The comments were lobbed across the common table at the local taproom:
How many miles per gallon do you get on your bike?
Is it really that efficient to ride a bike?
And so on and so forth. The topic of conversation was the next step in the #myPersonalParis evolution. In order to reduce my personal emissions of greenhouse gasses I have set the goal of riding my bike to work three days a week through the fall. Sixty percent of my commuting trips by bike might seem a little aggressive, but I feel that doing more than half will be a sort of tipping point in my daily behaviors. It’s a theory and I am going to test that theory in practice.
The miles per gallon question is a constant because there is always some smart ass in the room who says, “You aren’t carbon free because you are breathing.” Sure enough, but I had to be breathing anyway so I consider that a moot point.
However, let’s spend a moment to ruminate on the relative efficiency of riding a bike to work versus commuting in my truck.
A gallon of gasoline contains 7,594 kilocalories of energy and a gallon of e85 contains 5,463 kilocalories of energy.  On average my truck—a Ford F-150 equipped with a flex-fuel V-8 engine—achieves 15 miles per gallon using e85 fuel. Simple math says that my truck uses approximately 364 kilocalories to travel one mile.
What about the bike. Based on over 1,110 miles of riding tracked via a Garmin vivoactive HR the kilocalories expended to travel one miles via a bicycle is approximately 65. The range is anywhere from 60 to 75 with the high end representing some serious pedal mashing on a long distance ride.
Based purely in terms of kilocalories the bicycle is around six times more efficient just to transport myself from point A to point B.
How does that translate to miles per gallon? I do not care because I am not fueled by gasoline. Beer on the other hand? The average pint of beer—not the light lager swill—contains 200 kilocalories. A gallon therefore contains 1,600 kilocalories.  Therefore, I achieve approximately 25 miles per gallon beer equivalent or MPGBE.
It’s a ridiculous comparison, but sometimes we need a little folly.