A gallon of Gasoline contains 31,000 calories. This can carry 1 human for 914 miles. However, it is poisonous to humans. If you're a robot, try out this option.
A gallon of Vegetable oil contains 31,744 calories. This can carry you for around 933 miles. Vegetable oil is not poisonous.
Test your fuel efficiency by drinking a gallon of vegetable oil.