# Paul Souders vs. a 2008 Subaru Forester

#### (A Quick Back-of-the-Envelope Calculation)

• Pm = price of a gallon of Alpenrose 2% milk at New Seasons = \$3.89
• Pr = price of a gallon (16 cups) of cooked white rice at New Seasons = \$0.35
• Dfg = mileage of our 2008 Subaru Forester (standard transmission) during a typical week of commuting = 24.5 mpg
• Eg = energy equivalent of a gallon of gasoline = 31,000 kcal (aka “calories”)
• Em = energy equivalent of a gallon of 2% milk = 1952 kcal
• Er = energy equivalent of a gallon (16 cups) of cooked white rice = 4256 kcal
• p = energy I burn in one hour riding my bike on a flat road with no wind at 15 mph = 704 kcal
• Dpg = my mileage if I could somehow consume a gallon of gasoline = (Eg/p) × 15 = 660.5 mpg
• Dpm = my mileage on a gallon of 2% milk = (Em/p) × 15 = 41 mpg
• Dpr = my mileage on a gallon of cooked white rice = (Er/p) × 15 = 90.7 mpg
• Cfg = cost to drive the Forester one mile = Pg/Dfg = \$0.17
• Cpg = cost to ride my bike one mile if I could somehow consume gasoline = Pg/Dpg< \$0.01 (greater than half a significant digit [\$0.005]
• Cpm = cost to ride my bike one mile powered by milk = Pm/Dpm = \$0.09
• Cpr = cost to ride my bike one mile powered by rice = Pr/Dpr< \$0.01 (less than half a significant digit [\$0.005]

#### Notes

 Assumes 2 cups of cooked rice = 1 cup dry rice weighing 8oz
 A pretty leisurely speed for me under those conditions, so I might actually burn fewer calories than this, i.e. get better “gas mileage”