If you want to live to 95 and still be as spritely as Jack Lalanne, here's what you need to do, per the book The Longevity Prescription.
1. Eat minimal saturated fats. Eat 2-4 servings of fruit and 3-5 veggies, and unprocessed grains, beans or other fiber-rich foods daily.
2. Exercise 5x a week: 2 resistance + 3 aerobic sessions
3. BMI under 25.
4. Sleep soundly 7-8 hours a night and nap 20-30 mins a day.
5. Be in a marriage with someone you trust and love and are intimate with.
6. Get on with your kids, siblings and extended family.
7. Maintain active long term friendships with people you care about.
8. Interact daily with people, in person, by phone and online. Go out 3x a week with friends or family.
9. Make 1+ new friend a year, and communicate regularly with them.
10. Avoid depression and anxiety, don't relive unhappy moments and maintain a hopeful attitude for the future.
11. Challenge yourself to learn new things.
12. Keep up with events, consume media, and know what's going on in your community.
13. Find simple joys in life, and laugh heartily.
14. Stretch your mental muscles regularly; reading, games.
15. Don't harbor grievances, adapt, accept losses and look to new challenges.
16. Employ stress reduction strategies; yoga, golf, meditation etc.
17. Recognize the good in aging; wisdom, experience, perspective and patience.
18. See the doctor regularly for checkups and tests.
19. Take a multivitamin and a children's aspirin daily (81mg).
20. Take prescribed medication as directed.
21. Do self-exams; breast and testicular lumps, moles and birthmarks
22. Get glasses or a hearing aid if you need them.
23. Wear a seatbelt and bicycle helmet and use sunblock.
24. Don't smoke.
25. Drink alcohol only in moderation; men 3 oz, women 1.5 oz a day.
I've read a few books on this subject now, and this sums up the best knowledge we have so far. As much as this is a recipe for longevity, its also a GREAT recipe for an enjoyable life. The point here is youth extension, as much as life extension. There's a big difference. Who cares about living to 90 if the last 20 years find you fighting illness constantly. Live life like LaLanne, actively, with purpose and with people who you love around you.
Here's some more advice from Methuselah Foundation longevity experts.