Why No Oil on Plant Based Diet

Oil free diets are becoming more common, especially among members of the vegan community. While some plant-based doctors promote oil free diets to optimize health, is it necessary to remove oil from your diet? As with any nutrition topic, the answer often depends on the individual.

Following a plant-based diet can be challenging enough, so is it worth adding an additional layer of restriction in the form of a no oil diet? This article covers:

1. What are Oil Free Diets?
2. Why do People Follow Oil Free Diets?
3. Research on Oil Free Diet
4. Health Benefits of Oil Free Diets
5. Nutrition Concerns with Oil Free Diets
6. Should you Follow an Oil Free Diet?

What are Oil Free Diets?

Oil free diets are just as they sound: a diet that does not include oil in any form. Someone following an oil free diet would not use any liquid oils, margarine/ butter products or any foods that contain these ingredients.

While anyone could follow an oil free diet, I've personally only seen it popularized as a way of eating among the plant-based/vegan community. Specifically, those who follow a "whole food plant-based" diet approach. Essentially, these people consume only unprocessed plant-based foods. Since oil has been processed, it's off the list of foods that are allowed.

Why do People Follow Oil Free Diets?

From what I can tell, the concept of oil free diets originated among some doctors who promote whole food plant-based diets. The general messages I've seen from the promoters of oil free diets are:

• Processed foods (including oils) aren't meant to be consumed by humans.
• Oil is high in calories and void of nutrition therefore there is no need to consume it.
• High fat diets are harmful to health (specifically heart health); low fat and high carbohydrate diets are typically being promoted instead.
• Oil free diets are a way to "reverse" diseases such as type 2 diabetes and heart disease.

I've even seen the promoters of oil free diets call oil poison/ toxic and that it must be avoided at all costs.

These messages are very clear and powerful. It's extremely easy for someone to hear that a certain food is toxic to humans and then become worried/ fearful about eating it.

One might assume there is a lot of really strong research out there to back up these claims, right?

Research on Oil Free Diets

To be brief, research generally shows the type of fat humans consume is the more important factor in disease risk ¹.

Consumption of unsaturated fats typically shows beneficial health impacts whereas consuming saturated fats is usually associated with negative health impacts ^{1 , 2}. Trans fats almost always show detrimental impacts on human health ^{2 , 3}.

Polyunsaturated fats in particular seem to be the most beneficial for heart health, even when compared to monounsaturated fats ^{1 , 2 , 5}.

The research on oil free diets themselves tends to be quite limited. The research we do have has limitations that are often overlooked, but important in how we interpret the data.

Oil Free Diets and Endothelial Function

Some research suggests consumption of oil harms the endothelium (inner lining of the arteries) and this could be a risk factor for heart disease ⁴.

Two studies are often referenced in relation to oil and endothelial function ^{5 , 6}. Both showed a detrimental effect of oil consumption however one only found the detrimental effect after consuming olive oil, and not after consuming canola oil or salmon ^{5 , 6}.

These studies have limitations. Firstly, only ten young, healthy people were included in each. Secondly, a large amount of oil/ fat was consumed to demonstrate the effect (60 mL of oil in one; about 52 mL of oil/ fat in the other) ^{5 , 6}.

Other research has not found the same effect. The impact of eating a meal high in unsaturated fatty acids may depend on individual metabolic status ⁷.

We need more research into this topic. Studies with a wider variety of people and a smaller amount of fat/ oil (ex 1 tsp or 1 tbsp as opposed to ¼ C) would be helpful in making appropriate conclusions about the effect of oil/ fat on arteries.

As it stands, pointing to these studies and saying "here's proof you should never eat oil" is misleading at best, in my opinion.

Health Benefits of Oil Free Diets

If the research on endothelial function is quite limited, surely there is more convincing evidence for eliminating oil from the diet?

There are a few other studies that point to the benefits of removing oil from the diet for heart health. One that is commonly cited showed people with heart disease (have already had a heart attack) put onto a completely whole food, plant-based diet (including elimination of oil) ⁸. Further cardiac events were found to be extremely low in the people who followed this dietary protocol ⁸.

This is a very interesting study, and while I don't think it should be ignored, when looking at research, it's important to take in a balance of the evidence.

Oil free diets are also said to be good for weight loss. Since oil has a large amount of calories in a small volume, the calories from oil can easily add up without physically filling someone up. While eating larger volumes of food for fewer calories is one approach to weight loss, it's certainly not the only approach.

Additionally, there is a difference between being physically full and feeling satisfied. Fats and oils can make someone feel more satisfied after a meal, and less likely to be seeking food again in a short while.

Nutrition Concerns with Oil Free Diets

It's a good idea consider the benefits of making a dietary change against possible harms of making that change.

With an oil free diet, one must make sure they are meeting their intake requirements for essential fatty acids as well as all fat-soluble vitamins and nutrients. Fats and oils can help nutrient absorption from a meal therefore it's important to include at least some fat in every meal ^{9 , 10}.

If one were to only consume whole food sources of fats from plant-based options, they would essentially be limited to getting their fats from avocados, nuts, seeds and olives. This is a fairly limited range of options, not to mention these whole food fats are expensive (not everyone can afford to eat avocado, nuts and seeds every day).

Oil free diets are almost always promoted within the plant-based community. Given a plant-based or vegan diet is already quite restrictive, adding an additional layer of restriction would be challenging, potentially quite stressful and could lead to concerns with disordered eating behaviours. Becoming so focused on everything you consume can lead down a path of unhealthy food behaviors/ unhealthy relationship to food.

Lastly, it needs to be pointed out that there is a difference between consuming some oil and drowning a meal in oil. While people may not like the word "moderation" it's a good one to remember. Adding 1 tsp or 1 tbsp of oil to a meal is not the same as eating something deep fried or slathered with a large amount of oil (although those types of foods/ meals can be included as part of a healthy diet).

Health Benefits of Fat and Oil Consumption

It's never a good idea to only look at one side of the story. While there is a small amount of research suggesting possible harm with consuming oil, there is also a body of research suggesting a benefit.

The type of fat consumed is really the critical factor in this discussion ^{1 , 2}. Polyunsaturated fats seem to come out on top (as being beneficial for health), followed by unsaturated fats in general ^{1 , 2}. The health benefits also seem to come when saturated fats are replaced with polyunsaturated fats (as opposed to replacing saturated fats with carbohydrates or monounsaturated fats; or simply adding extra polyunsaturated fats to the diet) ^{1 , 2}.

There are many research studies citing dietary patterns that contain oil, even oil in fairly large amounts (ex. the Mediterranean diet which is fairly high in fat including oils) as being beneficial for a number of health conditions ^{11 , 12 , 13 , 14 , 15}. Olive oil and nut consumption are two dietary factors that have been studied, both showing beneficial health impacts ^{16 , 17 , 18}.

Additionally, consumption of unsaturated fatty acids (compared to saturated fats) may help maintain cognitive abilities with age ¹⁹.

Should you Follow an Oil Free Diet?

Firstly, never make changes to your diet without consulting a doctor or dietitian first.

Second, I would caution against following any diet that has a strict focus on elimination of any food/ food group. This is because of the potential harm that restrictive diets may pose especially in terms of disordered eating. Many "healthy" behaviours are actually disordered eating in disguise.

When looking at the landscape of dietary advice out there, you could create yourself quite the list of foods to avoid, depending on who you chose to listen to. How is it that some people promote oil free diets whereas others are promoting ketogenic diets (a diet that is extremely high in fats, including oils)?

People like to live in extremes, especially when it comes to diets. People want to feel part of a group and so find comfort in following (sometimes blindly) a dietary philosophy that they are in alignment with. Moderation, which is practical, reasonable, healthy and sustainable, is often laughed at.

So if you want to avoid oil, and are sure that you can meet your intake requirements for essential fats and fat soluble nutrients, and do it in a way that is not creating disordered eating thoughts/ behaviours, than that's your choice. If you want to consume oils, that's also your choice.

Let's keep in mind that there are benefits to including oil in the diet:

• It makes food taste better
• It helps absorption of fat-soluble nutrients
• Health advantages to inclusion of unsaturated fats
• A more relaxed dietary approach that's more enjoyable

There's nothing wrong with focusing on getting fats from whole food sources, but an all-out elimination may not be warranted and could pose harm.

Life's too short to focus so much on what we eat that we forget to enjoy it.

Summary: Oil Free Diets

Oil free diets are often promoted as an ideal way for humans to eat (along with a complete focus on only eating whole plant-based foods). The research on oil free diets is fairly limited and it's important to look at both sides of the story.

The other side of the oil free story is a body of research that supports inclusion of unsaturated fats (particularly polyunsaturated) from a variety of food sources including oils. Restrictive diets (such as one that eliminates oils and all foods containing this ingredient) can make eating unnecessarily complicated and stressful, and there is potential for development of disordered eating behaviors when one becomes too focused on everything they consume.

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References cited:

1. Effects on coronary heart disease of increasing polyunsaturated fat in place of saturated fat: a systematic review and meta-analysis of randomized controlled trials
2. Intake of saturated and trans unsaturated fatty acids and risk of all cause mortality, cardiovascular disease, and type 2 diabetes: systematic review and meta-analysis of observational studies
3. The toxicity of dietary trans fats
4. The Vascular Endothelium and Human Diseases
5. Postprandial effect of dietary fat quantity and quality on arterial stiffness and wave reflection: a randomised controlled trial
6. Olive, soybean and palm oils intake have a similar acute detrimental effect over the endothelial function in healthy young subjects
7. Acute effects of monounsaturated fatty acids with and without omega-3 fatty acids on vascular reactivity in individuals with type 2 diabetes
8. A way to reverse CAD?
9. Effect of High- versus Low-Fat Meal on Serum 25-Hydroxyvitamin D Levels after a Single Oral Dose of Vitamin D: A Single-Blind, Parallel, Randomized Trial
10. Carotenoid Absorption from Salad and Salsa by Humans Is Enhanced by the Addition of Avocado or Avocado Oil
11. A Mediterranean diet supplemented with extra virgin olive oil or nuts improves endothelial markers involved in blood pressure control in hypertensive women
12. Olive oil intake and risk of cardiovascular disease and mortality in the PREDIMED Study
13. Primary Prevention of Cardiovascular Disease with a Mediterranean Diet Supplemented with Extra-Virgin Olive Oil or Nuts
14. Postprandial Improvement of Endothelial Function by Red Wine and Olive Oil Antioxidants: A Synergistic Effect of Components of the Mediterranean Diet
15. Adherence to the Mediterranean diet is associated with the severity of non-alcoholic fatty liver disease
16. Olive oil intake and CHD in the European Prospective Investigation into Cancer and Nutrition Spanish cohort
17. Olive oil polyphenols decrease blood pressure and improve endothelial function in young women with mild hypertension
18. Crossover study of diets enriched with virgin olive oil, walnuts or almonds. Effects on lipids and other cardiovascular risk markers
19. Dietary Fat Types and 4-Year Cognitive Change in Community-Dwelling Older Women

Please note that this is a curated list of references for the topics above and is not intended to be comprehensive.

Disclaimer: always speak with a doctor before changing your diet. Please read our full website disclaimer.

Author Profile: Nicole Stevens

Nicole is a vegan Registered Dietitian (RD) and founder of Lettuce Veg Out. She provides vegans with balanced meals and easy-to-understand nutrition science.

Having attained a Masters degree and passing a national registration exam, Nicole is a trusted source of nutrition information. She uses this knowledge to educate others about vegan diets and how to thrive as a vegan.

Why No Oil on Plant Based Diet

Source: https://lettucevegout.com/oil-free-diet/

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