to supply a downtown supermarket with one single 20t truck every other day than with a fleet of 3.5t trucks (900kg of useful load) that come and go 3 times a day. It is also much better to have a downtown large supermarket where people walk to to perform their purchases, than a suburb mall where everyone drives to to get their weekly groceries. That would seem to condemn fleets of small loads on bicycles to perform the logistics tasks that a city needs to live (according to a french survey, 35% of movements are with the intent to move a good rather than a person).

Any thoughts on how you robocar project might help with urban logistics?

What is the energy intensity of the food the cyclists are eating? The numbers above are calculated from US averages, but with an effort you can find food which requires far less fossil fuel to make.

There are other alternatives as well -- natural gas or electric cargo vans, for example, can do a good job if the electricity is not coming from coal. And something even better is coming soon.

Great article! I had no idea tomatoes were used to save all those people!

WE....... are RUNNING out of GRAVITY. Have You heard of GRAVITYY? IF not YOU're taking ADVANTAGE OF IT. I noticed this ONE DAY when I was Running. I started breathing heavier AND ran FASTER AND FASTER than I ever HAve BEFORE. THen I relized WE ARE running OUT of GRAvity. I would LIke to THANK MICHAEL from V-sauce. I love you.

I never realized that. Thank you for teaching all of us that we are taking advantage of gravity. I'm hopeful that in the future everyone will understand and we can live in a more gravity filled world.

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