Our Team

David L. Katz, MD, MPH


David L. Katz, MD, MPH, FACPM, FACP, FACLM is a specialist in Preventive Medicine and Lifestyle Medicine, with particular expertise in nutrition.

He earned his BA at Dartmouth College (1984); his MD at the Albert Einstein College of Medicine (1988); and his MPH from the Yale University School of Public Health (1993).  He completed sequential residency training and board certification in Internal Medicine (1991) and Preventive Medicine/Public Health (1993). 

Katz is the founder and former director of Yale University’s Yale-Griffin Prevention Research Center (1998-2019); Past President of the American College of Lifestyle Medicine; President and Founder of the non-profit True Health Initiative; and Founder and CEO of Diet ID, Inc. He is a Fellow of the American College of Preventive Medicine; the American College of Physicians; the American College of Lifestyle Medicine; and Morse College, Yale University. 

The recipient of numerous awards for teaching, writing, and contributions to public health, Katz was a 2019 James Beard Foundation Award nominee in health journalism, has been a widely supported nominee for the position of U.S. Surgeon General, and has received three honorary doctorates. His most recent book, How to Eat, co-authored with Mark Bittman, is a 2021 IACP Awards finalist.

For more about Founder, David L. Katz, MD, MPH visit

Meet the THI Council Members

The council members of the True Health Initiative share their expertise in areas such as cardiology, environmental health, internal medicine, lifestyle medicine, plant-based nutrition, preventive medicine and more.

Mark Bittman

Mark Bittman has been a leading voice in global food culture and policy for more than three decades. He has written 30 books, including the How to Cook Everything series, Food Matters, and his latest book, Animal, Vegetable, Junk: A History of Food from Sustainable to Suicidal. Mark spent three decades at the New York Times, where he created “The Minimalist,” had a five-year stint as the Sunday Magazine’s lead food writer, and became the country’s first weekly opinion writer at a major publication to concentrate on food.

Mark Bittmsn head shot

Richard Carmona, MD, MPH​

As a physician, police officer, and public health administrator, serving as 17th US Surgeon General, and now Vice-Chairman at Canyon Ranch, Dr. Carmona is an expert in policy systems, preparedness, health disparities and literacy, global repercussions, and direct patient care. His support and guidance of THI programming helps keep us relevant and focused on large picture culture shifts.

Dr. Richar Carmona head shot

Cate Collings, MD, MS, FACC, Dip ABLM

Dr. Collings is Director of Lifestyle Medicine for Silicon Valley Medical Development and El Camino Health Medical Network in the San Francisco Bay Area.  She serves as current President of the American College of Lifestyle Medicine. Dr. Collings has dual board certifications in Cardiology and Lifestyle Medicine. 

Dr. Cate Collings headshot

Beth Patton Comerford, MS

Beth received her undergraduate and graduate degrees in Psychology, with an emphasis on social and organizational psychology. She serves as the Deputy Director of the Yale-Griffin Prevention Research Center where she has directed nutrition and lifestyle research for close to twenty years, Executive Director of Turn the Tide Foundation, and Treasurer for the True Health Initiative.

Beth Comerford

Christopher Gardner, PHD

Consummate research professor at Stanford University has spent 20 years with a focus on plant-based nutrition but has recently expanded his efforts to studying food systems approach to improved diet quality and the link between social movements and improved diet change. Dr. Gardner keeps THI on trend and grounded to our evidence base.

Headshot of Christopher Gardner

John Harris

A retired entrepreneur and philanthropist, John currently serves on multiple for-profit and not-for-profit boards. John is immersed in public service projects in education, health care, wellness, and sport. John has 45 years of experience in the employee health and performance fields. Considered a wellness pioneer, John co-founded Harris HealthTrends, Inc., one of the top five corporate wellness companies in the world, shaping the prevention industry.

John Harris head shot

Danielle Nierenberg

Danielle Nierenberg is President of Food Tank and a leading expert on sustainable agriculture and food issues. Dani has written extensively on gender and population, the spread of factory farming in the developing world and innovations in sustainable agriculture. Danielle has an M.S. in Agriculture, Food, and Environment from the Tufts University Friedman School of Nutrition Science and Policy and spent two years volunteering for the Peace Corps in the Dominican Republic.

Danielle Nierenberg headshot

Tom Rifai, MD, FACP

Dr. Tom Rifai is an expert in Flexitarian and metabolic health and Founder and CEO of FlexMD, a digital health company focused on therapeutic lifestyle support. A diplomate of both the American Boards of Internal and Lifestyle Medicine, he is also a past president of the American Board of Physician Nutrition Specialists. Dr. Rifai serves an important role as THI’s NOTeD Editor.

Dr. Tom Rifai headshot with stethoscope

Walter Willett, MD, DRPH

A renowned author and scientist, Dr. Willett is the former Chair of Nutrition at Harvard T.H. Chan School of Public Health and currently Professor of Epidemiology and Nutrition. His vast publications include more than 1,800 scientific articles on diet and disease and multiple retail books lend an incredible knowledge base to our council, publications and audiences.

Kathleen Zelman, MPH, RDN, LD

Award winning media personality, nutrition communications expert, and consummate professional, Kathleen works with WebMD, is a contributing editor to the Academy of Nutrition and Dietetics Food & Nutrition magazine, James Beard Foundation, and more. Her background in science and nutrition journalism guides THI in our efforts to bring clarity to complex health topics.

Kathleen Zelman

Meet the THI Council Members

The council members of the True Health Initiative share their expertise in areas such as cardiology, environmental health, internal medicine, lifestyle medicine, plant-based nutrition, preventive medicine and more.