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 so 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 is: Even though the AHA-style fat-restricted diet has failed to prevent atherosclerosis, does the ultra-restrictive Ornish-type diet work 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 the more end is the "reversal" program, used to reverse heart disease. A less restrictive version is the "prevention" program. As described above, the Ornish diet is not a singular plan but a spectrum of offerings that range from very low-fat and completely vegetarian to more flexible options that incorporate fish, chicken, avocados, nuts, and seeds.

What You Need to Know

Dr. Ornish has written several how-to books to fully describe his recommendations and 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

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 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—so, whole-wheat bread instead of white, for example.

Legumes, Seeds, and Nuts

Legumes are a good source of protein in a plant-based diet. More nuts and seeds 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

Egg whites are permitted, but not yolks, because of their cholesterol content.

Dairy Products

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, this is not a definitive shopping list, and if following the diet, you may find other foods that work best 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 or eat in any particular way. As long as you eat the approved foods, you can eat as much as you wish. Here is a sample meal plan for three meals and two snacks per day. 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; cornbread
  • Snack: Raw vegetables; hummus
  • Dinner: Green salad with Italian dressing; spinach and mushroom lasagna with whole wheat noodles; roasted asparagus; dark chocolate

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; sweet potato wedges
  • Snack: Pesto dip; vegetables
  • Dinner: Arugula beet salad; mushroom stroganoff; steamed vegetables; chocolate pudding

Day 3

  • Breakfast: Apple spice 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 complaint 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.

While there are many positive aspects of this diet, it is not a cure-all, and it is not perfect for everyone.

Cons

Restrictiveness

Eating a low-fat, vegetarian diet still allows for balanced nutritional intake, as long as special attention is paid to iron and omega-3 fatty acids.

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.

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 USDA recommendations on nutritional balance, with some planning and effort.

Although the USDA MyPlate guidelines include meat, the Ornish diet can meet these recommendations based on its emphasis on fruits, vegetables, and whole grains.

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

Emphasis on Healthy Foods

With the Ornish diet, you will consume plenty of fruits, vegetables, and whole grains. These are healthy foods that many people struggle to get enough of. Whole grains are higher in nutritional content than refined grains and are a healthy choice, supplying fiber, vitamins, and minerals devoid in refined grains.

Low in Unhealthy Fats

There is no room for unhealthy fats on the Ornish diet. Although the diet's fat content is very low (too low for some people), it excludes trans fats and saturated fat. While some saturated fat is acceptable under the federal guidelines, it is recommended to keep it to a minimum.

Health Risks

Hard to Balance Diet

Cutting fat down to 10% of daily intake is challenging for most people. Due to protein limitations, 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.

May Not Work for CAD

There is little doubt that an aggressive lifestyle management program is a useful thing in patients with CAD. But especially given the general failure of low-fat diets to improve cardiac outcomes in other studies, substantial doubt exists about how much benefit the dietary component of this study contributed to the favorable outcomes.

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 CAD 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.

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