The trouble with this sort of recommendation is that it would take a large-sample double-blind longitudinal study to generate even weak evidence that the proposal actually increases longevity, and performing such studies isn't remotely feasible. So instead people are tempted to adopt lifelong 'longevity' programs based on speculation and studies that are too weak to generate any meaningful weight of evidence. Rationally, the expected return on investing time in such programs is severely negative - you'll defintely invest significant time and energy trying it out, and the odds of hitting something that works by pure chance (which is all you're really going on) is infintesimal.

For instance, this 'paleo diet' business relies on the idea that eating the same thing our ancestors did in 10,000 BC will make us live longer. But our ancestors lived much shorter lives than we do, we have only weak evidence about what they ate, and anyway 600 generations is more than enough time for evolution to re-tune the human digestive system. So we're left with no particular reason to think this idea is even worth investigating, let alone that the specific recommendations will accomplish anything.