Why does Carl avoid a double cheeseburger?

W: Carl, what’s it like now? You have been training pretty hard for the Olympics and other major competitions for many years.
M: Well, right now this is my last season. Of course I’m staying in shape to do that. But I’m going to stay in shape. I mean I’ve always been fit so that’s something I’m interested in doing.
W: You don’t want to sit down and have a double cheeseburger? Come on, Carl.
M: No, no.(1)(3 - 1)That’s just because I’ve always tried to stay in shape and I like that, it’s obviously healthy for me as well.
W: Is there anything in the back of your mind that wants you to take part in the Olympic Games again? How old are you now Carl?
M:(3 - 2)I’m 35 , and no, there is nothing in the back of my mind. I’ve gone long enough and now it’s time, I think. For me it’s a lot of fun. But you can’t go on for ever.(2)You can make two choices: you can run until they won’t let you in meets anymore or you can just say this is enough. I decide on the second.
W: Good for you.(3 - 3)And you certainly would be in that competition for greatest Olympian ever with the 9 gold medals.