Live like my great-grandparents, even though we don't have to anymore.
Do physical work, even though it is no longer necessary. I've always run or bicycled 3 to 4 times a week since the US Army trained me at summer camp. Now over age 60 muscles deteriorate if not used, so I've started doing pilates exercises plus lifting a weight, or in winter go to the gym. In the gym I can do rowing and use an arm machine to get in 25 minutes of aerobic exercise without using my knees which are painful in some weather. In summer I saw up and carry off tree limbs at my country property, and ride the 27 miles out there on my bike, carrying groceries. See Dr. Cooper Aerobics and subsequent medical reports of the heart and brain benefits of aerobic exercise. At my age and condition, playing piano is mildly aerobic, although the pulse is only 90 or so doing that. Regular pIano players often live to be very old with good brain function.
Eat like my great grandparents. A serving or two of cheap vegetables two meals a day, sometimes fruit, use meat only as a condiment. I eat maybe an ounce of meat two meals a day, tuna fish about 1/3 of those meals. Vegetable fat two meals a day, usually sugar and salt free peanut butter with sugar free jelly on fructose free bread. An ounce of cheese on corn tortillas two meals a day. Cooking fat and margerine on some breakfasts is olive/canola oil. For a summary of modern health studies see Dr Furman Incredible Health and Michael Pollan, both of whom have done PBS documentary programs. I didn't buy the books. Since cutting sugar use to <5 g per meal and switching fat intake from meat to vegetable, I've lost 40 lb, dropped chloresterol numbers 40 points, and some years don't require pills (never shots) to control the diabetes which happend age 58. I don't restrict calories, or carbohydrates. I do eat a dark chocolate sugar free candy after most meals.
No eating between meals, cleaning the teeth properly is a powerful disincentive to snacking. Brushing, plus scraping the gums with a tooth pick, then flossing, keeps the dentist from drilling so often and keeps the gum loss numbers down. (I have *****y teeth & gums; my ancestors all had dentures after the fifties, my Dad had all but 6 teeth pulled by the Army when he joined).
Stay involved. Now that I'm retired I get out and do volunteer work, and attend a church. I meet new people, I try new tasks, do new things, and some old ones that I'm particularly good at. I watch some TV and play with the internet some, but not more than 4 hours a day. Use your brain or lose it. One old uncle walked down the mountain daily to town (and back) , and did food charity work with his church until he died of cancer age 97. Another uncle is 98 and takes care of his great grandchildren with his wife in his house like a free day-care center. I respect their choices. Other heroes are Bill Monroe, that I saw dancing and playing mandolin on stage the year before his death at 86. He hobby farmed with mules.
Topic: what do you do to keep yourself healthy