There are about 30,000 calories in a gallon (about 4 liters) of gasoline, which is enough to power a person for about 20 days, depending on their caloric intake. Humans burn energy pretty efficiently. In fact, the average person going about 15 miles per hour (about 25 kph) on a bike could get more than 900 miles per gallon (almost 400 kpl) riding on a bicycle if they were able to fuel up with gasoline.
More facts about energy:
- Vegetable oil actually contains about the same amount of calories as gasoline, so if the human body needed only fuel, not nutrients, then you could just fuel up with a few gallons of vegetable oil every month and be done with your eating for the month.
- On a chemical level, gasoline and vegetable oil are pretty similar. Both contain long chains of hydrogen and carbon, making it possible to convert vegetable oils for use in some cars.
- Fuel efficiency in humans decreases rapidly with speed and its accompanying air resistance. For instance, in the bicycle example, going even 10 mph faster reduces the miles per gallon by about two-thirds.