There was an old guy at a gym I used to go to who came in regularly, and walked on the treadmill, but he did it wearing a full suit and tie, he replaced his suit shoes with trainers but otherwise was fully suited up.
And on the subject of chocolate milk- admitadly I've never been brave enough to look at what's in it, but the Tesco brand chocolate brownie flavour milk is by quite a long way the nicest chocolate milk I've tried.