It should come as no surprise to anyone with any Physics background at all that it takes more energy to move more mass around.
“The obesity rate among U.S. adults doubled from 1987 to 2003, from about 15% to more than 30%. Also, the average weight for American men was 191 pounds in 2002 and 164 pounds for women, about 25 pounds heavier than in 1960, government figures show.”
Using those weight figured combined with statistics on 2003 driving habits, it is pretty straightforward to conclude that about 39 million gallons of additional fuel are used each year for every pound of average weight increase across the US.
So relative to our svelte 1960 profiles, at a gas price of $3.00 per gallon the US is consuming around an extra $3 billion of oil for automotive fuel a year simply because we are getting fatter. And then there’s the issue of airline fuel costs as well, an effect already reported by the CDC.
So if we could just manage to curb our waistlines, we can decrease our dependence on foreign oil. Maybe we could even manage it by driving less and walking more. What a virtuous cycle that would be.