The Ornish diet is one, albeit significant, part of the Ornish Program. In simple terms, the Ornish diet is a low-fat vegetarian diet with a focus on eating predominately whole foods while limiting ultra-processed food products.
Fitness, love and support, and stress management are the other tenets of the program. Together, this lifestyle approach claims to make you feel better by increasing energy and quality of life while improving many chronic conditions.
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We asked expert Allison Knott, RDN, CSSD, owner of Anew Well Nutrition, to weigh in on the Ornish diet and the many reported health benefits.
What Is the Ornish Diet?
For almost four decades, Dean Ornish, MD, has been researching the effects that diet and lifestyle changes can have on your health. The Ornish Lifestyle Medicine program reports it can help with weight loss along with reversing heart disease, diabetes and prostate cancer.
The Ornish diet is centered around eating fruits, vegetables, whole grains, legumes, soy products, nonfat dairy and egg whites along with sources of omega-3 fatty acids. On the Ornish diet, these foods should be whole foods that are rich in "good" carbs, healthy fats, lean sources of mostly plant-based proteins and foods rich in protective substances, e.g., vitamins, minerals, antioxidants, etc.
How Does It Work?
The framework of the Ornish diet is based on the Ornish Lifestyle Medicine Dietary Guidelines:
- Eat mostly plants in their natural form
- Limit "bad" carbs (that's the wording from the website, not ours)
- Less than 10 percent of calories from fat
- Eat mostly plant-based proteins
- Moderate sodium intake
The diet also provides recommendations regarding caffeine: Coffee and tea are optional if you are already consuming caffeine and tolerate it well. Limit coffee to one cup per day or up to two cups of black tea a day.
Supplementation support is also included by recommending a low-dose multivitamin and mineral supplement with B12 (without iron, if not of childbearing age), fish oil, and in some cases, calcium.
Other important tenets of the Ornish diet:
- Calories are not restricted (unless you're trying to lose weight)
- Enjoy small frequent meals throughout the day. This is to keep your energy levels stable and to avoid feelings of hunger.
- Keep cholesterol to 10 milligrams or less per day.
- Nonfat dairy foods (no more than two servings per day) and egg whites are allowed.
- Limit added sugars to no more than two servings per day.
- Low-fat foods (veggie burgers, whole-grain crackers, etc.) or nuts should be kept to three servings or less per day.
- Nuts are allowed in smaller amounts; about one-fifth of a typical serving (e.g., five almonds, nine pistachios or two cashews).
- Alcohol is allowed but not encouraged. If alcohol is consumed, limit it to one serving a day.
Proposed Benefits of the Ornish Diet
The Ornish diet has many health and lifestyle benefits:
1. You May Lose Weight
There have been both short- and long-term weight-loss studies conducted on the Ornish diet specifically. An August 2017 study published in Nutrients showed that in all these clinical trials, a modest amount of weight was lost and maintained over six- to 12-month periods.
Other peer-reviewed studies have found that plant-based diets (like the Ornish diet) aid in weight loss. A September 2020 article published in the American Journal of Lifestyle Medicine concluded that whole-food, plant-based diets have greater weight-loss success than other diets that do not restrict calories.
"The Ornish Diet is likely to help you lose weight because it eliminates foods that are naturally higher in calories like high-fat foods and those with added sugar. If it's an enjoyable diet to follow then it may be a good approach for someone looking to lose weight," Knott says.
2. It May Help Reduce Chronic Diseases
There is some controversy and disagreement around the Ornish diet and its health benefits; this mainly applies to its claim to reverse chronic diseases like heart disease and diabetes, and the very low-fat limit the diet requires.
But the research is clear that a plant-based, mostly whole foods diet is effective in lowering the risk of many diseases. The recommended eating pattern from the American Heart Association closely mirrors many of the principles of the Ornish diet, although it's a little less restrictive, allowing lean meats, fish, poultry and some vegetable oils.
3. It's Easy to Follow
Unlike many, many other diets, there's no laborious counting, measuring or tracking involved; just stick to the encouraged foods and servings, and limit others as recommended.
"The Ornish Diet doesn't restrict calories unless you're trying to lose weight. The diet instead emphasizes foods you can eat versus those you eliminate from the diet," Knott says.
No foods are technically off-limits (aside from a few animal products).
4. The Diet Is Planet- and Animal-Friendly
The Ornish diet is predominately plant-based save for some egg whites and nonfat dairy foods. We know plant-based foods are better for animal welfare and they're also safer for Mother Earth, too.
"A significant benefit of the diet is the emphasis placed on eating mostly plants including whole grains, legumes, fruits, vegetables and soy," says Knott. "The diet also discourages highly processed foods that are high in added sugar."
The focus on whole foods and less ultra-processed foods also typically means less cardboard, plastic and aluminum packaging.
Potential Risks of the Ornish Diet
As with many diets, there are some downfalls and potential risks with the Ornish diet:
1. It's Very Low in Fat
One consistent critique from experts of the Ornish diet is the extreme limits put on fat intake including healthy fats.
"The Ornish Diet is a very low-fat diet that recommends no more than 10 percent of total calories from fat. This is not only challenging to meet daily but it's also below the Acceptable Macronutrient Distribution Range of 20 to 35 percent of calories from fat as defined by the Institute of Medicine (IOM). Fat plays an important role in satiety and is essential for the absorption of some nutrients," Knott says.
2. You May Have Nutrient Deficiencies
The Ornish diet is inherently low in vitamins and minerals like vitamin B12, omega-3 fatty acids and potentially calcium. And because of the very low-fat intake, fat-soluble nutrients like vitamins A, D, E and K will not be absorbed as well.
3. It's Hard to Sustain
Given where many of us are starting, moving to a whole food, plant-based way of eating that is also highly restricted in fat, added sugar and alcohol could prove to be a challenge. And because of these significant changes, it may be hard to sustain.
4. It May Be Time-Consuming
Because the diet is centered on whole foods that are minimally processed, this may mean spending more time than we're used to prepping and cooking in the kitchen Many foods we find convenient time-savers may not be part of this diet.
- Weight loss
- Reduce chronic disease
- Easy to follow
- Planet and animal-friendly
- Very low in fat
- Nutrient deficiencies
Foods to Eat
Add these foods to your Ornish diet food list.
Fruits and Vegetables:
- Green beans
Nuts and Seeds:
- Chia seeds
- Pumpkin seeds
- Sunflower seeds
- sesame seeds
- Egg whites
- Nonfat yogurt
Foods to Avoid (or Limit)
Keep these foods off your Ornish foods shopping list.
- Full fat dairy foods (milk, cheese, yogurt)
- Processed sweets and snacks
Ornish Diet: Sample Meal Plan
Intrigued by the Ornish diet but wondering where to start? Try this sample meal plan featuring Ornish diet recipes. Make sure to snack in between meals throughout the day to keep your energy levels stable and your appetite at bay.
- Breakfast: Nutty Chia Breakfast Crunch
- Lunch: Warm Italian Pasta Salad With Charred Broccoli and Bell Peppers
- Dinner: Slow Cooker Chili
- Breakfast: Berry Banana Breakfast Smoothie
- Lunch: Lemony Bulgur Salad with Roasted Carrot Coins and Dill
- Dinner: Vegan Italian Eggplant Parm
- Breakfast: Mediterranean Tofu Protein Scramble
- Lunch: Power Soup Smoothie and Zesty White Bean and Arugula Salad
- Dinner: Cajun Red Beans and Quinoa
The Bottom Line
If you're looking to take your health up a notch but aren't into counting calories or tracking what you eat, you may want to consider the Ornish diet. You'll probably spend more time in the kitchen (and grocery store) at first, but you'll likely feel satisfied (and energized) with all the whole foods options and recipes you'll enjoy.
The diet is extremely low in fat so if you find it hard to follow, or just aren't satisfied, consider bumping up your fat intake from healthy sources like avocados and olive oil.
"Restrictive diets are often difficult to follow long-term which could result in weight regain," Knott says. (In fact, diets that are overly restrictive often land on a list of the worst weight-loss diets.) "I recommend that anyone looking to lose weight find a way of eating that's sustainable and enjoyable over the long term while also providing the essential nutrients required for health," she adds.
- Ornish Lifestyle Medicine
- Nutrients: "Effects of Popular Diets without Specific Calorie Targets on Weight Loss Outcomes: Systematic Review of Findings from Clinical Trials"
- American Journal of Lifestyle Medicine: "A Whole Food Plant-Based Diet Is Effective for Weight Loss: The Evidence"
- American Heart Association: "The American Heart Association Diet and Lifestyle Recommendation"
- Ornish Lifestyle Medicine: "Nutrition"