McDonald's is making a change to its McMuffins and biscuits

McDonald's is making a change to its breakfast menu.

The fast-food chain is getting rid of margarine and swapping it for real butter on its McMuffins, biscuits, and bagels, CNBC reports. McDonald's hasn't responded to a request for comment.

McDonald's has also been tweaking how it cooks and prepares its burgers.

The fast-food chain has increased the size of its quarter-pounder beef patties from 4 ounces when raw to 4.25 ounces, according to the company's website.

The 4-ounce patties shrink to 2.8 ounces after cooking.

McDonald's also recently revealed that it would be toasting its buns for an extra five seconds, making them 15 degrees warmer, and changing how the beef patties are seared and grilled in order to make them juicer.

"These little things add up to big differences for our customers," McDonald's CEO Steve Easterbrook said at conference in May in New York, according to Bloomberg. "We're recommitting to tastier food across the menu."

McDonald's is making major changes to its menu and business following seven straight quarters of same-store sales declines in the US, where the chain is battling a pervasive public perception that its food is processed and unhealthy.

The company has also been hurt by a series of food-safety scandals in Asia, which contributed to a 15% loss in net income last year.

Meanwhile, McDonald's relationship with franchisees, who operate 81% of its restaurants globally, is at an all-time low. Employees have also been striking for higher pay and better working conditions.