The next time you’re watching the dollars fly out of your wallet as you fill your tank at the gas pump, consider another one of overweight and obesity’s hidden costs. Heavier cars use more fuel, no matter how they get that way. Extra pounds traveling down the road impact fuel efficiency, including the additional weight of a vehicle’s occupants.

That might sound trivial at first blush, but it’s not. Folks at the University of Illinois calculated that U.S. vehicles would use nearly one billion fewer gallons of gas annually if the wave of a magic wand could return passengers to their weight in 1960. Overweight and obesity is costing us nearly $4 billion out of our collective wallets and roughly 47 million barrels of oil dependency. There’s more. The U of I team ran a few models and found that the steady trend of increase in vehicle miles traveled since 1985 is highly predictive of future increases in obesity rate.

The country that prides itself on being driven likely needs to think long and hard about where we’re headed. While we’re at it, let’s step out of our cars and take a look at how to develop more walkable, bikeable, livable communities that create conditions for us to address overweight and obesity’s march. Our next phase of growth should be around health rather than around our waists.