Lab Members

Dr. Jonathan Krakoff is the section chief of the Obesity and Diabetes Clinical Research Section, Phoenix Epidemiology and Clinical Research Branch and a board-certified endocrinologist and internist. His research investigates the etiology of type 2 diabetes and obesity, primarily by focusing on issues that affect energy balance, energy expenditure, and energy intake.

Dr. Douglas Chang is Medical Director of the Clinical Research Unit in the Obesity and Diabetes Clinical Research Section of NIDDK Phoenix.  Dr. Chang is board certified in both Internal Medicine and Obesity Medicine.  Current research interests include understanding determinants of energy intake and expenditure with a special emphasis on examining the interaction between hydration and obesity which is characterized by prolonged energy imbalance. Additional research examines the role of insulin and glucose regulation in metabolism and investigates novel biomarkers of type 2 diabetes.

Dr. Marci Gluck is Director of Behavioral Sciences in the Obesity and Diabetes Clinical Research section of the NIDDK. She is a trained clinical health psychologist, having completed her graduate training from the Albert Einstein College of Medicine from Yeshiva University, her predoctoral internship at Yale University School of Medicine, and her NIH postdoctoral fellowship at Columbia University College of Physicians and Surgeons. Dr. Gluck has over 20 years of experience conducting clinical studies in adults with obesity and disordered eating behaviors. Her research focuses on the integration of behavioral, neuropsychological and physiological mechanisms that influence appetitive behavior and body weight regulation.  In her spare time, Dr. Gluck enjoys hiking, spending time with her two dogs Ben & Jerry and complaining about the Arizona heat!

Dr. Votruba has a Ph.D. in Nutritional Sciences and is a Registered Dietitian. She is the only R.D./Ph.D. at NIDDK PECRB, and is responsible for the oversight of the metabolic kitchen and also functions as a PI on several studies. Her research interests include improving measurement of food intake and establishing determinants of weight loss and gain. Her broader research interests are in the metabolic determinants of obesity, obesity phenotypes, the measurement of food intake, the development of biomarkers of food intake, and the interaction of the microbiome with the physiology of metabolism.

Tomás Cabeza de Baca, Ph.D., is a staff scientist for the Obesity and Diabetes Clinical Research Section in Phoenix, Arizona. He received his doctoral degree from the University of Arizona and completed his postdoctoral training at the University of California, San Francisco. His research interests include the examination of psychosocial, ecological, and physiological determinants of energy intake and expenditure and their underlying effects on cardiometabolic risk and physiological deterioration. In his spare time, Tommy enjoys shortening his telomeres with cheeseburgers and tequila.

Paolo Piaggi, Ph.D. is interested in the physiological and genetic determinants of the energy balance equation (energy intake and expenditure) and the role these play in contributing to weight change and in predisposing individuals to obesity.

Emma J. Stinson, M.P.H. is a statistician for the Obesity and Diabetes Clinical Research Section in Phoenix, Arizona. She received her master’s degree in Biostatistics from Drexel University in March of 2020. Her research interests include the development and application of statistical methodology in the study of obesity and eating behaviors with an emphasis on the psychosocial and behavioral determinants of energy intake and energy expenditure.

Beyza Aydin, M.D. is a visiting fellow for the Obesity and Diabetes Clinical Research Section in Phoenix, Arizona. She received her M.D. from Istanbul University, Istanbul Faculty of Medicine, Turkey, in 2019. She practiced as a physician in an emergency department in Turkey for 20 months. Beyza's primary project focuses on the effects of seasonality on the measurement of spontaneous physical activity, 24-hour energy expenditure, and substrate oxidation in an indirect calorimetry metabolic chamber. She is also interested in studying t-DCS brain stimulation as a potential mediator of weight loss and its long-term effects on caloric intake.

Cassie holds her Ph.D. in clinical physiology and metabolism from Virginia Tech and is a registered dietitian (R.D.). Cassie completed her supervised clinical hours to become an R.D. through Phoenix Indian Medical Center in 2019, and then joined the ODCRS in May 2019. She has a decade of experience collaborating and conducting research focused on nutrition, exercise and physical activity research in both clinical and community populations. In her spare time she enjoys experiencing nature with her rescue dogs and horses. 

Andres received his medical degree and graduated as a psychiatrist from Universidad Autonoma de Nuevo Leon, in Monterrey, Mexico. His research interests include eating behavior, mental health, emotional regulation, and prevention of obesity and psychiatric disorders. He moved to Phoenix with his wife and they love discovering the city and its surroundings.

Yigit Unlu, M.D. is a visiting fellow for the Obesity and Diabetes Clinical Research Section in Phoenix, Arizona. He received his doctoral degree from Acibadem University School of Medicine in Istanbul, Turkey and practiced medicine in an E.R. for 10 months before joining NIDDK. His research interests include the effects of Gut Hormones on Substrate Oxidation, Energy expenditure, different aspects of diet induced thermogenesis and clinical application of these findings.

Mary has a Master’s of Science in Nutrition and recently completed her dietetic Internship at Phoenix Indian Medical Center. Mary passed her RD exam in March of 2022 and is currently working as a post bac IRTA before applying to a PhD in Nutrition program. Her research interests focus on the relationship between dietary, biological, metabolic, or behavioral differences in individuals with obesity and other chronic conditions. In her free time you will usually find Mary hiking, at Pilates or Yoga, cooking, or reading.

Nicolas is a post-baccalaureate fellow in the Obesity and Diabetes Clinical Research Section. He received a B.S. in Biochemistry in 2016 and a M.S. in Neuroscience in 2021 from Arizona State University and is interested in metabolic, cognitive, and psychological health. His masters research explored mindfulness interventions for adults with autism, as well as relationships between food insecurity and cognitive function. As an IRTA fellow, he is exploring a variety of factors that may contribute to disruptions in food intake and energy metabolism. Outside of research, Nicolas enjoys cycling, being outdoors and roasting coffee. After completing his IRTA fellowship, he will attend medical school.

Meeah is a post bac IRTA working in the Obesity and Diabetes Clinical Research Section. She graduated with her B.S. in Biochemistry from Austin Peay State University in May 2022. Currently, she is working on a project looking at insulin action as a possible predictor of diabetic nephropathy. After completing her fellowship, she plans to attend medical school where her continued focus will be on addressing health disparities that exist in rural and underserved populations. In her free time, she loves to try new food and hike with her husband and two dogs.