Keto is not meant for long-term use. You will have one miserable life if you could pull that off but i doubt you could even if u tried. It works really well for cutting that last bit of stubborn fat when u trying to show your six pack.
As with anything, it depends. I'm also not suggesting that keto is harmless long-term, just that it's not inherently harmful. Several sections of the Wikipedia article are instructive: en.wikipedia.org/wiki/Ketogenic_diet
