High Carb / Low Fat isn't primal but it could be done right persay. If the person stayed away from gluten, oats, and most beans and only used sweet potatoes, organic corn, organic potatoes, fruit, taro, tapioca, and rice it could be done. They would only take in about 300 grams of carbs daily to do it right. And their fat has to be from good sources like coconut oil, avocados, and extra virgin olive oil. They would have to eat organic chicken, pastured eggs, lean grass feed steak, and fish to stay healthy. It could be done, but it isn't ideal.