NC for this. Sorry, a bit long, but wanted to say enough.
Oh, 57 excellent replies but I have been left hugely disappointed.
One thing and one thing only: State of mind. aka no stress.
I feel qualified to comment and make such a bold statement as I have a mum who has been youthful all my life- she is now nearly 90 but we sometimes have to tell new service people to ignore her (she may take a while to respond to them etc) because she is 'a very old woman'- they fail to see it otherwise! So, we have had a lot of questions since I was in my teens what her secret is, so I paid attention to her. I also admired her as a person.
My mother is happy, kind, wise and does not let anything get to her- nothing!. SO mum is never ever stressed out. Ever. She lost her husband in her early 50s, left to raise 5 kids on her own etc etc, but it is like nothing daunts her. When a grandkid behaved appallingly, she confided in a neighbour, relative whose only remark/ Q was: 'But you have not show any signs of having been through it all with this kid who is close to your heart, for 5 years on now.'
Of course, she and I, are blessed with a good body frame (never examined the face structure for this purpose), eat healthily, are not poor, so all that helps. However, to my mind, the state of mind, no stress and not taking everything to heart.
My eldest sister has extra weight, eats everything, is very pretty, but has, what I would call a challenging career- self-employed- so waking up 4:30am daily. However, she too inherited mum's state of mind. and her fav expression is 'no stress'. She is therefore not aging badly at all.
When we were preparing mum's 60th birthday, many people were shocked as they expected it to be her 40th birthday.
I had a very demanding career but did well and retired early. Even during my most demanding years, I always went to the gym, so was always slim. Fast forward now to being married later in life, work is optional so have all the time in the world; but my husband can sometimes be stressed out with his business: he struggles with II (he has an It person). Any time, I don't let him deal with his frustrations in a measured way, I see, I am getting a bit stressed. And I hate that, as not even my demanding career stressed me out- ok, I enjoyed it and was very good at it.
I would tell him stress would age me and I need proportionality. He just related to frustration- even wifi going down on a lazy Saturday (nothing being impacted) is treated like an end of teh world- in a way you think he was very over indulged as a child. Frustrations are part of life. For example, when I worked and my presence was always crucial- if my 2 consecutive trains got cancelled- annoying, but I just breathe in and breathe out and make a call to whoever needs to know length of my delay is unknown, but will let them know as soon as I get on a train. What's teh point of tearing your hair out etc etc- not that a train will reappear. That kind of thing.
Husband has changed a lot in handling 'daily frustrations' but many people just can't let things be. What you can change- change. What you cannot, ask for wisdom.
IHTH