Eat'n Park was the Pittsburgh area's Big Boy franchisee at the time. It was designed to compete with Big Boy Restaurants' Big Boy hamburger. The Big Mac debuted at the McDonald's owned by Delligatti in Uniontown, Pennsylvania, on April 22, 1967, selling for US$0.45 (equivalent to $3.66 in 2021). It was created in the kitchen of Delligatti's first McDonald's franchise, located on McKnight Road in suburban Ross Township. The Big Mac was created by Jim Delligatti, who operated several McDonald's restaurants in the Pittsburgh area. The Big Mac contains two beef patties, cheese, shredded lettuce, pickles, minced onions, and a Thousand Island-type dressing advertised as 'special sauce', on a three-slice sesame-seed bun. It is one of the company's flagship products and signature dishes.

It was introduced in the Greater Pittsburgh area in 1967 and across the United States in 1968. The Big Mac is a hamburger sold by the international fast food restaurant chain McDonald's.

†Percentages are roughly approximated using US recommendations for adults.

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