Heidi M. Williams, MPH, RD, CSSD, LD, NSCA-CPT. Heidi is a Registered Dietitian, Certified Specialist in Sports Dietetics, Certified Personal Trainer, and Mad Dogg Spinning Instructor. She has been teaching spinning since 2013 and focuses her rides on intervals and climbs to increase strength, endurance, and cardiovascular health. Heidi brings a ton of energy to her rides and has been known to be very motivating. When not teaching spinning, she is meeting with nutrition and fitness clients through her private practice, Real Nutrition and Fitness, LLC. Heidi is also an ultrarunner, triathlete, outdoor fitness instructor, and cross-country cyclist.