Dr. Klein is the William H. Danforth Professor of Medicine, Director of the Center for Human Nutrition, Director of the Center for Applied Research Sciences, Chief of the Division of Geriatrics and Nutritional Sciences, and Medical Director of the Weight Management Program at Washington University School of Medicine in St. Louis, Missouri. Dr. Klein received an MD degree from Temple University Medical School and an MS Degree in Nutritional Biochemistry and Metabolism from the Massachusetts Institute of Technology. He completed residency training in Internal Medicine and a Clinical Nutrition fellowship at University Hospital in Boston, a National Institutes of Health Nutrition and Metabolism Research fellowship at Harvard Medical School, and a Gastroenterology fellowship at The Mt.Sinai Hospital in New York. He is board certified in Internal Medicine, Gastroenterology, and Nutrition.
Dr. Klein is past-president of the North American Association for the Study of Obesity and the American Society for Clinical Nutrition. He was elected to the American Society for Clinical Investigation in 1996 and to the American Association of Physicians in 2008. Dr. Klein has had consistent R01 funding from the NIH since 1990, and has published more than 350 papers in nutrition, metabolism, and obesity. Dr. Klein's research activities are focused on understanding the mechanisms responsible for metabolic dysfunction associated with weight gain and obesity, and the pathophysiology of nonalcoholic fatty liver disease.