Convenience store chains like Sheetz are taking market share from fast-food chains. Facebook/Sheetz Convenience stores are increasingly a threat to fast-food chains like McDonald's.

Chains like 7-Eleven, Wawa, and Circle K are ramping up prepared food offerings, according to Anna Kang 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 one-stop shops 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, the Philadelphia-based chain Wawa offers 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 is $2 less than at fast food chains, according to NRN.

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

Quick-service restaurants "really have to pay attention to [convenience] stores," NPD analyst Bonnie Riggs told NRN in November. "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. Twenty-something millennials and Generation Z teenagers are the first- and second-heaviest user groups, according to NRN.

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