Nope, wrong. Genes associated with diet have been among the fastest-evolving amongst humans and are still being actively selected for today. For instance, genes for lactose tolerance have independently evolved 3 times in the last 10,000 years amongst three separate pastoralist populations. Likewise, in the Inuit, biological adaptations to the high fat content of a traditional diet that was mostly or all animals are found, and these adaptations developed within the last 3,000- 4,000 years.
Whether the evolution in this case is within the human genome itself or within commensal gut microbes is irrelevant
What does that mean? It means the assumptions of the paleo diet, humans haven't evolved in 100,000 years crowd are entirely wrong.