Yup, it sure is healthy. Otherwise I wouldn´t be moving towards zero carb diet. Our ancestors fat mostly consisted of saturated fats. Our bodies are designed to handle large amounts of saturated fat which will produce ketones when broken down for energy. Although ketones are produced while consuming no carbs, they are perfect food for brain and the heart. Research shows that heart is capable to work 28% more efficiently on ketones than on glucose and brain works well on ketones! I remember that there is a drug for Alzheimer´s that uses ketones to treat/cure Alzheimer.