Robert J. Ostfeld is an American cardiologist and advocate of plant-based nutrition.

Ostfield obtained his MD from Yale School of Medicine and a Masters of Science in Epidemiology from Harvard School of Public Health. He completed his medical internship at Massachusetts General Hospital. Ostfeld is the director of the Cardiac Wellness Program at Montefiore and Professor of Medicine at Albert Einstein College of Medicine. He specializes in cardiovascular disease prevention.

Ostfeld is the committee co-chair of the American Society for Preventive Cardiology's Nutrition Working Group. He co-authored the ASPC's 2022 Clinical Practice Statement on Nutrition and Cardiovascular Disease Prevention. Ostfeld advocates a whole-food plant-based diet to prevent cardiovascular disease and has lectured for the Physicians Committee for Responsible Medicine. He is a council member of True Health Initiative.

Ostfield is a vegan in his personal life and has maintained a plant-based diet since 2010.