DeMaria is nationally known for his contributions to bariatric, advanced laparoscopic, and minimally invasive surgery. He is active in many surgical organizations. He is a member of the executive committee of the American College of Surgeons’ Committee on Perioperative Care. He served as Co-Chair of the Bariatric Surgery task force from 2002 to 2004 and Chair of the 2006 Bariatric Surgery postgraduate course for the Society of American Gastrointestinal Endoscopic Surgeons. DeMaria serves as a reviewer for a number of journals including Surgery for Obesity and Related Disorders and JAMA. He is associate editor for clinical surgery for the journal Surgical Innovation. He is the Program Committee Chairman and Co-Chair of the Training Committee for the American Society for Bariatric Surgery. He has co-authored more than 80 original scientific publications in the surgical literature on various topics, co-authored 30 chapters in surgical texts, co-edited 3 books on surgical subjects, and been an invited guest-speaker across the United States.