by Roland Jones
A new study that received a lot of publicity last week contends that Americans are wasting billions of dollars every year on gasoline because of the growing size of their waistlines.
The laws of physics still apply when it comes to driving ? the fatter you are, the fatter your fuel bills will be, as it takes more power to propel you and your car down the road. But before you jump onto a treadmill to lose a few pounds, there might be easier ways to save money at the pump.
?When you start talking about a 1 or 2 percent change [in fuel efficiency], you can get that from a lot of other things, like closing windows and reducing drag, or pumping your tires a little bit harder to reduce rolling resistance,? said Marc Ross, professor emeritus of physics at the University of Michigan. ?It?s a long list.?
The obesity rate among U.S. adults doubled from 1987 to 2003, swelling from about 15 percent to more than 30 percent. At today?s gas prices, that means an additional $2.2 billion squeezed out of our wallets at the gas pump each year, according to the study by Sheldon Jacobson, an industrial engineer and researcher at the University of Illinois at Champaign-Urbana and Laura McLay, one of his doctoral students.
?The obesity epidemic is having an economic impact on fuel consumption,? Jacobson told CNBC last week. ?We often hear of obesity having a health impact, but now we have a socioeconomic impact.?
Only those that deny the laws of physics would say no relationship exists between body weight and fuel efficiency.
The same effect already has been detected in airplanes. Research from the Centers for Disease Control and Prevention has found that heavy fliers have contributed to higher fuel costs, which in turn is eating into profit margins or deepening losses. There has even been talk of charging airline customers by the pound.
Outside experts say Sheldon?s calculations probably are correct but that the impact of body weight on fuel efficiency is only one factor -- drivers might do better to improve the way they drive instead, driving at a moderate pace, braking more slowly, observing speed limits and removing excess baggage from the trunk of their vehicle.
?I think driving patterns could also be significant,? said Ross, the the University of Michigan professor. ?Stopping is really a tremendous fuel user, so one suggestion is anticipate when people ahead are stopping and let your car coast to a more moderate stop instead of braking hard.?
Losing weight would certainly help your fuel efficiency, but a greater responsibility for fuel economy lies with automobile manufacturers, Ross said.
For decades they have lobbied against fuel efficiency standards. But there is still scope for some other fuel-saving improvements, such as regenerative braking ? a feature in the Toyota Prius that recovers energy from braking and stores it in a battery for later use.