The fountain of youth is regular strength training, cardio, quality sleep, good relationships, indulging your curiosity and learning new things, and a diet high in protein (for the exercise) and plenty of plant based whole foods like leafy green vegetables. You'll delay as many of the diseases of aging as much as you can by doing those things. Packaging their effects in a pill would make you the richest person in his…
While nutrition science is short on proofs, generally everything I've read on the latest science points to a correlation between high protein intake and reduced longevity.
Every study looking at strength training has shown it has huge effects for quality of life and health and strength training requires high protein intake.
That doesn't mean you can't still get the majority of your calories from whole food plant sources.