In the endless quest for better efficiency in our trucks, a new route has appeared on the map. People call it “lightweighting,” and it’s become increasingly central in efforts to meet mandated fuel-economy performance in the coming years, for cars and trucks alike. Especially cars.

I’ve seen this called “the storm of lightweighting” and a “revolution in materials and processes” as manufacturers such as Ford, GM, and Volkswagen test this innovation and that, throwing first-tier component suppliers into a tizzy trying to keep up. Both the U.S. and Canadian governments are funding lightweighting research with millions of dollars. And I’ve been shocked to realize how many lightweighting conferences there are — dozens a year.

Late this year we’ll see one result of it all: Ford’s 2015 aluminum-body F-150 pickup.

Fully 97% of the truck’s body is aluminum, which sits atop a new high-strength-steel frame that’s said to be stronger than ever. And how much weight is saved? About 700 pounds out of a 5,000-pound truck, some 14%. Not bad.

But is any of this actually new? Well, not really, at least not in our world of big trucks and long trailers.

Remember, it was in the late 1930s that Leland James, then president of  Consolidated Freightways in Portland, Ore., wanted truck makers to build truck components with lightweight aluminum instead of traditional steel. None of them bit on the idea, so he hired some engineers and built the trucks himself, later through the Freightways Manufacturing Company in Salt Lake City. It changed its name to Freightliner Corp. in 1942. Those first cabover trucks were both light and durable, and pretty much an instant success.

More than 70 years later, the idea of increasing payload by lightening the truck is pretty routine, though it’s been gaining traction in recent years as profit margins have been squeezed. So most truck manufacturers have lightweight packages in their databooks that include things such as aluminum crossmembers, hubs, wheels, and tanks. A single exhaust stack instead of duals. Maybe a fixed fifth wheel, not a slider. And of course 700-800 pounds can be trimmed away by going to wide-base single tires.

All these options will become increasingly necessary as fuel-economy mandates get more stringent, so you’d better get used to ’em. And, unfortunately, in most cases get used to paying more for them up front.

Smart truck operators also watch their fuel load and nowadays often spec smaller tanks than they used to. Diesel fuel weighs about 7.5 pounds per gallon, so it’s not a small factor in the overall lightweighting game. A full 120-gallon tank carries about 900 pounds worth of fuel, whereas a pair of 150-gallon tanks tips the scales at a whopping 2,250 pounds. That’s a lot of payload to be gained if your hauls allow it.

And there’s one more surprising angle to pursue here, which never, ever seems to enter the equation: the weight of the driver.

A while ago I came across a stunning article that referred to a blog on the Allstate Insurance website (it’s no longer there, so I can’t offer a URL).

The gist of it was this: steadily rising obesity rates (35% of Americans now self-identify this way) are having a negative effect on passenger car fuel economy — an extra billion gallons of gasoline consumed every year, on average, between 1960 and 2002.

That’s non-commercial vehicles, but you know how much effort goes into saving 62 pounds on a fifth wheel, for example. Not to mention many thousands of dollars in engineering costs. Yet it’s so easily outdone by a succession of three-buck cheeseburgers.

Makes you think, no?