Usually, he doesn’t eat the fries. Or anything else, for that matter.
There’s a segment about him in Supersize Me with an interview. He’s not crazy: he’s just a guy who really likes Big Macs. And watches his intake.
McD has (used to have?) a good-sized salad as a standalone dish over here. Healthy! Until you’d pour the Vinaigrette sauce over it, that is. With that Vinaigrette the salad had more calories than a Big Mac. And an ungodly amount of salt.