Mark Sisson is the New York Times best-selling author of The Keto Reset Diet and best-selling book The Primal Blueprint - which was credited with turbocharging the growth of the primal/paleo movement back in 2009. Mark is the author of several books, including Primal Endurance, The Primal Connection, and other popular lifestyle books. He is also the publisher of MarksDailyApple.com, a top-ranked blog for over a decade in health and fitness categories. Mark Sisson is the founder of Primal Kitchen and Primal Nutrition - where extensive product offerings can be found.  In this episode, we discuss Mark’s thoughts on metabolic flexibility, listening to your body, organ reserve, and also dig into his impressive entrepreneurial journey.