I agree that the quality of carbohydrates is key, as I’ve posted elsewhere and consider to some degree here (see my comment about processed carbohydrates.). For most people, low glycemic load foods like whole non-tropical fruits, beans, some root vegetables and minimally processed grains would be fine. Though I will take issue with fiber as a necessary ingredient for good health. Certainly, on a high carbohydrate diet, fiber is important. But there have been populations (Inuit, Laplanders, Native Americans of the Great Plains) that ate little to no carbohydrates (and thus fiber) for much of the year. In lieu of short-chain fatty acids from fiber fermentation, their intestinal cells would be nourished by ketones.