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Ornish Diet Review: A Dietitian Explains Benefits and How It Works

By Lauren Panoff, MPH, RD

Published on February 27, 2021

Medically Reviewed by Ana Reisdorf, MS, RD

Dietitian Rating:


About This Rating
The average rating of this product is calculated based on the evaluation of the following factors:
  • Evidence-Based:5.0
  • Easy to Follow:3.0
  • Customization:5.0
  • Sustainability:4.0
  • Safety:5.0
  • Value for the Price:4.0
  • Accountability:5.0

The Ornish Diet is part of the Ornish Reversal Program, a comprehensive lifestyle approach that involves a predominantly plant-based diet. It is backed by decades of high-quality research and is covered by many health insurance companies.

Written by
Lauren Panoff, MPH, RD
Registered Dietitian Nutritionist and Vegan Lifestyle Strategist
Lauren Panoff, MPH, RD is a registered dietitian, freelance writer, speaker, and plant-based (vegan/vegetarian) lifestyle strategist for families. Lauren began her career in dietetics as a clinical dietitian at the University of Michigan Health System.
Medically Reviewed by
Ana Reisdorf, MS, RD
Registered Dietitian Nutritionist
Ana Reisdorf is a registered dietitian nutritionist with 14 years of experience in the field of nutrition and dietetics. She graduated from UCLA in 2002 with a degree in psychology and women’s studies and completed her master’s degree from Central Michigan University in 2010
Ornish Diet Review: A Dietitian Explains Benefits and How It Works


  • Based on abundant scientific evidence over decades
  • Allows for customization based on personal preferences, following basic guidelines
  • Reimbursed by Medicare and many major private health insurance companies
  • Goes beyond diet to include support, exercise, and stress management


  • May feel overwhelming for people not used to eating anywhere near this way
  • Certain aspects could be difficult to sustain, such as the very low fat intake
  • Individual must find a certified provider of this program to enroll, which appear to be limited to facilities in certain states

What Is the Ornish Diet?

The Ornish Reversal Program was created by Dean Ornish, MD, cardiologist and founder of the nonprofit Preventive Medicine Research Institute.

Ornish is an early practitioner of lifestyle medicine, which focuses on whole food eating, regular physical activity, sleep, stress management, and positive socialization to prevent, treat, and reverse disease.

Ornish and colleagues have conducted numerous studies over several decades, demonstrating how diet and lifestyle changes can quickly and effectively benefit health – even saving lives.

Today, his program is officially referred to as Dr. Dean Ornish’s Program for Reversing Heart Disease®.

It’s the first integrative lifestyle medicine program for reversing heart disease and other conditions like early prostate cancer, diabetes, and depression.

Because of its proven success, it’s been reimbursable by Medicare since 2011 under the category “Intensive Cardiac Rehabilitation.” Today, many private medical insurance companies, such as Highmark Inc, Anthem, and HMSA, also reimburse it. (1)

This program encourages you to “eat well, stress less, move more, and love more.” It focuses on four areas of life:

  • What you eat
  • How much physical activity you engage in
  • How you respond to stress
  • How much love and support you have

Ornish Diet’s Scorecard

The Ornish Diet program was objectively evaluated by a dietitian based on the following criteria:

Evidence-Based 5/5
Easy to Follow 3/5
Customization 5/5
Sustainability 4/5
Safety 5/5
Value for the Price 4/5
Accountability 5/5
Overall Rating: 4.4/5

What Food Can You Eat?

The Ornish Diet is based on whole plant foods, encouraging avoidance of highly refined and ultra-processed foods.

The program emphasizes that there are no “good” or “bad” foods. However, it emphasizes eating foods found in their most natural form and does not restrict calories unless weight loss is a primary goal.

Foods encouraged:

  • Fruits
  • Vegetables
  • Whole grains
  • Legumes
  • Soy products
  • Nonfat dairy (no more than 2 servings/day)
  • Egg whites
  • Some good fats that contain omega 3 fatty acids

Foods discouraged:

  • Meat
  • Poultry
  • Fish
  • Added sugars, like maple syrup, agave, honey, white/brown sugar (no more than 2 servings/day)
  • Non-fat sweets (no more than 2 servings/day)
  • Refined carbohydrates (no more than 2 servings/day)
  • Alcohol (no more than 1.5 oz liquor, 4 oz wine, or 12 oz beer/day)
  • Added fats, such as oil, olives, coconut, and avocado

Fat intake is kept at 10% or fewer of calories per day, which will primarily come from fats naturally found in plants, including small amounts of nuts and seeds.

Cholesterol is limited to 10 mg per day, which will most likely come from the restricted dairy allotment.

Sodium is restricted, encouraging herbs, spices, vinegar, and citrus to flavor foods.

Caffeine is limited to reduce stimulants and promote peaceful living.

However, 2 cups/day of green or black tea are allowed for antioxidant benefits. You can have 1 cup of regular or 2 cups of decaf coffee per day.

Recommended supplements include a low-dose multivitamin with minerals that contain vitamin B12 and fish oil (for omega-3 fats).

Supplements should not include iron unless you’re of child-bearing age. Calcium supplements may be recommended under physician guidance.

Evidence to Support Claims

The Ornish Reversal Program has proven its success in reversing heart disease, without drugs or surgery, in a number of randomized controlled trials in the leading peer-reviewed journals.

Some of the research around the effects of these intensive lifestyle modifications on life-threatening disease and health status is discussed below.

Increases Lifespan

A 2008 clinical trial published in Lancet Oncology showed that 3 months of making lifestyle changes significantly increase telomerase, the enzyme involved in lengthening telomeres, which determine lifespan. (2)

Telomere shortening is associated with cellular aging, increased risk for disease, and a shorter life. (3)

No previous studies had examined whether nutritional and lifestyle improvements were associated with changes in telomerase.

A follow-up study published in 2013, among the ten men and 25 external controls with low-risk prostate cancer who agreed to participate, found that lifestyle changes were associated with increased telomere length even 5 years later, compared to controls. (4)

Changes Gene Expression

In a 2008 study published in PNAS, Ornish and colleagues found that over 500 genes are influenced by changes in lifestyle. (5)

More specifically, healthy lifestyle changes were able to turn off disease-promoting genes and turn-on protective genes.

While the study involved men with prostate cancer, the findings were concluded to be likely relevant to everyone.

Reverses Heart Disease

Over 15 publications exist from Ornish and colleagues regarding lifestyle changes in the prevention and reversal of heart disease.

The original research, The Lifestyle Heart Trial, was published in 1990. (6)

The conclusion was that comprehensive lifestyle changes had the potential to reverse even severe heart disease and atherosclerosis after only 1 year, without cholesterol-lowering drugs.

Patients enrolled in the Lifestyle Heart Trial were followed, and their ability to maintain intensive lifestyle changes for 5 years and the effects of doing so were observed. (7)

Those who maintained changes showed significant improvement in disease and overall health compared to controls even in years following.

Plus, participants in the Ornish program have seen significant improvements in biomarkers of heart disease such as total cholesterol, LDL “bad” cholesterol, and triglycerides, as well as a lowering of high blood pressure. (8, 9)

Reverses Diabetes and Prediabetes

The Ornish lifestyle changes have also been proven to benefit diabetes.

People who have made the changes show a statistically significant reduction in HgA1c, and improve glucose control so much that they can often reduce diabetes medication. (10)

Promotes Healthy Weight Loss

Research has also shown that people who follow the Ornish program for 12 weeks had a significant reduction in weight and BMI, losing 20 pounds per year, on average. (11)

Improves Depression Symptoms

Participants of the program who started out with depression and metabolic syndrome were still able to make significant lifestyle improvements, resulting in 73% becoming non-depressed after only 12 weeks of intervention. (12)

Sustainability and Safety

Sustainability depends not only on accountability and personal goals but also on how realistic and cost-effective diet changes are for people.

An interesting area of research demonstrated that this program can be successfully implemented in diverse regions, regardless of sex differences in sociodemographic, medical, psychosocial status. (13)

Furthermore, Ornish and colleagues have shown that their interventions provide substantial cost savings compared to common surgical procedures for heart disease. (14)

Furthermore, a 2011 study on 4,000 patients conducted via Highmark Blue Cross Blue Shield examined program adherence.

They found that overall attendance after 1 year was nearly 88%, with reductions in weight, heart health biomarkers, angina, blood sugar, and depression still significant, and a continued increase in exercise capacity.

While I wonder whether most people are able to stick to the restricted diet once they’re no longer under close medical guidance, I would also assume that the changes experienced are so dramatic that many people have little problem maintaining most of what they’ve adopted.

The program is very low risk, with an added layer of safety and guidance under a physician.

Value for the Price

You can’t really beat the price; not only is it reimbursed by many major health insurance companies, but many participants gain back priceless years of their life.

How It Compares

The Ornish Reversal Program is significantly different from many other diet programs.

While so many diets are focused on weight loss as a primary goal, with health benefits as a secondary benefit, the Ornish Diet essentially does the opposite.

Diet is a major piece of this program, but the combination of other critical aspects of life – activity, support, and stress management – set it apart from most alternatives.

This program does not sell meal kits, supplements, or other material items characteristic of common commercial diets.

Instead, it’s done under medical guidance with the intention of reversing life-threatening diseases and achieving long-term optimal health.

Furthermore, it has undergone numerous studies, from multiple perspectives, something that most diet programs cannot say.

And perhaps the biggest difference is that this program has proven its success so much that it’s covered by many insurance providers.

The Bottom Line

The Ornish Diet has decades of research to back its widespread use and success in reversing life-threatening diseases.

While it could easily be overwhelming at first, with the comprehensive approach, individual-focused medical guidance, and accountability, it has proven successful for thousands of people staring at the end of their life as a result of poorly managed health conditions.

Some aspects of the diet are very restrictive compared to what the average person eats, this seems necessary and efficacious for the population adopting the program for very serious medical reasons.

I would recommend this program to anyone seeking an evidence-based alternative to major surgical or medical interventions to chronic disease.

Even after completing the initial goal, much of the diet could remain sustainable for many people, improving habits for life.

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At WellnessVerge, we only use reputable sources, including peer-reviewed medical journals and well-respected academic institutions.

  1. Decision Memo for Intensive Cardiac Rehabilitation (ICR) Program - Dr. Ornish's Program for Reversing Heart Disease (CAG-00419N):
  2. Increased telomerase activity and comprehensive lifestyle changes: a pilot study:
  3. Telomerase and the benefits of healthy living:
  4. Effect of comprehensive lifestyle changes on telomerase activity and telomere length in men with biopsy-proven low-risk prostate cancer: 5-year follow-up of a descriptive pilot study:
  5. Changes in prostate gene expression in men undergoing an intensive nutrition and lifestyle intervention:
  6. Can lifestyle changes reverse coronary heart disease? The Lifestyle Heart Trial:
  7. Intensive lifestyle changes for reversal of coronary heart disease:
  8. A Very-Low-Fat Vegan Diet Increases Intake of Protective Dietary Factors and Decreases Intake of Pathogenic Dietary Factors:
  9. Effectiveness and Efficacy of an Intensive Cardiac Rehabilitation Program in 24 Sites:
  10. Comparison of Coronary Risk Factors and Quality of Life in Coronary Artery Disease Patients With Versus Without Diabetes Mellitus:
  11. Improvement in Medical Risk Factors and Quality of Life in Women and Men With Coronary Artery Disease in the Multicenter Lifestyle Demonstration Project:
  12. Lifestyle changes are related to reductions in depression in persons with elevated coronary risk factors:
  13. Avoiding revascularization with lifestyle changes: The Multicenter Lifestyle Demonstration Project:
  14. Dean Ornish Program for Reversing Heart Disease Cost Effectiveness Summary: