When I run into paleo skeptics, here is one of the techniques I use.
Paleo Skeptic: But really, who’s to say there’s an ideal type of human diet? And haven’t we adapted to a more modern diet?
JLD: Let me ask you a question. What is the healthiest thing to feed infants?
Paleo Skeptic: Uh, breast milk.
Paleo Skeptic: Well, because that’s what’s natural.
JLD: What do you mean by natural?
Paleo Skeptic: I mean, it’s what mammals do. It’s what infants are adapted to. It’s what we’ve done for millions of years.
JLD: Fine, but we’ve evolved since then — and we’ve developed a sophisticated technology called infant formula.
Paleo Skeptic: Yes, but it hasn’t been long enough. And infant formula isn’t as good as the real stuff. Maybe one day we’ll develop a formula that is, but we’re not there yet. And there’s a lot of research that suggests that breastfeeding infants is good for the long-term health of the baby.
JLD: It sounds like you already believe in the general paleo approach, just for a limited window of life.
Paleo Skeptic: …
This example, as described, isn’t a scientific argument by any means. It’s just a talking point.
Keeping that in mind, my point is that there are a number of ways in which many people already believe in this general approach, they just don’t call it paleo. Or they use the same lines of reasoning to justify an organic farmer diet. So just find a way to re-frame their existing beliefs in a new light. That way, they don’t have to change their belief system — something which few people ever do.