Duke Diet & Fitness Center Providers and Staff

Our staff members are specialists in the treatment of obesity and related medical problems including diabetes, cardiovascular disease and other weight-related medical conditions. We also provide additional support through working with DFC staff at home.

Providers & Staff

Medical Staff

Ronald S Sha, MD, PhD – Medical Director, Interim Program Director

Susanne Jackson, BSN, MSN

Nutrition Staff

Elisabetta Politi, RD, MPH, LDN, CDE — Nutrition Director

Christine B. Tenekjian, MPH, RD, LDN – Clinical Dietitian

Fitness Staff

Brian Housle, MEd, MS- Fitness Director/ Exercise Physiologist

Steven G. Risi, BS- Exercise Specialist

Behavioral Health Staff

Sofia Rydin-Gray, PhD - Director of Behavioral Health, Assistant Professor in Psychiatry and Behavioral Sciences at Duke University Medical Center

Kathy Murray, LCSW – Psychotherapist and Integrative Health Coach

Linda Duda, MSW, PCC, CPCC - Integrative Health Coach

Administrative Staff

Dina Lumia - Client Relations and Admissions Manager

Bobby Cale - Business Office Manager/Financial Analyst

Amy D'Unger - Admissions Specialist

Mike Hall - Courier

Roger Vandergrift - Night Manager



Bobby CaleBobby Cale – Business Office Manager/Financial Analyst

Bobby joined Duke Medicine in 1991 at Duke South as a Patient Accounts Representative. He transferred to the Diet & Fitness Center a year later to join the admissions team. He now manages the accounting and business office operations with other responsibilities in admissions, facility management and client services.

Prior to coming to Duke, Bobby was Director of Admissions for Rutledge Junior College and an assistant football coach at his alma mater, the University of North Carolina where he earned a Bachelor’s Degree in Business Administration and also lettered there in football.

Bobby’s interests include golf, contemporary jazz music and sports of all kinds.

DudaLinda Duda, MSW, PCC, CPCC - Integrative Health Coach

Linda Duda joined the DFC Behavioral Health and Health Coaching team in 2014 and is assisting our clients with follow-up support for ongoing success with weight loss and lifestyle changes at home. Linda received her foundation and certification coach training from Coach Training Institute (CTI) and has been credentialed as a Professional Certified Coach (PCC) by the International Coach Federation. In addition, she received her integrative health coach certification from Duke IM. In 1992, Linda completed Reiki training in the Usui Method and has completed the Master Level training. Reiki remains a part of her daily life. Linda has completed the Mindfulness Based Stress Reduction training. Linda has taught in the Duke Integrative Health Coach Professional Training foundation and certification programs since 2008 as an instructor, coach and supervisor. She is also interested in the impact of somatic learning and has completed a Somatic Teacher Education Course in May 2013 at the Body Therapy Institute.

Linda has also worked on a variety of research studies focused on specific health conditions, such as Type II Diabetes, Cardiovascular Disease and Tinnitus, genetic screening/life style change for individuals with Cardiovascular Disease and Type II Diabetes predispositions.

Raising the client’s level of awareness and mindfulness remains an essential and integral part of her coaching strategy. Linda knows the values in the magnificent healing power that is present when mind and body work together. She remains committed to using her skills to help our clients who are interested in implementing and sustaining a healthy lifestyle.

D'UngerAmy D'Unger - Admissions Specialist

Amy is a Durham native who graduated from Furman University with a B.A. in Sociology. After serving in an AmeriCorps VISTA role in Washington state, she made her way back to Durham.

Amy began working at the DFC in December 2012 as a temporary staff member and instantly realized what a life-changing program the DFC was. As the administrative specialist, she is now the first person many people speak or email with before arriving to the program and loves helping people realize the difference the DFC can make in their lives.

Mike HallMike Hall – Courier

Mike Hall is a Durham native, and is currently the designated courier at the DFC, providing transportation for clients to and from their appointments as well as performing other administrative duties at the center. Mike is known for his warm welcoming of all new clients at the beginning of their DFC experience.



Brian Housle, MS, MEDBrian Housle, MEd, MS - Senior Exercise Physiologist

Brian has been a member of the Duke Diet & Fitness Center since August 2001. He holds a Master’s in Health Psychology from Penn State and a second Master’s in Exercise Science from East Stroudsburg University. Brian began his career as a teacher and coach at the high school level and college levels. All through his 15 year teaching career, he has worked as a personal trainer, exercise physiologist and health educator, and he brings experience with populations ranging from youth to the elderly, and from college athletes to the everyday person.

Brian currently is a Stott certified Pilates instructor, and specializes in Kickboxing and Aquatics. Brian holds certification from the American College of Sports Medicine as a Health Fitness Specialist and is a Wellness Coach through the same organization. For many years, he served as a Wellness Coach at the DFC and continues to work with several clients in a coaching capacity.

Brian has been a presenter at many national and regional conferences, including The Obesity Society and the American College of Sports Medicine.

Suzanne Jackson, BSN, MSNSusanne Jackson, BSN, MSN

Susanne is originally from New England, fleeing the long and cold winters in 1991. She attended St. Anselm College in Manchester, NH where she obtained a BSN and worked for more than 20 years as a clinical nurse, educator, and nurse manager.

After moving to North Carolina, Susanne went to Duke University where she earned an MSN and became a Family Nurse Practitioner in 1998. Since then, she has been working as a Nurse Practitioner in the Duke outpatient clinics and the Diet & Fitness Center. Susanne loves her job, patients, and colleagues.

The words she lives by are about hope, which she believes we all must have to accomplish anything.

LumiaDina Lumia - Client Relations and Admissions Manager

Dina is originally from Long Island, New York, where she obtained a Master’s Degree in Healthcare Administration at Hofstra University. Dina enjoyed working and living in New York City where she held various positions at Beth Israel Medical Center and Mt. Sinai Medical Center. Shortly after to moving to Raleigh, North Carolina, in 2001, Dina was hired as the Client Relations Specialist at the Duke Diet & Fitness Center. She manages the DFC admissions office.

Dina’s communication skills and experience working directly with patients have proved valuable in her position at the DFC. Dina is responsible for ensuring client satisfaction through coordination of services provided by medical, nutrition, fitness and health psychology. Dina enjoys working in an environment that fosters healthy living and utilizes strategies that transform people’s lives.


Kathy has been a member of the Behavioral Health staff at the DFC since 2002. She enjoys facilitating behavior change through mind/body approaches such as mindfulness and acceptance therapies, guided imagery, and Positive Psychology. She has expertise in assisting clients going through crisis and life transitions, career changes, and relationship issues. She has a special interest in helping people explore their deeper needs and values to enable them to create a healthy lifestyle. Kathy’s prior experience was at the Duke Addictions Program working with individuals and families who struggle with alcoholism and addiction.

Kathy is a Licensed Clinical Social Worker and holds a Masters’ Degree in Social Work from New York University. She has completed the Mindfulness-Based Stress Reduction Program for Professionals, and the Integrative Health Coaching Program at Duke Integrative Medicine. Her work is also informed by training in Non-Violent Communication, Positive Psychology, Focusing and EMDR.

PollittiElisabetta Politi, RD, MPH, LDN, CDE — Nutrition Director

Elisabetta brings more than 20 years of experience as a registered dietitian to her work at the DFC.

Originally from Northern Italy, Elisabetta moved to the United States in 1989. Her professional career has been dedicated to the prevention of chronic diseases through diet and weight management.

At the Diet & Fitness Center, Elisabetta oversees the nutrition and food service programs, including assessment, treatment, and education. She is also a certified diabetes educator, and works closely with diabetic patients.

Elisabetta holds a B.S. in Food Science and Technology from the University of Milan, and a Master in Public Health Nutrition from the University of North Carolina at Chapel Hill.

RisiSteven G. Risi, BS – Exercise Specialist

Steven has been part of the DFC Treatment team since May 2012. He is currently certified by the American College of Sports Medicine (ACSM) as a Certified Personal Trainer. He graduated from East Carolina University which is endorsed by the National Strength and Conditioning Association (NSCA).

Steven's fitness and wellness focus is centered around implementing realistic fun programs that work for each and every individual. His fitness interests include body weight exercise, travel routines, and non-traditional exercise programs of all abilities. His primary goal is to be sure everyone knows their own current abilities, working around (and even overcome) barriers. He stresses that everyone's current ability is much higher than they think.

Sofia Rydin-GraySofia Rydin-Gray, PhD - Director of BEHAVIORAL Health, Assistant Professor in Psychiatry and Behavioral Sciences at Duke University Medical Center

Dr. Rydin-Gray applies a Cognitive Behavioral Therapy approach to treating a variety of conditions that interfere with quality of life. She specializes in delivering brief clinical interventions with a focus on practical application and skills building. Dr Rydin-Gray’s clinical expertise is in assessing and treating the behavioral components of weight management, binge eating, emotional eating, and other lifestyle related conditions. Her research has focused on understanding the immediate and distal triggers of binge eating, food cravings, as well as behavioral weight loss interventions. She received her PhD in Clinical Psychology from Bowling Green State University in 2007 and she is a Licensed Psychologist and certified as a Health Services Provider in North Carolina.

Ronald S Sha, MD, PhDRonald S. Sha, MD, PhD – Medical Director, Interim Program Director

Dr. Sha serves as the Medical Director and Interim Program Director of the Duke Diet and Fitness Center. He earned both his M.D. and his Ph.D. (molecular biology) degrees from the University of Minnesota.

Following a long career in private medical practice, Dr. Sha joined the DFC staff in 2002. He previously served as Chief of Family Practice for The Carolina Permanente Medical Group. In addition to having extensive experience in the prevention and management of chronic diseases, a major interest of his is the treatment of metabolic syndrome and of diabetes. Dr. Sha especially enjoys his participation in the medical lecture series offered at the Diet & Fitness Center, and in contributing to the DFC research program.

Christine B Tenekjian, MPH, RD, LDNChristine B. Tenekjian, MPH, RD, LDN – Clinical Dietitian

Christine received her undergraduate degree in Biology at the University of Virginia and completed her Master of Public Health and Dietetic Internship at UNC Chapel Hill. She holds a Certificate of Training in Adult Weight Management from the Academy of Nutrition and Dietetics and is a Certified Personal Trainer with the National Academy of Sports Medicine. She has been on the Diet and Fitness Center treatment team since 2007.

Christine became a dietitian because she wanted to help people learn how to eat for a healthy and energized life. She works with clients for weight management, lipid modification, blood sugar and diabetes control, gastrointestinal issues, sports nutrition, sustainable eating, and general wellness. She loves to empower and educate individuals and groups to create practical solutions for better eating in the context of their busy lives.

Outside of work Christine enjoys hiking, jogging, bicycling, camping, yoga, reading, and singing. Her mantra: Enjoy what you want, in moderation and mindfulness, and always consider the resources it cost to get the food to your plate.

Roger VandergriftRoger Vandergrift – Night Manager

Roger came to the DFC in 1999 after a career as a police officer and assistant fire marshall. He now works as the night manager of the DFC building.




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