McDonald’s is sharing details of a major turnaround plan. The company recently said it plans to reassert itself as a “modern, progressive burger company.” This at a time the fast-food giant’s global sales were down 2.3 percent in the first quarter.

But can a fast-food chain with 36,000 restaurants worldwide adapt to changing consumer tastes without confusing people? McDonald’s wants to be a place you can get a double cheeseburger for a dollar, or an artisanal antibiotic-free chicken sandwich. And for a company that big, it’s not an easy switch.

“It’s a little bit like the difference between trying to redirect a huge freighter with a barge or whatever, and a sailboat,” University of Oregon marketing professor T. Bettina Cornwell says. “It’s a large brand with a long history.”

Because McDonald’s is such a household name, she says it feels more pressure to offer healthier items.

Meantime, “you get companies like Shake Shack or Smashburger or Five Guys (that) come along, and they just focus on those hamburgers and fries, Maverick Consulting founder John Knight says. He says healthier items also take longer to make. And with as much traffic as McDonald’s has, every extra second costs money.