Fraser is board certified in California in cardiovascular medicine and internal medicine.[3] He is affiliated with Loma Linda University Medical Center and Jerry L. Pettis Memorial Veterans' Hospital and is a distinguished Professor at Loma Linda University School of Medicine.[2][4]
For 32 years he was director of Adventist Health Studies at Loma Linda University.[1] He is currently a lead investigator.[5][6] He contributed to and managed the publications of Adventist Health Study-1 (AHS-1) and guided the development of Adventist Health Study-2 (AHS-2). He received the Distinguished Researcher Award from Loma Linda University.[1]
In 2003, Fraser authored Diet, Life Expectancy, and Chronic Disease: Studies of Seventh-day Adventists and Other Vegetarians which examined the health effects of vegetarian lifestyles including Seventh-day Adventist vegetarians and non-Adventist vegetarians.[7] In 2018, Fraser stated that research from the Adventist Health studies found that Adventist male vegetarians live an average of nine years longer and women six years longer compared to non-vegetarians.[8]
Fraser has authored more than 100 scientific publications in peer-reviewed journals.[3]