As someone who follows life extension research closely: all the lifestyle stuff like "eating less" is useless. You can't rejuvenate an organism by changing the external inputs to its natural processes. It's half-measures at best.
I’ve personally starved and seen worms live much longer than they normally do, and regularly found worms in plates months after they should have all died. There’s nothing unnatural about an organism going into “survival” mode when food becomes scarce. It’s clearly something that benefits a species survival.
People want the holy grail, literally. Eat pizza, drink beer while sitting playing video games and take a magic pill that makes you young again.
For anybody interested, the mTor pathway is really interesting in this regard, and in general the effects of AMPK on cellular metabolism. TLDR is that in the modern world most people never activate these pathways (since we're always in a fed state). Ostensibly there will be some breakthroughs when we finally learn why these starvation pathways are so beneficial. Inflammation seems a decent guess - eating increases it, and fasting decreases it, as a general rule.