According to the Concise Oxford Dictionary, both spellings are technically correct. Though “Ageing” is listed as the primary, at least for the UK. “Aging” is the preferred spelling in the US and Canada. Now we’re not here to discuss spelling, I know. But as long as I have the dictionary open, let’s see what it says…
ageing (also aging) 1 growing old 2 giving the appearance of advancing age
Oxford Concise Dictionary, Ninth Edition
Straight away definition Number 1 isn’t very useful. And as simplistic as Number 2 looks, I think it sums up what many readers are concerned about. Though I’d like to expand a little on it — to make it more relevant to this little journey we’re about to begin. Here is my working definition of the kind of ageing that we are “anti-” …
prematurely giving the appearance of advancing age, due to destructive habits that are contrary to the laws of nature
(Say that ten times fast 
)
This is what we’re here to talk about.
It may sound a rather weighty definition, but it also defines the area over which you have control. And that’s the first thing I’d like you to remember: You are in control. You have the power to steer your own life, your health, anything you want. Some people find that a little scary, but when it sinks in there’s no more liberating feeling than empowerment. Think about it for a while.
