The big difference between being 40 and 60 is the amount of time you need to put in to staying healthy, fit and strong. Admittingly after your early 30’s was when I first noticed weight gain on the same diet but it was very easy to turn things around. In my 40’s staying in shape just took a little bit more effort. Now at 60 it takes a lot to lose weight, keep it off as well as not losing muscle let alone gaining some.
I think this is why so many people as they get older get so out of shape and unwell. We get away with it for decades and when we start to decline we hang onto bad habits that we shouldn’t have done in our youth We also live in a very lazy society. We take the car for short outings that we could walk, we don’t use the stairs and most don’t even mow their own lawns any more. Life is much easier nowadays.
So feeling like you are still 40 or less is very simple but extremely difficult. Eat well. Plant based diet with lots of fresh vegetables. Cut back on fried and try steamed. Plenty of leafy greens and lots of color. Don’t have to go vegan but less meat and more veges. Start walking every day. Relax, enjoy and walk. Somewhere nice. Lift weights. Many ways of doing it. Gym, pilates, yoga strengthening or even dancing. Something that builds muscle mass and retains it.
You may not get a six pack but you will look and feel better. If you are unwell seek professional advice. It is never too late to start getting into shape so start now.