An unlikely group of stores is becoming a major threat to McDonald's

Convenience stores are becoming a growing threat to fast-food chains like McDonald's.

Chains like 7-11, Wawa, and Circle K are ramping up prepared food offerings, $4 at Nation's Restaurant News.

The convenience stores are getting ahead thanks to a few distinct advantages over traditional fast food chains. Because many of these stores double as gas stations and offer other groceries, they are a one-stop shop rather than a singular destination like Burger King or Taco Bell.

Many of the stores offer a broader assortment than traditional fast-food chains as well, selling everything from pizza and hot dogs to subs and salads.

For instance, Philadelphia-based chain Wawa $4 a full breakfast menu in addition to soups, pasta, hoagies, salads, wraps, and snacks.

Convenience stores are also offering food at cheaper prices than fast-food chains, which are increasingly phasing out dollar menus. The average food purchase at a convenience store costs $2 less than at fast food chains.

The perks are paying off: convenience stores now make up 10% of the quick-service market, NRN reports, citing data from industry research group NPD.

"Quick Service Restaurants really have to pay attention to [convenience] stores," NPD analyst Bonnie Riggs $4. "They're are making inroads and stealing visits from QSR."

Another boon for convenience stores are the customers they're attracting, who are generally younger than those who go to fast-food chains like McDonald's. Visits from 20-something millennials and teenaged Generation Z are increasing all the time.

Attracting younger customers is good news for these chains because many could develop loyalty for life.