Bariatric Surgery

Bariatric Surgery
The mission of The Obesity Society’s Bariatric Surgery Section is to advance the science of bariatric surgery and the clinical management of the bariatric surgery patient utilizing a multidisciplinary approach.


  • Content development and organization of a “Bariatric Day” of Symposia for TOS 2011
  • Obesity Week 2013 Combined Symposia Development—the above stated goal is a preliminary step toward this longer-term project
  • Increased use of electronic resources such as: website bulletin board, list-serv, and links to our department's web-based journal club
  • Continue to build content of our newsletter with relevant information for our membership
  • Develop and distribute information regarding ongoing studies involving bariatric surgery with biannual updates
  • Develop an electronic bariatric surgery journal club



Bariatric Surgery Section Newsletter January 2017

Bariatric Surgery Section Newsletter April 2016


Join the Bariatric Surgery Section

All section members must be a member of The Obesity Society. 

If you are not a member of The Obesity Society, join today.  Be certain to select the Bariatric Surgery Section when completing your profile.

If you are already a member and would like to join the Bariatric Surgery Section please login to your member profile and select the Bariatric Section. Once you have updated your profile, you will receive all communications pertaining to the section.

Please contact Shameeka Green,, Volunteer Manager if you have any questions. 



Samer G. Mattar, MD (Chair, 2016-2017)  

Oregon Health & Science University, Portland, OR

Samer G. Mattar, M.D, is Professor of Surgery, and he is the Chief of Bariatric Services at OHSU. Dr. Mattar's areas of interest include the optimization of outcomes of weight loss surgery, including the improvement, or cure, relevant comorbidities; bariatric surgery in adolescents; the treatment of patients with relapsed weight gain and high-risk bariatric patients. He also has an interest in the laparoscopic treatment of gastroesophageal reflux disease and other diseases of the foregut and the endoscopic diagnosis and treatment of foregut diseases. His areas of research include bariatric surgery outcomes, metabolic pathophysiology and surgical education. Dr. Mattar has held leadership positions at ASMBS and SAGES, and has been a member of TOS since 2003.

Shelby Sullivan, MD (Chair-Elect 2016-2017)   

Washington University School of Medicine, St. Louis, MO

Shelby Sullivan, M.D., is an Assistant Professor of Medicine at Washington University School of Medicine in the Division of Gastroenterology. She graduated with a degree in Nutrition from the University of Wisconsin Madison where she studied the effect of caloric restriction on intracellular insulin signaling in a primate model. She matriculated to Washington University School of Medicine for medical school and stayed through residency and fellowship to continue doing research in obesity and metabolism. Dr. Sullivan’s research focuses on both the pathophysiology of nonalcoholic fatty liver disease in patients with obesity and treating obesity with endoscopic bariatric therapy. Currently, she has a K23 award investigating the effects of an isocaloric diet high in high-fructose corn syrup in patients with obesity and nonalcoholic fatty liver disease using in vivo metabolic techniques including hyperinsulinemic euglycemic clamps and hepatic lipoprotein tracer studies. In addition, she is involved in a number of multi-center industry sponsored trials of endoscopic bariatric therapies for weight loss as either a site primary investigator or sub-investigator. She has been a member of TOS since 2010, and would like to help TOS and the Bariatric Surgery Section members bring endoscopic bariatric therapies into their practices as an option in the management of patients with obesity.

Valentina Ivezaj, PhD (Secretary/Treasurer 2016-2017)  

Yale School of Medicine, New Haven, CT

Dr. Ivezaj is an Associate Research Scientist in the Program for Obesity, Weight, and Eating Research (POWER) in the Department of Psychiatry at Yale University School of Medicine. Dr. Ivezaj’s major and longstanding clinical-research interests focus on psychosocial factors associated with bariatric surgery outcomes. Dr. Ivezaj also has a specific interest in alcohol and substance misuse problems in bariatric surgery patients. Currently, Dr. Ivezaj is playing a central role in several longitudinal studies of bariatric patients. First, she serves as project coordinator for a NIDDK-funded randomized controlled trial testing different behavioral treatments delivered following bariatric surgery aimed at improving eating behaviors and enhancing longer-term outcomes. Second, she serves as co-Investigator on a multi-site (Yale-NYU) study examining bariatric surgery outcomes in an ethnically/racially-diverse patient cohort. Third, she serves as co-Investigator on a multi-site (Yale/Indiana-St. Vincent Hospital) study examining the relationship between weight bias and bariatric surgery outcomes. Fourth, Dr. Ivezaj was recently funded, as PI, to prospectively examine obesity-related functional and psychosocial impairment before and after body contouring surgery among bariatric surgery patients. Finally, Dr. Ivezaj is also involved in collaborative research in community and clinical settings investigating binge eating, food addiction, and obesity in non-surgical populations.

Bec McDorman (Early Career Representative 2015-2017)   

California Polytechnic State University, Pomona, CA

Bec McDorman had Roux-en-Y gastric bypass surgery in 2010 to lose more than 100lbs. She understands the importance of working with professionals to achieve long term weight loss success. She is a dietetic intern at Johns Hopkins Bayview Medical Center in Baltimore, Maryland, while concurrently pursuing her masters in nutrition at Cal Poly Pomona. Her goal is to become a registered dietitian (RD) in order to help pre- and post-op bariatric patients with their journey.

Leslie Heinberg, PhD  (Past Chair, 2016-2017) 

Cleveland Clinic, Cleveland, OH

Leslie Heinberg, PhD, is a Clinical Psychologist, Section Head for Psychology for the Department of Psychiatry and Psychology and Director of Behavioral Services for the Bariatric and Metabolic Institute at the Cleveland Clinic. She is also a Professor of Medicine in the Cleveland Clinic Lerner College of Medicine of Case Western Reserve University. She has been a member of TOS since 2005. Her research and clinical interests include psychosocial aspects of bariatric surgery and weight loss outcomes, eating disorders and disorders of body image.

Susan Z. Yanovski, MD, FTOS (Council Liaison 2016-2017) 

National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD

I serve as Co-Director of the Office of Obesity Research and Senior Scientific Advisor for Clinical Obesity Research at the National Institute of Diabetes and Digestive and Kidney Diseases of the National Institutes of Health in Bethesda, Maryland. I received my medical degree from the University of Pennsylvania in Philadelphia. I completed my residency and fellowship in Family Medicine at the Thomas Jefferson University School of Medicine in Philadelphia and a post-doctoral fellowship in eating disorders research at the National Institute of Mental Health. I have served on the editorial boards of the American Journal of Clinical Nutrition, Archives of Family Medicine, and Eating Behaviors. I have published more than 140 peer-reviewed papers, was a member of the expert panel that developed the 2013 AHA/ACC/TOS Guideline for the Management of Overweight and Obesity in Adults, and have served as Principal Investigator (intramural) and Project Scientist (extramural) on single and multi-site clinical studies. My research interests include behavioral, medical, and surgical approaches for obesity treatment in adults and children and the study of binge eating disorder.