This a play on words, this food pyramid contains real, whole, fresh food not manufactured food particularly seed oil products. You can see that the focus is on healthy fats and protein, and really the only carbs are found in leafy green vegetables, full fat dairy, nuts and red berries. Carbohydrates are not essential for life and we can exist without them. Our body, including the brain and heart, functions more efficiently on ketones derived from the saturated fats in our diet. These ketones are made in the liver from our food; taking ketone supplements are not really effective because they are often taken in addition to our usual diet leading to weight gain. On a ketogenic diet we only maintain or lose weight when fat is the biggest component of what we eat. When carbohydrates is present with fat the insulin response to those carbs will lock away fat, carbohydrate will be used in preference by the body and fat is stored rather than used. Ketone production stops.