Elite athlete, best-selling author and leading proponent of the primal diet, Mark Sisson believes that the lifestyle our primal ancestors engaged in, the food they ate, and the amount of sun they got are still optimal today. On this episode of Health Theory with Tom Bilyeu, Mark Sisson explains how to tap into that primal lifestyle and live an awesome life where you enjoy what you eat, you don’t have constant cravings, and you still burn excess fat and extend your longevity. He talks about the healing power of collagen, the crucial importance of metabolic flexibility, and why there’s no need to sacrifice daily pleasure for good health. This episode is brought to you by: Butcher Box: For a limited time, new members can get 2 pounds of free ground beef in every Butcher Box order by signing up today at ButcherBox.com/impact WHOOP: For 15% off your order, go to https://www.whoop.com and use discount code HT at checkout.  PATLive: Get 10% off your first year of service after a 14-day free trial. Visit patlive.com/impact Indeed: Go to Indeed.com/IMPACT for a FREE $75 credit to boost your job post. SHOW NOTES:   Mark wants people to be pain-free, to enjoy their food, to be able to move around easily [0:24] Mark explains what fulfillment means to him [3:45] Mark and Tom discuss the limits to how much fulfillment money can really buy [4:43] Mark explains why he has evolved to embrace metabolic flexibility [7:54] You don’t need as many calories as you think you do [11:55] How does diet change the number of mitochondria? [13:51] When your body gets good at burning fat, hunger and cravings start to disappear [19:54] The brain’s usage of calories throughout the day does not vary much [24:32] Mark explains why animal protein is better than plant protein [28:21] Mark talks about why you need to eat nose-to-tail for ligament health [31:51] Mark explains why collagen peptides are so important [36:04] You cannot get everything you need from a plant-based diet without supplements [39:07] Mark argues that there is no one right answer for diet [44:03] Mark is unwilling to sacrifice daily pleasure simply for marginal additional longevity [48:18] Mark wishes he could spend the rest of his life eating peanuts and drinking beer [50:30] Mark feels that the coronavirus pandemic has been utterly mismanaged [52:19] Mark prioritizes Vitamin D over even exercise [56:45] Mark and Tom discuss energy drinks and whether they work on a regular basis [1:01:43]   FOLLOW MARK:   WEBSITE: primalblueprint.com/  INSTAGRAM: instagram.com/marksissonprimal/  FACEBOOK: facebook.com/marksissonprimal/  TWITTER: twitter.com/mark_sisson