McStroke is episode 8 of family guy season 06. It was originally aired on January 13, 2008.
Peter decides to grow a mustache, but then he’s mistaken for a fireman (because they all have mustaches), so he lends a hand when a fire breaks out at a local fast food restaurant. The owner gives him unlimited burgers as a “thank you” but he eats so many and he eventually has a stroke. When Peter recovers, he vows to expose the fast-food company and becomes friends with a genetically engineered cow he meets after infiltrating the McBurgertown warehouse