Throwback Mountain Dew (left) and Pepsi (right) have sugar instead of corn syrup, as does Pepsi Natural.

PepsiCo is doing a temporary about-face in its drive to modernize.

Two of its flagship brands, Pepsi-Cola and Mountain Dew, are now out in retro versions. The 12-ounce cans reproduce the brands’ graphics from the 1960s and ’70s, but with the word “throwback” added in a modern sans-serif font. The throwback brands, which are formulated with sugar instead of high-fructose corn syrup, were introduced in late April for an eight-week run.

As sugar-containing products, the throwback Pepsi-Cola and Mountain Dew have something in common with a permanent addition to the PepsiCo lineup: Pepsi Natural. The product boasts an “all-natural” lineup of ingredients, including caramel and kola nut extract. It comes in a sleek 12-ounce bottle with minimalist graphics, and is available in 10 major metropolitan markets.