You're going backwards. You want to start with common sense. What do wild humans eat? What have they eaten for essentially all of their existence as a species? Animals and plants. So what should you feed your human? The same. It's true for any captive animal. The closer you replicate its natural diet, the healthier it is. Science and numbers can all be screwed with to support or disprove anything you want. Research is all biased, and just correlation at best. Always start with common sense.
You don't need to prove that flies fly.
Steak, eggs, potatoes - fruits, nuts, berries and forage. Coconut milk and potent herbs and spices. Tea instead of coffee now and teeny amounts of kelp daily. Let's see how this does! Not really had dairy much, and gut seems better for it.