When it comes to longevity, genetics play the biggest role as we've seen in the Blue zones (regions of the world thought to have a higher than a usual number of people who live much longer than average).

The rest comes down to many MANY different things — what the people choose to eat, how much physical activity they get, how they socialize, what traditional medicines they use, and so forth.

It's naive to think that fasting can make a big difference. Plus, autophagy (IF lovers love to throw this term around) happens in any diet that puts you in a calorie deficit. Autophagy is the result of calorie restriction, not fasting (Anton and Leeuwenburgh, 2014).