The beloved burger, America’s all-time favorite restaurant food, is helping casual dining restaurants increase lunch visits by closing the price gap with quick-service restaurants (Q.S.R.), according to The NPD Group’s Checkout Tracking, which provides omni-channel receipt-based information from the same consumers over time.

Burgers have helped casual dining restaurants level the playing field with Q.S.R.s on price. The average price of a burger at casual dining is $9.02 and is $5.62 at fast casual, according to NPD. However, the gap closes when considering that fries typically come with a burger ordered at casual dining restaurants and need to be purchased separately at fast-casual restaurants at an average cost of $2.89, based on NPD’s Checkout Tracking research. Also compensating for the slightly higher burger price at casual dining restaurants is that consumers are factoring in the value of a full-service sit-down lunch meal.

Burger servings ordered at casual dining restaurants were up 3% in the year ending June 2015 period compared to a year ago, and were the segment’s only menu category to grow in servings. In contrast, burger servings at Q.S.R.s were flat, according to NPD.

“It is an effective strategy on the part of casual dining and other full-service restaurants to menu more burger items,” said Bonnie Riggs, NPD restaurant industry analyst. “Successful casual dining operators offer burgers that meet the tastes of their customers and are priced competitively. As a result, they gain lunch visitors.”

The burger helped casual dining restaurants gain lunch traffic ground in the year ending June 2015 period, increasing by 2%, the segment’s first traffic increase at lunch in five years. Q.S.R. lunch visits increased by 1% in the period compared to one year ago.