Kind of a deep one but here goes -
If you reflect on it, what is the motivating factor behind your healthy eating?
Do you secretly hope that by eating well you'll postpone the Grim Reaper?
Are you trying avoid the slow, steady health decline many associate with old age?
OR, are you trying to live life to the fullest?
And finally (most morbidly) - have you got an age in your head that you'd like to live until?