Not saying this guy isn't a quack, but I have seen studies (or articles about studies, at least) by reputable universities on low calorie diets that suggest they increase your lifespan.
I can't recall the details, but if you're interested, start googling - it's a legitimate field of study with some surprising outcomes (to a layman like me, at least).
My impression is that everyone is dialing back their excitement over those results. They were based on rats, they failed to hold up for primates and almost certainly will shorten lifespan for humans.
I can't recall the details, but if you're interested, start googling - it's a legitimate field of study with some surprising outcomes (to a layman like me, at least).