Some things that are also just as important as calorie restriction.
Don't drink Alcohol or smoke. What I've noticed is that people who avoid alcohol seem to stay much more coordinated into their older years. I would avoid it 100% to be honest, studies have shown that even small amounts of alcohol are bad. The simple reason why its so bad is that it literally kills your cells and poisons your body. The cells it kills have to divide to replace the cells it killed. It just wrecks your body. What I notice is that many people who are heavy drinkers seem to be uncoordinated drunk even when they are not drinking. This is probably because of the alcohol permanently damaging the cells in the brain.
Sleeping is also extremely important. You have to really make sure you are mostly getting good night sleeps. This means if you have a job that is causing you not to sleep, you have to make changes. There are so many studies that discuss sleeping and how it will premature age you if you don't get enough. It also wrecks your brain when you constantly cut back on it.
Avoid loud noises. You have to stay on top of your hearing starting at a young age. After being annoyed with old people who can't hear, I decided to look up if hearing loss is inevitable with age. What I found is it is not. There were studies that showed that old people living in indigenous tribes without loud noises kept 90% or more of their hearing even at old age. This study showed that most people lose their hearing because of loud noises. What does this mean? Avoid head phones and always wear ear plugs in concerts. Keep the volume at lower levels. If you want to extend your life then you should also worry about things like this if you want to have a decent quality of life.
Avoid exercise for the most part, especially as you get older. Everyone disagrees with this but if you are skinny and on a calorie restricted diet there should be very little reason to exercise. Being skinny will not limit you to your chair and you will get more than enough by every day activities. Doing exercise is usually damaging to the joints, and over taxes your body. Running is the worse, any impact exercises are also very bad.
My brothers friend was always doing all this exercising, I told him constantly that he is crazy and he is going to wear out his joints. A few years later he had knee problems, gut problems, and now can not do a thing. Your body is like a machine, over use it and you will wear it out faster. I don't exercise, but I can easily go and run a mile or 2 miles because I'm skinny and fit from just being active with my everyday life.
Another example was I got a job that demanded me to move around a little too much, and climb many stairs. My daily footsteps went from like 6,000 a day to 15,000 average. I never felt worse in my life and I started to get right knee pain. I had no energy, I felt like I was literally getting old. Now that I got layed off, I'm starting to feel much better, my knee pain subsided and my energy is returning. I always feel best when I stay inactive, my joints feel great and my energy levels are there.
If you feel like you have lots of energy, just sit back and relax, don't feel the need you have to exercise because the experts say that is healthy. Enjoy the energy and keep it by staying inactive.