Oh my God, that's brilliant!! A liposuction doc uses human fat as fuel: http://www.walletpop.com/article/_a/bbdp/liposuction-doc-uses-human-fat-for-fuel/285917 Go get that Double-Double and Big Mac, guys!
So 1 gallon of fat gets 1 gallon of fuel. So for every 8 pounds of fat, you can drive your car 25 miles. But if you wanted to burn that 8 pounds of fat by running, you would have to run 280 miles. So that means that the human body gets 280 miles per gallon.
The key here is the price. How much does it cost for 1 liposuction surgery? Then how much will an equivalent gallon of gasoline cost? Compare the two.