Supportive evidence and differences between the Paleolithic diet, Mediterranean diet, and the ketogenic diet?

There is a lot of discrepancy between “diets” such as the Paleolithic diet and the Mediterranean diet when it comes to grains. It seems apparent that there are supportive studies on both sides. Additionally, the ketogenic diet seems to contradict the Mediterranean diet. Does anyone have a good scientific argument that supports one or the other or have an expert opinion?