Did your ancestor look like this?

Blue eyes and dark skin. This is what one of your ancestors may have looked like before the adoption of agriculture, 7,000 years ago, based on a new DNA analysis of a well-preserved skeleton. Here’s some more information about him:
He was probably lactose intolerant and had more difficulty digesting starchy foods than the farmers who transformed diets and lifestyles when they took up tools in the first agricultural revolution.
Washington Post: DNA shows ancient hunter had blue eyes, dark skin
For fans of the “Paleo Diet” and other get-back-to-nature notions, the study brings some good news, suggesting that people carry around plenty of genes left over from their primeval forebears.
National Geographic: Blue-Eyed Hunter-Gatherers Roamed Prehistoric Europe, Gene Map Reveals
The news articles are based on this DNA analysis of skeletal remains from a Spanish hunter-gatherer.
Each one of these changes has metabolically plausible explanations based on the metabolics of ketosis. I am not the only one to report these changes. My relations and friends who have gone keto report many of the same, especially skin health. So we all establish an existence proof that at least some people do not need more than 10% of calories from carbs. (I do have avocado, nuts, leafy greens, Brussels sprouts, etc., which have some carbs, so it is not zero, but it is under 10% of calories). The real issue is why do many people lack the metabolic flexibility to adapt well to a different principal source of energy.