Co-author of the “Younger Next Year” books, Chris Crowley is a motivational speaker that enjoys an active and healthy life—a perfect foundation for his writings in the series. Jennifer Sacheck, Ph.D. is an active member of the American College of Sports Medicine and the Obesity Society. With her expertise in diet, physical activity and health, she co-authored the latest installment in the Younger Next Year books, “Thinner This Year.”