There's no guarantees for a long life but I think the more important issue is quality of life especially later in life.
I'm now 54 and in an age group that a friend told me was "snipers alley", when I lamented at losing 3 friends of the same age over the last 3-4 years.
I surprised myself by giving up booze about 4 years ago and that helped my health a bit but not as much as a more recent change I made.
About 2 years ago I started getting health issues, minor at first, then more worrying which lead to specialist consultations, MRI's etc etc. Expensive.
Nothing was found that was obvious and it drew a blank while my list of symptoms continued to pile up and worsen.
I got a bit frustrated with the medics who just kept trying different drugs on me to see if anything had an effect.
Now I've never been a fan of the creepy google profiling that knows you better than you know yourself but one day youtube stuck a video in front of me that looked interesting. I'm not going to plug the Dr who made it, so this doesn't look like a promo, but he talked about the problems with sugar and the symptoms of diabetes 2.
Every one of the symptoms he described matched mine. Went back to my quack who tested me but it came back negative for D2.
I decided to quit sugar. Good grief. Giving up booze was easy, real easy, but giving up sugar and trying to avoid it. It's crack cocaine.
However 2 weeks after quitting sugar all my symptoms had almost entirely disappeared.
It's been just over a year now and I've never been as healthy and fit as I am now. All my health problems have gone.
My weight dropped dramatically. I carry no excess body fat and my BMI is around 21.
I've taken up football again and can play with guys 10-20 years younger than myself and I make most of them look unfit.
The addiction to sugar hasn't gone, I had a bit of a craving for booze when I quit that, last a few months, but now I never think of it. No interest in it.
But with sugar that craving is always there, the temptation I sometimes have to endure is enlightening. Makes me realise how hard it is for drug addicts to quit.
I don't believe it is just "cutting calories", but specific calorie sources that need cutting, but that's just my personal experience.
I might not live a long life but I'm now enjoying a quality of life I hadn't enjoyed previously.