September 10th 2019
A couple of years ago I was reading a Michael Pollan article about how much fossil fuel it takes to produce human food — Pollan says it takes 10 fossil fuel calories to make one human food calorie. The idea struck me that it would be possible given that 10:1 ratio to calculate how many gallons of gasoline it takes a person to walk. So, I built HumanMPG.com. The average American gets about 44MPG which is better than the 25MPG that the average car in the United States gets. So it’s probably better for most people to walk than drive.
The 10:1 ratio is a bit messy to evaluate since it takes a lot of things into account, but seems to be pretty accurate. There are a lot of other hard to measure bits of information; some of the questions I still have are outlined on the HumanMPG Results Page.
At rest over 24 hours, your body uses about 1,522 calories. Every hour of the day you use about 63 calories. It takes 3.4 times your resting calorie rate to walk at 3.1MPH; so, every hour you walk you use about 214 calories. Which means that for every mile you walk you use about 69 calories. For omnivores, it takes 10 calories of fossil fuel to create every calorie you eat. So to walk a mile you use 690 fossil fuel calories. There are 30,400 calories in a gallon of gas. So, your HumanMPG is 44.1. Your MPG is better than the average car from 2016 which gets 24.7MPG; so it’s probably better for the environment for you to walk.