Frito-Lay has long dominated the snack-food business by relentlessly focusing on the middle swath of America that eats chips and pretzels and party mix without regard to the effect on the waistline.

Now, though, Frito-Lay, a unit of PepsiCo, is building a “company within a company” to pursue what might be called a 1 percent-99 percent strategy: creating high-end snacks as well as those that appeal to what it diplomatically calls “value” customers.

The effort is all about what Tom Greco, president of Frito-Lay North America, has called the “bifurcation” of American snackaholics.

By that, he meant that “the rich are getting richer and the poor are getting poorer,” said Ann Mukherjee, chief marketing officer at Frito-Lay North America.