We’ve known for almost 3 years that growing C. Elegans worms on agar infused with beta-hydroxybutyrate extends their lifespans by 20%
But that is worms. We’re mammals and it’ll take around 120 years to do the same experiment in Humans. But there is a study making it’s way to publication that has done a similar study in Mice models … in fact there might be 2 with very similar experiments coming in the same edition of the same journal from 2 independent studies that knew nothing of each other. Anyway both are likely to be published in the next few months and the headline is a 13% extension in longevity observed in ketogenic mice.
http://aups.org.au/Proceedings/47/6P/6P.pdf
In Australia life expectancy is 80.3 years (male), and 84.4 year (female). So potentially an Australian child born today and ketogenic for life might live an extra 10 years - 90.7 years (male), or 95.3 years (female).