Mark is a leading authority on nutrition and wellness, and the author of the New York Times bestselling book Body Confidence. As founder of the Venice Nutrition Program—which has been licensed by hundreds of health facilities, doctors’ offices, fitness studios, and health professionals nationwide—Mark knows what it takes to lose weight the right way and achieve life-long body confidence. He opened the first Venice Nutrition Consulting center in Venice Beach, California, more than a decade ago, and it has since grown to more than 500 centers throughout the U.S.

Macdonald is a regular contributor to CNN/HLN and Dr. Oz, a National Ambassador to the American Diabetes Association, Chair of the International Board of Nutrition and Fitness Coaching, and a top presenter for IDEA, the world’s largest fitness organization.