An average human being gets 400 miles perJUN 20 2007

An average human being gets 400 miles per gallon at 3 mph. "A 155 lb human walking at 3 mph will burn 246 kcal/hour, or 82 kcal/mile. Feed that human one gallon of gas in potential energy -- 31,548 kcal -- and he'll have enough energy to walk for 128 hours."

Update: Riding a bike increases the MPG to ~750.