Limiting or avoiding fat is something we have been hearing for a long time.
Fat consumption has been associated with the increase of heart disease and hypercholesterolemia in the population – thus the idea that one should not consume fat. However, science has revealed over time that the human body is not that simple and fat is truly important for several vital functions.
We know the different types of fat, and we’ve also discovered that some are beneficial to the human body and should be part of our diet, while others ought to be avoided.
In this article, I’ll explain the different types of fat, which ones are essential for your livelihood based on what the most recent scientific evidence shows, and I’ll give you a list of high-fat foods you can include in your diet.
The Different Types of Fat
There are 4 types of fat: trans, saturated, monounsaturated, and polyunsaturated.
The recommended intake of total fat in adults is 20%-35% of the total calories. The minimum of 20% is to ensure adequate consumption of total energy, essential fatty acids, and fat-soluble vitamins, while the maximum of 35% is based on the limitation of saturated fat and the number of calories, which may result in weight gain if exaggerated.
The World Health Organization recommends that the consumption of saturated fat should be less than 10% and the consumption of trans fats less than 1%.
Through the hydrogenation process – as it happens with margarine – the unsaturated fat becomes saturated and part of the hydrogens added to the fatty acids are based on a structure called trans.
The Institute of Medicine has determined that there is no safe level of consumption of industrially trans fats from partially hydrogenated oils.
Trans fats negatively impact several of the risk factors for cardiovascular disease: they increase LDL (“bad cholesterol”), decrease HDL (“good cholesterol”), increase triglycerides, increase inflammation, promote endothelial dysfunction, and can promote hepatic fat synthesis.
For these reasons, it’s recommended that you avoid trans fats as much as possible.
Saturated fat and monounsaturated fat are synthesized in the body for energetic, physiological, and structural functions. Fats rich in saturated fatty acids tend to be more solid at room temperatures, with a few solid examples being butter, margarine, and coconut oil.
The World Health Organization recommends that saturated fat consumption should be less than 10% of the total calories, which is based on a positive correlation between saturated fat intake and LDL concentrations.
Reducing saturated fat promotes the reduction of total cholesterol and LDL cholesterol levels. 2 However, the role of saturated fat in heart disease is more complex. Scientific evidence is not coherent about the correlation between saturated fat consumption and coronary heart disease.
Replacing saturated fat with non-quality carbohydrates such as refined starch or added sugars does not seem to reduce the risk of cardiovascular disease, in fact, refined starch and added sugars appear to be more harmful than saturated fat.
However, replacing saturated fat with high-quality carbohydrates such as whole grains is associated with a lower risk of coronary heart disease.
Reducing the intake of saturated fat and replacing it with polyunsaturated fats appears to reduce (by about 27%) the incidence of cardiovascular disease. There is not much information about replacing saturated fat with monounsaturated fatty acids or protein. 3
Recent studies have revealed that a higher intake of saturated fatty acids is related to a lower risk of stroke as well as lower morbidity and mortality associated with stroke. However, this decrease or increase in the effects of stroke can be related to specific food sources and specific subtypes of saturated fatty acids, so more research is necessary to know if these sources of fatty acids really promote these effects. 4, 5
Omega-9 or oleic acid is the predominant monounsaturated fatty acid. It is considered a healthy fat found in olive oil (approximately 75%), avocado, nuts, and seeds.
To date, there is no scientific literature reporting on harmful effects associated with high consumption of monounsaturated fats and there is not enough data to formulate specific recommendations regarding the consumption of this type of fat.
Polyunsaturated fatty acids include essential fatty acids and have an important role in human health.
The World Health Organization recommends that 0.5-2% of the total energy should be omega-3 fatty acids and 2.5-9% should be omega-6 fatty acids.
Omega-6 fatty acids are very important for various physiological functions, such as stimulating skin and hair growth, regulating metabolism, and maintaining bone health. 8
Linoleic acid is an essential fatty acid. The body cannot synthesize it and therefore must be obtained through food.
Linoleic acid (AL) is derived from other omega-6 fatty acids that can be synthesized in the human body:
- Gamma-linoleic acid (AGL) – can become an essential fatty acid if for some reason there is a decrease in the activity of delta-6-desaturase – an enzyme that converts AL to AGL.
- Dihomo-gamma-linoleic acid – not found in our diet.
- Arachidonic acid
Omega 3 and omega 6 fatty acids produce contrasting effects.
While omega 3 has anti-inflammatory, antiarrhythmic, and antithrombotic properties, omega 6 has pro-arrhythmic and pro-thrombotic properties. 9
Studies have shown that in addition to cardiac protection, omega-3 fatty acids also offer substantial protection against metabolic diseases such as diabetes, obesity, osteoporosis, neurological degeneration, bone fractures, and cancer. 10 Once again, the scientific evidence is variable.
A recent systematic review published in the Cochrane Database of Systematic Reviews concluded that there is high-quality evidence suggesting omega-3s do not have significant positive or negative effects on mortality or cardiovascular episodes and low-quality evidence suggesting that omega-3s may have a mild positive effect on coronary heart disease. 2
Since the effects are very small, the authors concluded that supplemental omega-3 is probably not useful in preventing or treating cardiovascular disease. 2
This study also revealed that there is moderate evidence that an increase in alpha-linolenic acid is likely to reduce the risk of arrhythmia. Alpha-linolenic acid (ALA) is an omega-3 fatty acid considered essential, because like linoleic acid (omega 6), the body cannot produce it and must be obtained from foods.
From ALA our body can produce the other omega 3 fatty acids, namely:
- Eicosapentaenoic acid (EPA);
- Docosahexaenoic acid (DHA).
Some studies support the idea that populations in regions that consume an omega-6/omega-3 ratio close to the 1: 1 ratio have fewer chronic diseases than populations in regions where they consume omega-6/omega-3s at much higher ratios like 15:1.
Why is Omega-3 So Important For Vegans?
EPA and DHA are found in large quantities in fatty fish, as well as in eggs. It is also available in seaweed but in smaller quantities.
Vegans are unable to obtain these fatty acids through their diet and must depend on the transformation of ALA into EPA and DHA. The body converts ALA into EPA and EPA into DHA.
Vegans can obtain ALA through some plant foods like nuts, as well as oils and seeds.
ALA is converted to EPA efficiently, but to produce optimal amounts of DHA, large amounts of ALA may be required. Vegetarians are often advised to increase their consumption of ALA (omega-3) and decrease their consumption of LA (omega-6). This is because the enzymes that convert ALA to EPA and DHA also convert LA to other fatty acids, which means there is “competition” between them.
However, no articles are studying whether or not this approach is healthy and efficient in increasing levels of EPA and DHA, while there is also a minimum of omega-6 required for the proper functioning of our body. 11
The World Health Organization recommends an ALA intake of 2.5-9% of the total calories.
* Although the general recommendation is 1.1 grams for women and 1.6 grams for men, the recommendations tend to be slightly higher in the vegetarian diet. 12
Another viable way to obtain omega-3s is through supplementation.
Sources of Omega-3 Fatty Acids
To achieve the recommended daily doses of ALA for vegetarians, careful daily consumption of one or some of the following foods is necessary:
28 grams of nuts (1/4 cup) provide you with about 2.6 grams of ALA. 12
Nuts are especially rich in polyunsaturated fatty acids, about 76%. 13
These seeds contain more ALA (omega-3) than LA (omega-6).
22 grams of chia seeds (2 tablespoons) contain about 4 grams of ALA and 1.26 grams of LA. 12,13
Therefore, they are a good option to offset other foods in our diet that contain a lot of omega-6 and little to no omega-3.
Linseeds (or Flaxseeds)
The omega-6/omega-3 ratio of flaxseed is even more interesting.
7 grams of ground flaxseed (1 tablespoon) contains about 1.6 grams of ALA and 0.4 grams of LA. 13
Flax seeds are not well digested when eaten whole, so they should always be ground into flour. The ideal is to grind the flax seeds on the spot or store them in the refrigerator for a few days or in the freezer. Since ground flaxseeds expire quickly, you shouldn’t grind large quantities. 12, 13
20 grams of hemp seeds (2 tablespoons) offer about 1.7 grams of ALA, so they are also an option to consider, especially if you want to alternate between sources. 12
7 grams of flaxseed oil (1/2 tablespoon) contain about 3.7 grams of ALA. 12
It is also an excellent option with an omega-6/omega-3 ratio of 1:4.
The oil must be consumed raw and preserved in the refrigerator. 12,13
100 grams of raw purslane contain 300 to 400 mg of ALA.
Purslane is the green leafy vegetable with the highest ALA content and it also offers a little bit of EPA. 100 grams of purslane contains 1 mg of EPA. 14
Other Plant-based Fat Sources
Dried fruits are also referred to as fatty fruits because they’re rich in unsaturated fat but not omega-3.
Almond, hazelnut, cashew, peanut, pecan, macadamia, pistachio are perhaps the most popular.
Avocado has a high-fat content, or more specifically, unsaturated fat.
For every 100 grams, 15 grams are fat, of which 66% is monounsaturated, 12% is polyunsaturated and 14% is saturated.
Seeds are widely recommended in any diet. Besides chia, flaxseed, and hemp seeds, there are other seeds such as sunflower, pumpkin, sesame, and poppy seeds.
Sunflower seeds are rich in polyunsaturated fat, contain omega-6 but do not omega-3.
Sesame seeds are also rich in polyunsaturated and monounsaturated fat, and they contain large amounts of omega-6 but minimal amounts of omega-3.
The aforementioned seeds are healthy, but flaxseeds and hemp are certainly more important due to their high omega-3 content.
Is Coconut Oil Really Healthy?
The coconut oil “trend” grew as a result of news outlets deeming it a very healthy oil.
However, it doesn’t seem to be superior to other oils, namely olive oil, when it comes to the risk of developing cardiovascular diseases. 15
Coconut oil consists of about 92% saturated fatty acids, especially lauric acid and myristic acid. It indeed generates an increase in HDL (“good cholesterol”) but it also produces an increase in LDL (“bad cholesterol”) and total cholesterol. 15,16,18
A systematic review with a 2020 meta-analysis showed that coconut oil significantly increased LDL levels when compared to other vegetable oils, but lowered LDL levels when compared to animal oils. The consumption of coconut oil significantly increased HDL when compared to both vegetable and animal oils. No significant differences were found between oils in triglyceride levels. 18
The use of virgin or extra virgin coconut oil appears to be more beneficial to health than the use of standard coconut oil — possibly because different methods of preparation alter its composition, biological properties, and potential metabolic effects. 18
Coconut oil can be used to cook fries in small quantities, without being reused. It should not be used in submerged fries, in high quantities, due to its low smoke point. 17
Despite the debate and controversy surrounding saturated fat, recommendations for eating this fat remain at 1-10% of total calories. Coconut oil, like other oils, is rich in saturated fat and should not be consumed in excess.
Fat intake in adequate quantities is essential for our health.
However, in a vegan context, what is crucial to remember is that the consumption of omega-3s is especially vital. Contrary to omega 6, vegan sources of omega 3 are limited and their intake is often inadequate. 10
A daily intake of ALA (an essential omega 3 fatty acid) in sufficient quantities is necessary for optimal health.
Vegans can achieve the recommended daily levels by consuming foods like nuts, ground flaxseeds, chia seeds, hemp seeds, and flaxseed oil. Those who do not consume these foods or consume them in less than adequate amounts can opt for an EPA and DHA supplement.
2Abdelhamid AS, Brown TJ, Brainard JS, Biswas P, Thorpe GC, Moore HJ, Deane KHO, Summerbell CD, Worthington HV, Song F, Hooper L. Omega‐3 fatty acids for the primary and secondary prevention of cardiovascular disease. Cochrane Database of Systematic Reviews 2020, Issue 3.
3Hooper L, Martin N, Jimoh OF, Kirk C, Foster E, Abdelhamid AS. Reduction in saturated fat intake for cardiovascular disease. Cochrane Database of Systematic Reviews 2020, Issue 5. Art. No.: CD011737.
5Kang ZQ, Yang Y, Xiao B. Dietary saturated fat intake and risk of stroke: Systematic review and dose-response meta-analysis of prospective cohort studies. Nutr Metab Cardiovasc Dis. 2020 Feb 10;30(2):179-189.
6Schwingshackl L, Hoffmann G. Monounsaturated fatty acids and risk of cardiovascular disease: synopsis of the evidence available from systematic reviews and meta-analyses. Nutrients. 2012;4(12):1989-2007.
8Hooper L, Al-Khudairy L, Abdelhamid AS, Rees K, Brainard JS, Brown TJ, Ajabnoor SM, O’Brien AT, Winstanley LE, Donaldson DH, Song F, Deane KHO. Omega-6 fats for the primary and secondary prevention of cardiovascular disease. Cochrane Database of Systematic Reviews 2018, Issue 7. Art. No.: CD011094.
11Vegan Health. Omega-3s Part 2 – Research. Available at: Omega-3s Part 2—Research – Vegan Health
12Silva G. S. O Vegetariano – Guia Essencial Para Uma Alimentação Vegetariana Saudável, Saborosa e Descomplicada. Oficina Do Livro. 2ª edição (2020). (Book in Portuguese)
13Vegan Health. Omega-3s Part 4 – Table of Plant Fats and Oils. Available at: Omega-3s Part 4—Table of Plant Fats and Oils – Vegan Health
14Uddin K, Juraimi AS, Hossain S, Nahar AU, Ali E, Rahman M, “Purslane Weed (Portulaca oleracea): A Prospective Plant Source of Nutrition, Omega-3 Fatty Acid, and Antioxidant Attributes”, The Scientific World Journal. 2014.
15Santos HO, Howell S, Earnest CP, Teixeira FJ. Coconut oil intake and its effects on the cardiometabolic profile – A structured literature review. Progress in Cardiovascular Diseases. Volume 62, Issue 5. 2019.
16Jayawardena R, Swarnamali H, Lanerolle P, Ranasinghe P. Effect of coconut oil on cardio-metabolic risk: A systematic review and meta-analysis of interventional studies. Diabetes & Metabolic Syndrome: Clinical Research & Reviews. Volume 14, Issue 6. 2020.
18Teng M, Zhao YJ, Khoo AL, Yeo TC, Yong QW, Lim BP. Impact of coconut oil consumption on cardiovascular health: a systematic review and meta-analysis. Nutrition Reviews. Volume 78, Issue 3, March 2020.