What Is the Ornish Diet?

Ornish diet

Verywell / Debbie Burkhoff

At Verywell, we believe there is no one-size-fits-all approach to a healthy lifestyle. Successful eating plans need to be individualized and take the whole person into consideration. Prior to starting a new diet plan, consult with your healthcare provider or a registered dietitian, especially if you have an underlying health condition.

The Ornish diet is designed to be a heart-healthy eating plan. It restricts dietary fat quite severely (to less than 10% of daily calories) and requires that fats come from plant sources. In both the medical literature and the popular press, the Ornish diet has been lauded to prevent coronary artery disease progression (CAD) and facilitate an improvement in coronary artery plaques.

All of the books, websites, TV appearances, speeches, editorials, and documentaries that tout the Ornish diet's effectiveness can be traced back to a single clinical trial—the Lifestyle Heart Trial conducted in the 1980s and 1990s by Dean Ornish, MD. However, the idea that low-fat diets, such as those recommended for many years by the U.S. government and the American Heart Association (AHA), effectively prevent atherosclerotic cardiovascular disease has now been generally discredited.

Over the past several decades, clinical studies in which dietary fat was restricted to less than 25% of daily calories have failed to demonstrate a cardiovascular benefit. Eventually, the AHA quietly dropped its low-fat diet recommendation.

The question now is whether the ultra-restrictive Ornish-type diet works in other ways. The 2021 U.S. News and World Report Best Diets ranks the Ornish diet number 9 in Best Diets Overall and gives it an overall score of 3.6/5.

What Experts Say

"The Ornish diet is a very low-fat meal plan designed to promote cardiovascular health. Though there has been some controversy, this diet has proved successful for heart health in several scientific studies. Experts acknowledge it may be difficult for people to adhere to, though."
Chrissy Carroll, RD, MPH

What Can You Eat?

The Ornish diet is a very low-fat, vegetarian eating plan. Actually, it is a spectrum: On one end is the "reversal" program, used to reverse heart disease. A less restrictive version is the "prevention" program. The reversal program is very low-fat and completely vegetarian, while the prevention program is a more flexible option that incorporates animal-based lean protein (such as fish and chicken), along with healthy fats from avocados, nuts, and seeds.

What You Need to Know

Dr. Ornish has written several how-to books to fully describe his recommendations, along with cookbooks to help those on his diet learn a new way to cook. The Ornish diet also encompasses lifestyle changes, including exercise, stress management (through breathing, meditation, and/or yoga), relationships (spending time with, and getting support from, loved ones), and smoking cessation if you are a smoker.

What to Eat
  • Fruits

  • Vegetables

  • Whole grains

  • Legumes, seeds, and nuts

  • Egg whites

What Not to Eat
  • Meat, poultry, and fish

  • Egg yolks

  • Refined carbohydrates

  • Saturated fats

  • Dairy products (in excess)

  • Alcohol and caffeine (in excess)

Fruits and Vegetables

This diet is mostly vegetarian, so prepare for plenty of produce. In addition to those fruits and veggies, you will use vegetarian sources of fats, such as olive oil, for cooking.

Whole Grains

You must swap refined carbohydrates for whole-grain versions on this diet. That means 100% whole-wheat bread instead of white, for example.

Legumes, Seeds, and Nuts

Legumes are a good source of protein in a plant-based diet. Nuts and seeds are higher in fat, so they are available on the prevention plan.

Meat, Poultry, and Fish

On the reversal Ornish diet, no animal proteins are allowed since they contain saturated fats. On the prevention plan, some fish is included, since it is a good source of omega-3 fatty acids.

Eggs and Dairy Products

Egg whites are permitted, but not yolks, because of their cholesterol content. Small amounts of nonfat milk or yogurt are allowed.

Alcohol and Caffeine

Both are permitted, but only in minimal amounts (no more than 2 ounces of alcohol per day; green tea only).

Sample Shopping List

The approved foods on the Ornish diet should be easily available in large grocery stores. If you'd like a lot of variety in your grains, nuts, and seeds, you may want to visit a health food store that has these foods in stock. Keep in mind that this is not a definitive shopping list, and if following the diet, you may find other foods that work better for you.

  • Fruits (apples, berries, oranges, grapes)
  • Vegetables (kale, carrots, potatoes, broccoli)
  • Whole grains (brown rice, oatmeal, whole-grain bread)
  • Grain-like foods (quinoa, buckwheat, barley)
  • Beans and legumes (chickpeas, black beans, kidney beans)
  • Nuts and seeds (walnuts, almonds, cashews)
  • Egg whites
  • Nonfat milk and yogurt
  • Green tea
  • Olive oil

Sample Meal Plan

The Ornish diet does not require you to count calories, eat on a particular schedule, or combine foods in a certain way. As long as you eat the approved foods, you can eat as much as you wish, whenever you wish. Keep in mind that this is not an all-inclusive meal plan and if following the diet, you may find other meals that work best for you.

Day 1

  • Breakfast: Egg white and vegetable frittata; roasted potatoes; strawberries
  • Snack: Nonfat Greek yogurt; peaches; low-fat granola
  • Lunch: Lentil chili; green salad with balsamic vinegar
  • Snack: Raw vegetables; hummus
  • Dinner: Green salad with olive oil and vinegar; spinach and mushroom lasagna made with whole wheat noodles; roasted asparagus

Day 2

  • Breakfast: Egg white vegetable scramble; whole-grain bread; mixed berries; nonfat milk
  • Snack: Green pea guacamole; whole-grain pita bread; grapes
  • Lunch: Tomato soup; black bean veggie burger patty; sweet potato wedges
  • Snack: Pesto dip with vegetables
  • Dinner: Arugula beet salad; mushroom stroganoff; steamed vegetables

Day 3

  • Breakfast: Apple spice oatmeal muffin; nonfat Greek yogurt; blueberries
  • Snack: Green smoothie
  • Lunch: Bean and corn tacos; coleslaw; chipotle sauce; edamame guacamole
  • Snack: Fruit parfait with nonfat yogurt
  • Dinner: Salad with miso dressing; Thai vegetable curry; brown rice; pineapple

Pros and Cons

Pros
  • No associated health risks

  • Satisfies hunger

  • Accessible

Cons
  • Restrictive

  • Hard to sustain

  • Time-consuming

Pros

Safety

There are no special health risks associated with the Ornish diet, as long as basic nutritional needs (for protein, carbohydrates, and nutrients) are met. However, its health claims may not be completely supported by scientific evidence.

Satiety

Although the Ornish diet limits the types of consumed foods, it does not limit the amounts. Eating plenty of fruits, vegetables, and whole grains can usually satisfy hunger.

Accessibility

No specialty foods are required on this diet, and the compliant foods are readily available. Sometimes they can be more expensive (e.g., quinoa pasta vs. traditional versions), but you also save money by cutting out meat. Also, there is no calorie-counting or food-tracking, which may be appealing to some users.

Cons

Restrictiveness

Following a low-fat, vegetarian diet can be challenging, especially for people used to a typical American diet that emphasizes animal-based proteins and higher-fat foods.

Sustainability

With the restriction on fats, refined carbs, alcohol, and caffeine, some people may find it difficult to follow this diet for the long term. It is meant to be a lifelong change, not a temporary one, which is a big adjustment.

Time Commitment

Eating vegetarian can take a lot of prep and cooking time. You also may need to learn how to cook differently, without meat and saturated fats. Also, most convenience foods and meals are off-limits on this diet.

Is the Ornish Diet a Healthy Choice for You?

The Ornish diet shares many characteristics with other low- or no-meat and "heart-healthy" diets. It also generally meets US Department of Agriculture (USDA) recommendations on nutritional balance, with some planning and effort.

Although the USDA MyPlate guidelines include meat as a source of protein, the Ornish diet can meet these recommendations based on its emphasis on plant-based proteins (egg whites and nonfat dairy products also provide protein).

The USDA suggests roughly 2000 calories per day for weight maintenance, although this number can vary significantly based on age, sex, current weight, and activity level. The Ornish diet is based on reducing fat, not calories, so calorie intake will be different for everyone following the diet.

Health Benefits

Although the Ornish diet may not have as large of an effect on cardiovascular health as originally believed, it does introduce some dietary changes that may improve overall health.

Provides Micronutrients and Fiber

With the Ornish diet, you will consume plenty of fruits, vegetables legumes, and whole grains. These are nutritious foods that many people struggle to get enough of. Eating a variety of these foods makes your diet high in fiber and rich in vitamins, minerals, and antioxidants; all of these can play a role in helping support health and prevent chronic diseases.

Limits Sugar and Fat

Although it may not be necessary to completely eliminate saturated fats from the diet, as Ornish suggests, health experts agree that limiting these fats may improve heart health. The American Heart Association recommends consuming no more than 5% to 6% of daily calories from saturated fat (which means about 13 grams a day, if you consume 2,000 calories).

Similarly, consumption of sugar, especially added sugar (vs. the sugars that naturally occur in many foods) is also associated with adverse health outcomes. This diet will reduce followers' sugar intake, which may be beneficial to their health.

Health Risks

Despite its medical pedigree, the Ornish diet may not be appropriate for everyone, and does include some risks. If you plan to make a significant change to your eating patterns, like the one represented by the Ornish diet, discuss it with your health care provider first.

Macronutrient Imbalance

Cutting fat down to 10% of daily intake is challenging for most people. This may lead to a higher carbohydrate intake, which may not benefit someone who has pre-diabetes or diabetes. As well, this minimal fat intake may make it difficult to absorb fat-soluble vitamins.

Micronutrient Deficiency

Plant-based foods contain many valuable micronutrients, but they don't typically offer much calcium, iron, or vitamin B12. Supplements may be required to meet the body's needs for these vitamins and minerals.

A Word From Verywell

Based on the results of the Ornish study—the small randomized trial upon which all the famous claims regarding the Ornish diet are based—the notion that an ultra-low fat vegetarian diet improves heart health should be regarded as an intriguing hypothesis. Still, for weight loss, this diet holds promise and experts say that it is generally safe (although potentially difficult) to follow.

Remember, following a long-term or short-term diet may not be necessary for you and many diets out there simply don’t work, especially long-term. While we do not endorse fad diet trends or unsustainable weight loss methods, we present the facts so you can make an informed decision that works best for your nutritional needs, genetic blueprint, budget, and goals.

If your goal is weight loss, remember that losing weight isn’t necessarily the same as being your healthiest self, and there are many other ways to pursue health. Exercise, sleep, and other lifestyle factors also play a major role in your overall health. The best diet is always the one that is balanced and fits your lifestyle.

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Article Sources
Verywell Fit uses only high-quality sources, including peer-reviewed studies, to support the facts within our articles. Read our editorial process to learn more about how we fact-check and keep our content accurate, reliable, and trustworthy.
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