Lol... I don't think he is think much like that. When you get older your metabolism slows down and therefore, it becomes easier to put on weight. As you get older your activity level tends to decrease which also drops metabolism and means that if you continue to eat as your did when younger you're feeding your body too much! When your body will never waste excess energy - it converts it to fat for the hard time.
I think "more than half" is an exaggeration. The media tends to focus on the "beautiful" people which fit a certain profile..often slim. There is a fair bit of pressure placed upon celebrities by the media to be slim too. You will notice that often they publish whole pages dedicated to the even vaguest suggestion of body shape and heaven forbid you should actually walk on the street without makeup!! lol! I remember just recently seeing a four page spread on celebrities who showed a double chin if they smiled or looked down! I can't exactly blame them for wanting to keep out of the spotlight and falling under the pressure. Need to remember also that models and actors need to sustain a certain figure to play the roles that they do... otherwise no work.
I don't condone their behaviours but I can certainly understand it.