Is the Whole Food Plant-Based No Oil Diet Healthy? A Dietitian Explains

Plant-based diets are increasing in popularity, and with good reason! These diets are environmentally friendly and animal-friendly and have been linked to many health benefits. One specific variation on plant-based diets is the Whole Food Plant-Based No Oil diet. 

How healthy is this diet and what do you need to know before adopting it? As a registered dietitian and expert in plant-based nutrition, I’ll answer these questions and more below!

What is the Whole Food Plant-Based No Oil diet?

The Whole Food Plant-Based No Oil (WFPBNO) diet is an eating pattern focused exclusively on plant-based foods in their whole or only slightly processed forms. It encourages eating fats from whole foods, such as avocados, nuts, and olives, rather than oils.

With WFPBNO, you can eat plenty of:

• Whole fruits (including olives)
• Vegetables
• Beans
• Legumes (peas, lentils, etc.)
• Nuts and nut butters
• Seeds
• Whole grains

Also included are plant-based foods which have been slightly processed, but still contain all or most of the healthful components present in their “whole” forms. 

An example of this is tofu. Tofu is made from whole soybeans, which are processed into soy milk. Soy milk is then coagulated into tofu. While tofu is more processed than soybeans, it still contains much of the fiber, protein, vitamins, and minerals found in soybeans, and therefore is usually accepted in WFPBNO.

One variation of this diet is to limit but not completely avoid high-fat plant foods like nuts and nut butters, making the diet low-fat. 

People following WFPBNO avoid the following foods:

• Animal-based foods (eggs, meat, dairy, butter, fish, honey, lard, etc.)
• Fruit-based foods with part of the fruit removed (e.g., juice or applesauce made with peeled apples)
• Refined sugars and sweeteners (e.g., white sugar, brown sugar, artificial sweeteners, candy, most desserts)
• Protein powders
• Vegetable oils (e.g., coconut oil, avocado oil, olive oil) and foods cooked in oil
• Refined grains (e.g., white flour, white rice, white bread, white pasta)

RELATED:Your Guide to Vegan Fats

History of WFPBNO

Dr. T. Colin Campbell, a researcher at Cornell University, first used the term “plant-based”¹ in the early 1980’s to refer to a plants-only style of eating. He later added “whole foods” to emphasize the difference between a plant-based diet based on whole, minimally processed foods rather than relying on supplements or foods which have been more highly processed.

This style of eating was also used by Dr. Caldwell Esselstyn, a physician with the Cleveland Clinic, to treat and reverse coronary artery disease² with his findings published in 1995.

How does WFPBNO differ from other plant-based diets?

The meaning of the term “plant-based” has changed since its introduction by Dr. Campbell in the 1980’s. While previously used to refer to exclusively eating plants, recently its meaning has become more flexible. It’s now often used to describe eating patterns anywhere between plants-only to diets heavy in plants but which may also include small amounts of animal-based foods.

WFPBNO is the only plant-based diet to specifically avoid oils. It has essentially the same meaning as the term “whole food plant-based” (WFPB), just with more specificity in the name.

While similar to a vegan diet in the sense that both avoid all animal products, vegans do not specifically restrict oils or processed foods. Vegans avoid animal products in order to reduce animal suffering and may not be focused on the health benefits of plant-based diets.

In contrast, the primary rationale for the WFPBNO diet is to improve the quality of one’s diet and prevent the development of diet-related chronic diseases.

Sources of fat

How does the WFPBNO diet provide enough fat? Don’t we need oils for that? While oils do provide fat in the diet, some whole-food plant-based sources of fat include:

• Almonds
• Walnuts
• Peanuts
• Pecans
• Cashews
• Pistachios
• Chia seeds
• Flax seeds
• Hemp seeds
• Pumpkin seeds
• Sunflower seeds
• Sesame seeds
• Tahini
• Peanut butter
• Almond butter
• Coconut 
• Avocados
• Olives
• Cacao nibs
• Tofu and edamame (high in protein but also contain some fat)

RELATED: Best Nuts for Vegans

Advantages of WFPBNO

Nutrient density

Since WFPBNO includes whole, minimally processed plant-based foods, you are truly getting the most nutritional bang for your buck. This is the basic idea behind nutrient density, which refers to getting the most nutrients for a certain amount of calories.

Whole plant foods are nutrient-dense because they haven’t had any beneficial nutrients like fiber, vitamins, minerals, and antioxidants removed from them. They also haven’t had any refined sugars or excess fat or sodium added to them. Most whole plant-based foods are naturally low in saturated fat and trans fat.

Because these foods are high in nutrients for the amount of calories present, WFPBNO diets can be helpful for losing excess body fat³.

Heart disease 

WFPBNO can be used to effectively manage heart disease and may help stop its progression or even reverse this condition in some people. Dr. Esselstyn showed that a WFPBNO diet, along with cholesterol-lowering medications, reduced cholesterol levels and halted the progression of heart disease² in a small sample of patients.

In a 2014 update with 198 participants, 93% of patients who adhered to a WFPBNO diet reported improved or non-existent chest pain compared to before they started the diet. 22 patients experienced a reversal of their heart disease, and 27 were able to avoid having surgery. 

Out of all adherent patients, only one stroke occurred as a result of disease progression. 99% of patients following the diet did not experience any major cardiac events such as heart attacks or strokes.

Considering that WFPBNO diets are low in saturated fat and added sugars and high in dietary fiber and antioxidants, their heart-healthy benefits aren’t surprising.

Type 2 diabetes

Plant-based diets like WFPBNO that are rich in whole plant foods can be helpful in managing and preventing type 2 diabetes⁴. 

They’re rich in dietary fiber and low in added sugars, helping to manage large spikes in blood sugar. They’re also helpful in preventing insulin resistance, which over time can progress to type 2 diabetes. Beans and legumes, while often feared for their carbohydrate content, can actually help lower blood sugar levels after meals⁵.

Challenges and disadvantages 

Avoidance of oils

The argument against oils used by WFPBNO proponents is that because oils are processed, they’re basically empty calories. It’s true that processing whole plants, like olives, into oil removes the fiber and some vitamins and minerals. It’s also true that oils are easy to overeat.

However, oils shouldn’t be considered empty calories. Expeller-pressed, cold-pressed, and extra-virgin varieties do contain significant amounts of vitamins and antioxidants. Extra-virgin olive oil, for example, is a great source of fat-soluble vitamins E and K.  

Another argument used against oils is that they harm the cardiovascular system by reducing flow-mediated dilation, a measure of how well the arteries expand and allow blood to flow.

A study⁶ published in 2000 often cited to support this argument gave participants a small meal with 50 grams of either olive or canola oil with bread and found that those who ate olive oil (but not canola oil) had reduced (worsened) flow-mediated dilation in their arteries. 

There are a few reasons why I don’t believe this study can be used to justify the elimination of all oils:

1. 50 grams of oil is equivalent to about 4 tablespoons – much more than most people would eat at one time! It’s also more than you would get in one serving of, for example, a soup recipe making multiple servings that only uses a half tablespoon of oil to saute vegetables. Because of this, the amount of oil eaten by the participants doesn’t reflect the amount of oil in a real-life meal.

2. In their conclusions, the authors of this study actually mention canola oil as one of the antioxidant-rich foods that give the Mediterranean diet its benefits for artery function.

3. This study only had 10 participants, which is quite low. This means we can’t be confident that we would see the same results in a larger group of participants.

4. When adding balsamic vinegar (in the form of salad with dressing) to the olive oil and bread, flow mediated dilation was improved compared to eating the olive oil and bread alone. The study authors suggested that having a mixed meal including acidic ingredients like vinegar or vitamins E and C from fruits and vegetables could reduce any impairments in flow-mediated dilation that might occur with olive oil alone. These types of mixed meals are inherently common in plant-based diets.

5. Short, temporary reductions in flow-mediated dilation may not automatically translate to an increased risk for atherosclerosis. Lifting weights⁷ has been shown to temporarily reduce flow-mediated dilation after exercise, but is well-known for its musculoskeletal and other health benefits. We wouldn’t tell people to avoid lifting weights, so avoiding oil for this reason is likely unwarranted. We see benefits in flow-mediated dilation with Mediterranean diets that include olive oil compared to low fat diets, indicating that a moderate amount of oil in a predominately whole food plant-based eating pattern likely isn’t the dietary villain it’s sometimes made out to be. The amount of fat in the diet appears to have less of an effect on cardiovascular function than does the type of fat⁹ – namely, unsaturated fats are better for the cardiovascular system than saturated and trans fats. Whole food plant-based diets are naturally low in saturated and trans fats, making them beneficial for heart health regardless of whether they include oils or not.

Additionally, some people struggle to get enough calories with WFPBNO since it’s so rich in satiating dietary fiber. Strictly avoiding oils or following a low fat version of WFPBNO where even whole plants high in fat (like nuts and avocados) are limited may make it challenging for these people to keep enough weight on.

RELATED:Is Olive Oil Vegan? (Why Some Vegans Avoid It)

May be difficult to follow

WFPBNO may be challenging for people who don’t know how to cook or who have limited time or space for cooking. While there are some brands of frozen meals and convenience foods that are WFPBNO-friendly, this diet usually requires some level of cooking and food preparation. 

Strategies like batch-cooking, purchasing pre-chopped fruits and vegetables, stocking canned beans, and keeping microwaveable bags of rice or other grains in the freezer can help with overcoming some of these challenges.

It may also be challenging to find restaurants with WFPBNO-friendly menu items or who have the ability or willingness to modify their dishes. These restaurants may be few and far between, especially in smaller towns or rural areas that have limited options. This can make the social aspect of going out to eat with friends and family less enjoyable.

May cause gastrointestinal discomfort

Because the WFPBNO diet is composed entirely of minimally processed plant foods, it’s quite high in fiber. Its fiber content provides many health benefits, but can cause uncomfortable levels of gas and bloating, especially when switching immediately from a low fiber diet to WFPBNO.

To prevent or ease these unpleasant symptoms, be careful to increase your fiber intake gradually and drink plenty of water throughout the day. Some tips for gradually eating more fiber include:

• Slowly increasing the portion sizes of fruits and vegetables at meals
• Cook most of your vegetables at first rather than eating all of them raw
• Alternate between whole grains and non-whole grains (brown rice at lunch, white pasta at dinner)
• Choose legumes and soy foods that tend to be less gas-producing, like red lentils, tofu, and tempeh
• Drink smoothies and eat blended soups
• Cook dried beans until very tender and easily mashable. You can also soak them overnight, discard the soaking water, and rinse them before cooking.

Vitamin B12

Vitamin B12 is mostly lacking in whole plant-based foods, so people following WFPB will either need to get enough from fortified foods or take a supplement.

Recent Research

Recently, a new study¹⁰ was published that some WFPBNO proponents have taken as proof that oils are dangerous for our health. However, the results aren’t so cut and dry.

This study involved adults at risk for cardiovascular disease who were told to follow either a high olive oil (4 tablespoons per day) WFPB diet or a low olive oil (<1 teaspoon per day) diet for for 4 weeks, after which they switched to the other diet for another 4 weeks.

The authors found a mix of positive and negative outcomes from the high oil diet. When switching from high oil to low oil, LDL cholesterol levels went down (improved). When switching from low oil to high oil, glucose levels and cholesterol levels both increased (got worse). However, the high oil diet led to improvements in HDL, or “good”, cholesterol.

Overall, the study found that both diets reduced LDL cholesterol and improved a variety of cardiometabolic risk factors when compared to the participants’ baseline diets. In other words, all participants were at lower risk for cardiovascular disease with both diets.

The high oil diet wasn’t as beneficial for improving LDL cholesterol levels, but it’s worth noting that this diet was much higher in fat than would typically be recommended. When on the high oil diet, participants were getting a whopping 48% of their calories from fat. 

This is MUCH higher than the Dietary Guidelines for Americans’ recommended range for fat intake, which is 20-35% of total daily calories. Using such a high-fat diet doesn’t really reflect real-life consumption, at least not in terms of the recommendations for a balanced diet.

Based on the results of this study, we can’t conclude that including oil while on a WFPB diet is detrimental to heart health. Limiting it may be helpful for people who really struggle to lower their cholesterol, but even the high-oil diet provided health benefits.

Conclusions

So should you follow a WFPBNO diet? The answer will depend on your motivation for changing your diet, your ability to prepare these foods, and the availability of these foods where you live.

The WFPBNO diet is extremely nutrient-dense, making it a great choice for improving your nutrition and for helping to prevent nutrition-related chronic diseases. That said, it may not be appropriate for individuals who need to gain weight or who struggle with poor appetites. 

While excluding oils to maximize health benefits isn’t supported by the available scientific evidence, you can get enough fats without them by eating foods like nuts, seeds, olives, and avocados.

Learn more about the different types of vegans and plant-based diets by reading The 3 Types of Vegans & The Healthfulness of Their Diets.

References

1. Campbell, T. Colin. History of the Term ‘Whole Food, Plant-Based’. T. Colin Campbell Center for Nutrition Studies website. https://nutritionstudies.org/history-of-the-term-whole-food-plant-based/. Accessed October 24, 2022.
2. Esselstyn CB Jr, Ellis SG, Medendorp SV, Crowe TD. A strategy to arrest and reverse coronary artery disease: a 5-year longitudinal study of a single physician’s practice. J Fam Pract. 1995 Dec;41(6):560-8. PMID: 7500065.
3. Wright N, Wilson L, Smith M, Duncan B, McHugh P. The BROAD study: A randomised controlled trial using a whole food plant-based diet in the community for obesity, ischaemic heart disease or diabetes. Nutr Diabetes. 2017 Mar 20;7(3):e256. doi: 10.1038/nutd.2017.3. PMID: 28319109; PMCID: PMC5380896.
4. McMacken M, Shah S. A plant-based diet for the prevention and treatment of type 2 diabetes. J Geriatr Cardiol. 2017 May;14(5):342-354. doi: 10.11909/j.issn.1671-5411.2017.05.009. PMID: 28630614; PMCID: PMC5466941.
5. Melina V, Craig W, Levin S. Position of the Academy of Nutrition and Dietetics: Vegetarian Diets. J Acad Nutr Diet. 2016 Dec;116(12):1970-1980. doi: 10.1016/j.jand.2016.09.025. PMID: 27886704.
6. Vogel RA, Corretti MC, Plotnick GD. The postprandial effect of components of the Mediterranean diet on endothelial function. J Am Coll Cardiol. 2000 Nov 1;36(5):1455-60. doi: 10.1016/s0735-1097(00)00896-2. PMID: 11079642.
7. de Oliveira GV, Mendes Cordeiro E, Volino-Souza M, Rezende C, Conte-Junior CA, Silveira Alvares T. Flow-Mediated Dilation in Healthy Young Individuals Is Impaired after a Single Resistance Exercise Session. Int J Environ Res Public Health. 2020 Jul 18;17(14):5194. doi: 10.3390/ijerph17145194. PMID: 32708408; PMCID: PMC7400374.
8. Yubero-Serrano EM, Fernandez-Gandara C, Garcia-Rios A, Rangel-Zuñiga OA, Gutierrez-Mariscal FM, Torres-Peña JD, Marin C, Lopez-Moreno J, Castaño JP, Delgado-Lista J, Ordovas JM, Perez-Martinez P, Lopez-Miranda J. Mediterranean diet and endothelial function in patients with coronary heart disease: An analysis of the CORDIOPREV randomized controlled trial. PLoS Med. 2020 Sep 9;17(9):e1003282. doi: 10.1371/journal.pmed.1003282. PMID: 32903262; PMCID: PMC7480872.
9. Hall WL. Dietary saturated and unsaturated fats as determinants of blood pressure and vascular function. Nutr Res Rev. 2009 Jun;22(1):18-38. doi: 10.1017/S095442240925846X. Epub 2009 Feb 26. PMID: 19243668.
10. Krenek AM, Mathews A, Guo J, et al. Recipe for Heart Health: A Randomized Crossover Trial on Cardiometabolic Effects of Extra Virgin Olive Oil Within a Whole-Food Plant-Based Vegan Diet. J Am Heart Assoc. 2024;13(15):e035034. doi:10.1161/JAHA.124.035034