Though it’s complicated to pinpoint exactly what the Paleo, hunter-gatherer, primal, or pre-agricultural diets of our ancestors were composed of (especially since it was highly dependent on where you lived and what you had access too), one thing that is clear — they ate a lot more plants in greater variety and volume than today. Jeff Leach at The Human Food Project considers this to be a critical aspect. Through his work with people following a modern hunter-gatherers’ type diet, he is able to deduce the effect of high-plant-based diets and the resulting effect on the human microbial community even when consuming high volumes of animal products. He believes high fiber content in plants provide substrates for gut microbes to digest and create byproduct that effect various gut metabolic activities including PH balance, gut permeability, immune balance, bowel movements and so forth. Failure to consume high amounts of plants in these diets leads to severe compromise in your gut microbial communities leading to what Dr. Leech calls“a diet that will not be into you.”