They're gimmick diets. As far as I know paleo is actually just the zone diet from years ago. I know people who those diets do work for, and they're very austere about them, but I think it's a waste of time. Vegans catch a lot of shit for being so vocal about their diet, but as far as I've seen keto and paleo is just as bad if not worse. As an aside, I always think it's funny when people who lift do paleo or keto and think it's the best thing ever. The traditional 40/40/20 always worked, and has worked for people who are definitely stronger than you, why try to reinvent the wheel? Also keto isn't even viable to maintain beyond a year to two as far as I know.