Natra Slim Keto Natra Slim Keto tries to imitate the natural body function of ketosis. Ketones are a naturally present in your body as a product of fat decomposition. In absence of insulin, your body is unable to utilise carbohydrates. In moments of energy crisis, your body starts decomposing fats. Fat decomposition leads to ketone deposition in blood. And now these ketones are used as an energy supplement.