We have little to no evidence to support the paleo fad. Human beings have consumed grains for at least 100,000 years.
A physician is not a dietitian or a nutritionist. They are far more qualified. A dietitian requires simply a bachelor's degree in pretty much anything (social sciences is fine) and then a short internship where you learn to repeat what the book says. Nutritionist is just something anyone can call themselves with absolutely no qualifications whatsoever. Picking a doctor over those options is not a red flag.