Americans keep gaining weight, and cars are losing it. It’s a seesaw battle that’s making it difficult to realize the gains expected by a big push for lighter, more fuel-efficient cars. Federal regulators are requiring 54.5 MPGs for cars and trucks by 2025. But even as the automotive industry goes to extremes to shed weight to meet these rules, heavier drivers are adding unexpected pounds. And that impacts fuel consumption. In fact, the weight gain of Americans is blamed for more than 1 billion gallons of wasted fuel each year. We partnered with Cars.com to develop an infographic that documents the complex struggle between fuel efficiency and passenger weight, and the ways automakers are finding new ways to cut pounds (and even ounces) from their cars.