I was on a fitness related board on which we were discussing the issue of grain free and low carb. An RD responded that we absolutely need carbs. Reasoning: glucose is the only fuel red blood cells use and is the preferred food for the brain, Which can adapt to others, but it is unhealthy.
Also whole grains contain antioxidants and b vitamins which cannot be found in other foods.
Now I don't believe this but before I respond to those statements, I would like some science backup. So if you can point me in the direction of some studies or research I would appreciate it. And not Mark's work. With all due respect to his theories, he is not a scientist.