Mark Sisson is a health and fitness expert, and the founding father of the ancestral health movement. A former world-class endurance athlete, with a 2:18 marathon and a fourth-place finish in the Hawaii Ironman World Triathlon Championships, Mark's blog, MarksDailyApple.com, and Primal Blueprint lifestyle program have paved the way for primal enthusiasts to break free from conventional wisdom's diet and exercise principles. Along with his blog, Mark is an entrepreneur presiding over a wide-ranging primal enterprise: The Primal Kitchen healthy condiment line, the educational books and multimedia courses, and a health coach certification company.

Brad Kearns is Mark Sisson's longtime co-author, host of the B.rad podcast, and an elite masters athlete. He broke the Guinness World Record in speedgolf at age 53, is a #1 USA-ranked age 55-59 high jumper, and former US national champion and #3 world-ranked professional triathlete. He lives in Lake Tahoe, Nevada, with his wife, Elizabeth, and enjoys a daily cold plunge in the lake year-round.