I have a bit problem with the paleo diet and also the low carb diet that is being propagated by many people including some claiming to be health experts. I believe these diets are extremely harmful to human health and also to the human mind. I have been on both extremes of carnivorous and vegetarian diets and I feel 1000% better on a my current diet which uses a minimal amount of flesh foods (mainly fish). I am not stating that animal flesh is inherently bad for human health; it has many properties that promote health and also properties that destroy health. My main argument is with people who propagate eating large amounts of flesh on a regular basis, this is a terrible recommendation and long-term will destroy health.
As someone who practices Ayurveda, I am very willing to admit that each individual should find the diet that is appropriate for themselves. There certainly will be a very small percentage of the population, probably less than 1% that can thrive very well on a diet high in animal flesh and there will be a very small population that can survive on the other extreme of being purely fruitarian, also probably less than 1% of the population. People that promote these 'fad' diets are probably people that have a specific genetic make-up that allows them to thrive on these extreme diets, but they should never be propagated to the population as a whole as 'the best' diet.