This important question came up when our editor, Matt Hardigree, upon learning that fat contained a respectable 37 MJ/kg of specific energy, made the leap to the next logical step: could he drive a car powered by the rich, creamy fat in his own love handles? It's a good question.
First of all, I should make it clear that Matt has an absolutely darling figure, and I'm sure he barely has enough lard in him to power a leafblower. But the idea is a solid one. Most Americans seem to be harboring at least a few pockets of undesired flab, and a certain percentage of people do, in fact, choose to mechanically remove fat from their body via liposuction. So the extraction of fat is a known and established technology.
That's half the problem. The other part is burning the human fat as motor fuel, and the good news there is that is also well-understood and very achievable. In fact, it's already been tried, by, predictably, a Beverly Hills doctor who used patient's liposuction leavings to run his Ford SUV (allegedly).
Depending on your willingness to possibly screw up an engine a bit, it's actually easy to run either straight fat in your engine, or a slightly converted version.
To burn fat as fuel, you'll need a diesel, which is an oil-burner by nature. I'd suggest getting one converted to run on biodiesel, as those are equipped with heaters to keep the fat/fuel from congealing, and special fuel lines that can deal with the fats and oils better. You could run the fat raw right into the engine, though the Engine Manufacturers' Association does warn that doing so could cause issues with fuel injector spray patterns, and deposit-based wear and tear issues.
You could also turn the fat into real biodiesel (lipodiesel) via process called transesterification where, essentially, the glycerin is separated from the vegetable or animal fat. This leaves methyl esters (the actual fuel) and the glycerins, which can be used for making soap or probably some weird sex lube or something.
Okay, so we know it's viable, but here's two issues: using stored human fat as fuel is technically illegal, and who wants to have to beg or steal big sloppy bags of other people's fat from lipo center dumpsters? It's not even your own fat! What's the point of that? And, who has the money for weekly lipo sessions just to fuel your car? There has to be a better way.
And I think there is. The key here is we need a simple but effective in-car lipo system that directly transfers fat from a location of your own choosing right into an in-car storage vessel that can then feed that right into the engine. All while driving! Direct flab-to-speed conversion!
Here's what I propose: start with a nice old simple, reliable diesel car that can handle occasional injections of raw, pure assfat. Something like a Mercedes-Benz 300D (or the turbodiesel, for those speed demons that like to hit 60 in insane sub-minute times). We'll give it a standard biodiesel conversion, with fuel heaters and fat-ready fuel lines. We'll add a small tank for the fat at the rear, with a valve to introduce the fat into the fuel lines. A primary tank for either diesel or biodiesel will be used as well, since it's unlikely you'd have enough fat to be the primary fuel source.
The real innovation here is the LipoBelt™. It's a strong belt made out of compressive elastics that houses a solenoid-actuated, telescoping liposuction cannula, along with a small solenoid-actuated syringe to inject a local anesthetic. You'd simply position the belt so the 'action area' was over the area of your fuel/fat storage, belt it in place, and activate it.
Once activated, the solenoid-actuated syringe would inject local anesthetic into the area, and the cannula would incise the area, and begin a back-and-forth mechanical motion (powered by the same solenoid that actuates the cannula) to help break down the fat cells. This is a variant of PAL (Power Assisted Liposuction) commonly used.
A small suction pump under the seat, powered by an inverter off the engine, would pump out the fat into the storage vessel. A timer that the driver can set will automatically stop the lipo procedure to prevent over-liposuctioning. When done, the cannula retracts back into its housing, and the driver (or passenger — the belt will be on a hose that allows use by anyone in the car)can remove the belt at their earliest convenience.
The fat is introduced into the fuel system as soon as possible, to minimize the amount of fat that needs to be stored. Ideally, the fat is burned as it is removed, with the storage vessel only used for overflow. This will help keep the car legal, as the evidence of human fat will be burned as the car is driven as much as possible. Plus, if it's your own fat, who's going to tell?
The older Benz diesel should be able to cope with the occasional fat injections better than a modern, more complex diesel with higher tolerances, but in theory this system could be adapted to modern diesels as well. Still, I'd suggest regular checks for fatty buildup in the engine if the on-board lipo system is used frequently.
Oh, I suppose you may want to consult with a doctor before doing something like this, but they'll tell you you're crazy and never to try it. Because they're in the pocket of the diesel industry, probably! Also, make sure to keep your lipo belt nice and clean and sterile. Wipe it with a damp cloth between uses, or something.
An average outpatient liposuction procedure usually caps the amount of fat removed to five liters. That's about 1.3 gallons, and on a diesel like an old W123 Benz, should be good to take you 30-40 miles. That's enough for your daily commute! For free, and you'll end up with a new, slim, probably somewhat bruised and maybe infected you! This is the best thing ever.
There are some issues. You only have so much fat on you, and it may take up to a year for all your lipo'd fat to come back, and that will still require you sticking to a careful, rigorous cheeseburgers and fried foods diet. You can, of course, get friends and people you find on Craigslist to act as fuel sources for you, which has the added benefit of allowing you to use the HOV lane.
The self-powered fatmobile can be a reality. We just have to dare to dream, and to be sure to hit buffets as often as we can. For science.