Dr. Samuel Klein is a distinguished leader in nutritional science and obesity medicine whose pioneering work has reshaped understanding of metabolic disorders worldwide. He currently serves as the William H. Danforth Professor of Medicine and Nutritional Science at Washington University School of Medicine in St. Louis, holding multiple leadership positions including Director of the Center for Human Nutrition and Chief of the Division of Nutritional Science & Obesity Medicine. Dr. Klein earned his medical degree from Temple University in 1979 followed by a master's degree in nutritional biochemistry and metabolism from the Massachusetts Institute of Technology in 1984, completing comprehensive clinical training with residencies and fellowships at University Hospital in Boston and The Mount Sinai Hospital in New York. Since joining the Washington University faculty in 1994, he has established himself as a preeminent authority on obesity-related metabolic disorders through rigorous scientific investigation and clinical innovation.
Dr. Klein's groundbreaking research has fundamentally advanced the understanding of how obesity contributes to metabolic diseases through meticulous investigation of cellular, regional, and whole-body substrate metabolism in human subjects. His laboratory pioneered the use of stable isotope tracers and cellular analysis techniques to elucidate the pathophysiological mechanisms linking obesity to insulin resistance and fatty liver disease, transforming scientific understanding of normal fat physiology and its alterations in metabolic disorders. He conducted the first randomized controlled trial evaluating the effectiveness of the low-carbohydrate Atkins diet for obesity treatment, demonstrating its superior short-term weight loss outcomes compared to conventional dietary approaches, and his research on abdominal liposuction revealed that fat removal alone does not improve insulin sensitivity or reduce cardiovascular risk factors. With over 350 publications to his name and consistent NIH R01 funding since 1990, Dr. Klein's work has established critical paradigms for understanding how weight loss ameliorates obesity-related metabolic abnormalities and improves physical function in elderly populations.
Beyond his research contributions, Dr. Klein has profoundly influenced the field through leadership roles including past presidency of the North American Association for the Study of Obesity and the American Society for Clinical Nutrition, and his election to the American Society for Clinical Investigation in 1996 and the American Association of Physicians in 2008. As Director of the Nutrition Obesity Research Center and Medical Director of the Weight Management Program, he has created vital infrastructure for obesity research and clinical care, training numerous investigators who have established successful research programs in metabolic medicine. Dr. Klein continues to advance the field through innovative studies on the pathophysiology of nonalcoholic fatty liver disease and the mechanisms by which weight loss improves metabolic health, with his current work focusing on optimizing therapeutic approaches to combat the global obesity epidemic. His ongoing research promises to further elucidate the complex relationship between adipose tissue metabolism and systemic health, potentially informing new strategies for preventing and treating obesity-related comorbidities worldwide.
