Insights on Obesity Research from Samuel Klein, MD

Dr. Samuel Klein, MD, recently honored as the recipient of the Endocrine Society’s 2026 Outstanding Clinical Investigator Laureate Award, has dedicated over 30 years to studying the diverse effects of obesity on individuals. This interview with Endocrine News sheds light on his research and the pressing questions surrounding obesity and metabolic health.

For more than three decades, Dr. Klein has been investigating a fundamental query: why do some individuals with obesity experience severe metabolic disorders while others seem to remain unaffected? His research, grounded in extensive human studies and translational science, has greatly enriched the understanding of fat biology and the associated metabolic risks. Recognized for his substantial contributions, Dr. Klein will be presented with the Laureate Award at ENDO 2026, taking place in Chicago from June 13 to June 16.

In his current role at Washington University School of Medicine in St. Louis, Dr. Klein serves as the William H. Danforth Professor of Medicine and Nutritional Science. He also directs the Center for Human Nutrition alongside the Division of Nutritional Science & Obesity Medicine. His academic journey began with a medical degree from Temple University, followed by a master’s in nutritional biochemistry and metabolism from the Massachusetts Institute of Technology. Klein further honed his expertise with a fellowship in gastroenterology at Mount Sinai Hospital in New York before joining Washington University’s faculty in 1994.

Throughout his career, Dr. Klein's research has been pivotal in deciphering how weight loss can ameliorate obesity-related metabolic conditions. Rexford S. Ahima, MD, PhD, the director of the Division of Endocrinology, Diabetes, and Metabolism at Johns Hopkins University School of Medicine, highlighted Klein's unique position as a physician-scientist, emphasizing his commitment to human studies aimed at grasping the complexities of obesity and diabetes.

In the interview, Dr. Klein expressed what the Laureate recognition means to him, saying it stands as a tribute to the efforts of research staff, trainees, and colleagues whose contributions have been integral to his work. He underscored the value of integrating clinical and basic science methodologies to delve into the biology of multi-organ systems, which is crucial for advancing understanding of obesity-related metabolic diseases.

Dr. Klein's perspective on the impact of his work over both short and long-term timelines encompasses the various metabolic disorders linked to obesity, such as insulin resistance, prediabetes, type 2 diabetes, and dyslipidemia, as well as their implications for cardiovascular health. He noted the significant variability in how people with obesity exhibit these metabolic complications. Some individuals, he pointed out, remarkably retain metabolic health despite higher body fat.

The conversation steered towards the importance of embracing a flexible research mindset. Dr. Klein cautioned against becoming overly attached to specific hypotheses, advocating for a data-driven approach. He asserted, "Research is an exploration to find the truth. There is nothing wrong in being wrong; however, it is a mistake to cling to unsupported positions."

Dr. Klein hopes that his studies will encourage further exploration of the metabolic heterogeneity spectrum by examining both metabolically healthy and unhealthy individuals with obesity. He believes that uncovering the underlying mechanisms at both ends of this spectrum can illuminate potential strategies for mitigating obesity-related metabolic diseases and uncover new therapeutic pathways.

When asked for advice aimed at early-career scientists, he reiterated the necessity of adapting to the evolving nature of research. He encouraged others to remain open-minded and responsive to new data.

Reflecting on his career, Dr. Klein mentioned that if he could revisit the early stages of his research journey, he would allocate more time for personal interests and hobbies, which is crucial for a balanced lifestyle and should be considered by those in demanding careers like science.

Outside of his professional duties, Dr. Klein finds respite in exercise and has a particular fondness for reading true crime novels, asserting that these activities allow him to unwind.

The Outstanding Clinical Investigator Award, which Dr. Klein is receiving, has celebrated outstanding contributions to the understanding of endocrine and metabolic diseases since its inception in 1944. Those to be honored, including Dr. Klein, will be recognized during the upcoming ENDO 2026 conference.

In discussing his work, Dr. Klein’s commitment to unveiling the complexities of obesity and its metabolic ramifications stands out. His interdisciplinary approach and dedication to understanding varied responses to obesity not only pave the way for advancements in clinical care but also highlight the nuanced nature of metabolic health. As the conversation wraps up, it is clear that Dr. Klein’s influence in the field of nutritional science and obesity medicine will continue to be felt for years to come.