Core Faculty

Dr. Diana Thiara is an Assistant Professor of Medicine at UCSF. She is the medical director of the UCSF Weight Management program as well as the Program Director of the UCSF Obesity Medicine Fellowship. Her main scholarly interests are in medical education as well as patient programming for lifestyle change and weight management – she runs a Culinary Medicine program at UCSF and has also created a virtual curriculum for lifestyle change for patients with obesity. She has been interviewed by local and national news organizations to discuss issues in obesity medicine, including KQED, the Wall Street Journal, and the Washington Post. She also lectures nationally to primary care providers about medical and surgical weight loss.

Thiara went to Yale University for her undergraduate education and received her medical degree from Vanderbilt University School of Medicine. She came to UCSF for her Internal Medicine Residency and completed the UCSF Clinician Educator Fellowship. She is a Board Certified in Internal Medicine and is also a Diplomate of the American Board of Obesity Medicine.

Michelle Guy, MD is Professor of Medicine at UCSF. As a clinician-educator she leads faculty development programs to create an inclusive learning environment for students and trainees across all educational settings. She is the Director for Equity and Anti-Racism Continuing Education for the UCSF Differences Matter multi-year initiative. She is also the Director of Diversity for Graduate Medical Education (GME).

Clinically, Dr. Guy is an Internist and Obesity Medicine specialist. She teaches obesity medicine to the first-year medical students at UCSF and lectures nationally on inclusive care of patients with obesity. She is an item writer for the American Board of Obesity Medicine (ABOM) exam and serves on the board for the ABOM.

Dr. Guy has been recognized for her outstanding clinical care by UCSF Health with the PRIDE Exceptional Clinician of the Year Award, by UCSF School of Medicine with induction into the Gold-Headed Cane Society, and her community with the Marin Magazine Top Physician 2015 recognition.

Dr. Guy graduated from the University of Michigan with a B.A. degree in Comparative Literature. She earned her medical degree at the University of Missouri—Columbia and completed a residency in Primary Care at Cambridge Health Alliance—Harvard Medical School. After completing a Chief Residency, she joined the UCSF faculty Division of General Internal Medicine.

Dr. Gina Moreno-John is a Professor of Medicine at UCSF. She is the Director of Diversity, Equity and Inclusion for UCSF’s Division of General of Internal Medicine. She is also the Director of Food Pharmacy Initiatives for UCSF Health. She is the former medical director of the UCSF Weight Management Program. She is a practicing general internist and experienced weight management provider. She lectures about weight loss principles to medical students, residents, and other providers. She is fluent in Spanish.

Dr. Moreno-John completed her undergraduate education at Stanford University and went to Harvard University for Medical School. She completed her Internal Medicine Residency at Massachusetts General Hospital.

Dr. Jonathan Carter is Professor of Surgery at UCSF and Program Director of the Advanced GI Minimally Invasive/Bariatric Surgery Fellowship. He specializes in advanced laparoscopic (minimally invasive) surgery to treat diseases of the gallbladder, bile ducts, esophagus, intestines, stomach, and abdominal wall (hernia).

Carter earned undergraduate and medical degrees at Stanford University. He came to UCSF in 2000 for residency and fellowship training in laparoscopic surgery. At UCSF, he received the Julius R. Krevans Award for Clinical Excellence and the prestigious Fred H. and Esther E. Nusz Achievement Award. He also received the 2008 Haile T. Debas Resident Teaching Award and the 2023 Junior Resident Faculty Teaching Award. 

Dr. Carter is certified by the American Board of Surgery.  He is a fellow of the American College of Surgeons and the American Society for Metabolic and Bariatric Surgery.  He is currently the Chair of the Clinical Issues Committee of the ASMBS.