For the last few days, I have been riding my bike to work. I'd like to say this is a choice I have made for health and wellness reasons, but I won't deny that there are economic factors weighing in far heavier than any desire to stop being such a fatty. Well, I guess being a fatty weighs in heavy too, but in a different way.
Apparently there is some rumor going around that riding a bicycle is actually less efficient than driving a car. People argue that the amount of food (extra food?) you have to eat to propel yourself around town via pedal is enough to offset any money you would save. At least, that's what I got from skimming over the argument. That's right, I didn't even dignify it with a "peruse."

A few people have done the math and discovered that this, of course, is not the case. I want to go one step further in the same spirit as my "True Cost Of SMS" article and do some really elementary math (as it is all I am capable of) on the subject.

So first, let's compare fuel sources.

A car requires gasoline. As of today, the average price for a gallon of gasoline is $3.80 and will propel you, on average, 25 miles. The average driver racks up 12,000 miles per year or 32.8 miles per day. In what is probably the most advanced math ever featured on these pages, that comes out to $4.99 in gas per day.

If you want to get down to it, a gallon of gas contains about 31,000,000 calories (ref). If we could live off of gasoline, it would be the cheapest food in existence. The daily recommended caloric intake for humans is 2,000-2,500. According to the United Nations, the average American actually consumes something more like 3,770 calories per day (ref). No wonder we're a bunch of fattys.

So first let's get the most obvious statement out of the way: Humans are much more efficient then cars.

The average American eats the number of calories contained in a single gallon of gas every 8,223 days. That's 22 1/2 years. $3.80 for 22 1/2 years worth of food? Suddenly gas isn't sounding so expensive! To put it another way: One gallon of gas could power a human for over 22 years, or a car for 30 minutes.

But, since we can't eat gasoline and we're talking about daily costs, that's not really a fair comparison.

So we're spending $4.99 a day on gas, how much are we spending on food? A lot less than you might think, actually. According to the Buereau of Labor Statistics and their 2004 report named "blah blah blah something really boring;" the average American spends $6.33 a day on food. That's $3.67 on food at home and $2.67 on eating out, in case you're wondering (ref).

So, if we trust the math we are spending $6.33 on 3,770 calories of food per day. To answer how much it costs in terms of food to ride your bike to work, we'd have to know how long it takes you to get to work. For me, it's about 3 miles or 15 minutes. But feel free to do your own calculations.

Alright, so biking along a flat surface for one hour will burn 441 calories (ref). That means I'm burning about 110 calories to get to work. Let's also add in the return trip, bringing us to a total expenditure of 220 calories for my trip to work and back.

Applying our math from above we find that every penny we spend buys us about 5.95 calories worth of food. Some simple division (well, simple for a calculator anyway) tells us that the cost of the 220 calories I need to ride my bike to work and back is $0.37. Here are is a table showing these results:

Roundtrip Cost of Riding Your Bike To Work If it Takes You...
30 Minutes (6 Miles): $0.37
60 Minutes (12 Miles): $0.74
1.5 Hours (18 Miles): $1.11
2 Hours (24 Miles): $1.48

To compare that to driving:

Cost of Driving Your Car To Work (Assuming 25 MPG and $3.80/gal)...
6 Miles: $0.91
12 Miles: $1.82
18 Miles: $2.74
24 Miles: $3.65

In real world examples, I think you tend to use up a lot more gas simply because you're sitting there in traffic, starting and stopping, and generally getting much worse gas mileage.

Also, if you're the average American you probably have some extra calories stored away and could ride your bike to work plenty before ever having to spend an extra dime on food. Speaking of which, people who drive cars also have to eat - meaning that you're paying for food anyway - you're really not spending anything more than you would anyway by riding your bike, bringing the actual "cost" to virtually nothing (except the feeling that your insides want to be on the outside).

I also didn't add in the costs of buying your car, taxes & registration, maintenance costs, or repairs. Let's just say that driving a car is not an efficient way of getting around, although it is highly effective in terms of speed.