William H. Dietz is the Director of the Division of Nutrition, Physical Activity, and Obesity in the National Center for Chronic Disease Prevention and Health Promotion at the Centers for Disease Control and Prevention (CDC).

Prior to his appointment to the CDC, he was a Professor of Pediatrics at the Tuft's University School of Medicine and Director of Clinical Nutrition at the Floating Hospital of New England Medical Center Hospitals. He received his B.A. from Wesleyan University and his M.D. from the University of Pennsylvania. After the completion of his residency at Upstate Medical Center, he received a Ph.D. in Nutritional Biochemistry from Massachusetts Institute of Technology.

He has been a councilor and past president of the American Society for Clinical Nutrition, and past president of the North American Association for the Study of Obesity. From 2001-2003 he served as a member of the Advisory Board to the Institute of Nutrition, Metabolism, and Diabetes of the Canadian Institutes for Health Research. In 1995 he received the John Stalker award from the American School Food Service Association for his efforts to improve the school lunch. Dr. Dietz served on the 1995 Dietary Guidelines Advisory Committee. In 1997, Dr. Dietz received the Brock Medal of Excellence in Pediatrics from the New York Academy of Medicine. In 1998, Dr. Dietz was elected to the Institute of Medicine of the National Academy of Sciences. In 2000, he received the William G. Anderson Award from the American Alliance for Health, Physical Education, Recreation and Dance, and was recognized for excellence in his work and advocacy by the Association of State and Territorial Public Health Nutrition Directors.

In 2002, he was made an honorary member of the American Dietetic Association, and received the Holroyd-Sherry award for his outstanding contributions to the field of children, adolescents, and the media. In 2005 he received the George Bray Founders Award from the North American Association for the Study of Obesity. In 2006, he received the Nutrition Award from the American Academy of Pediatrics. He is the author of over 150 publications, and the editor of four books, including A Guide to Your Child’s Nutrition.