Product placement is one thing that makes these expensive movies possible, kiddies. Deal with it.
It was a lot less egregious in this movie than in the Reeve movies. The Cheerios cereal box (Cheerios gets a credit at the end of the film, no fooling) that Ma Kent sets out for breakfast actually changes position from shot to shot so what the brand name is clearly visible in each one. And who can forget how they featured the giant illuminated Coca-Cola sign smack in the middle of a fight scene in Superman II?
"Realism is irrelevant in a superhero movie" is a bullshit premise. Bringing as much realistic detail to bear as possible in these things creates a verisimilitude that really helps to sell the fantasy.
Buying a brand-name burger on his way to the press conference at the end of Iron Man
is just about the best thing Tony Stark does in that movie.