‘Good fats’ has become an overused almost meaningless health label.

We advocate a  whole food plant-based diet – a diet built mainly on whole grains, legumes, vegetables, and fruits. This is a low-fat diet because most of the energy these foods provide is in the form of carbohydrates and proteins with only a small contribution from fat. It’s the dietary pattern with evidence for reversal of heart disease and insulin resistance and is of low caloric density, assisting weight loss. The macronutrient ratio (typically >70% carbohydrate, 10-15% protein, 10-15% fat) is a consequence of the composition of our core foods rather than the macro ratio determining our food choices.

“But what about good fats?” is a question or objection often raised when we describe our low-fat dietary approach and the amazing health results we see when people eat this way. People love their fat-rich foods, and the dairy, olive oil and nut industries have successfully dismantled the low-fat diet paradigm during the preceding couple of decades. ‘Good fats’ have gained de facto status as a food group and even many plant-based foodies seem to regard ‘good fats’ as an essential component of every meal. In mainstream nutrition Australians are being encouraged to add hundreds of calories of olive oil to their meals every day in the name of ‘good fats’. Has anyone paused to consider what a ‘good fat’ is? It would seem not when we review the composition of many of these so-called good fats.

Criteria for a ‘good fat’

Whole food: Our first criterion for a ‘good fat’ is that the fat is in the context of a whole food. Vegetable oils and margarine are not ‘good fats’ because they have lost all the fibre and most of the nutrients of their plant of origin (see our No Oil page).

Low in saturated fat: ‘Good fats’ are good because bad fats – i.e. saturated and trans fats – are bad for our health. Any ‘less bad’ fat than these are usually labelled a ‘good fat’ by nutritionists. We can sideline trans fats because they have been largely eliminated from ultra-processed foods, leaving ruminant meats and dairy as the primary dietary source. Saturated fats are widespread in both plant and animal-derived foods. The issue is how much saturated fat does it take to lose the ‘good fats’ tick of approval? The commonly accepted upper healthy limit of saturated fat intake is 10% of total dietary calories. The American Heart Association recommends an even lower target of 5% to 6% of calories from saturated fat. Adding in more calories from foods with a greater percentage of saturated fat than this (e.g. olive oil or avocado) is never going to get us to these targets. How do some common ‘good fats’ compare to these criteria?

Saturated fat as a percentage of total calories:

 

Olive oil, avocado, and many nuts owe their ‘good fats’ label to their high monounsaturated fat content. Monounsaturated fats have a neutral effect on blood cholesterol and metabolic health. We have no requirement for monounsaturated fats other than as a source of calories (energy). Plants with a high monounsaturated content may qualify as ‘good fats’ if they meet our criteria.

Essential fat ratio: The only ‘good fats’ that are essential are two groups of polyunsaturated fats, the omega 6 and omega 3 series. Human requirements for these amounts to only a few percent of daily energy intake and clinical deficiency is extremely rare. What may be more relevant is the ratio (omega-6: omega-3) as the two groups are transformed within the body by the same enzymes, and too much of one may compromise conversion of the other into the long chain form. The modern diet has become skewed towards the omega-6 group, far from the optimal ratio of 4:1 or less. This is thought to contribute to long-term adverse health outcomes. Omega-6 fats are widespread in grains, nuts, seeds, and oils and are more often present in the diet in excess. In contrast, few foods are high in omega-3 fats. The omega-6 to omega-3 ratio of the total dietary pattern is important, rather than that of individual food items. One could eat some high omega-6 meals and counterbalance these with other meals of higher omega-3 content. However, anticipating that something else will compensate for what’s currently on our plate can be a slippery slope in nutrition. Giving the ‘good fats’ tick to foods low in omega 3’s may take people further from an optimal fat ratio. Our final criterion for the ‘good fats’ label is that the item has an omega 6 to omega 3 ratio supporting a total dietary ratio of 4:1 or less. Many foods promoted as ‘good fats’ do not meet this criterion.

Omega 6 to omega 3 ratio in foods of moderate to high fat content:

*Green leafy vegetables are low in fat therefore it takes a lot of them to have a meaningful effect on your omega-3 intake.

The aim of this article was to bring nutrition science into the ‘good fats’ meme to help you make healthier food choices, regardless of where you are on the fats-starches continuum of whole foods, plant-based nutrition. Some individuals and groups may benefit from eating more ‘good fats’ to maintain an adequate calorie (energy) intake. Our personal low-fat, WFPB diet includes ground flaxseed, a few walnuts, a little peanut paste, and tahini as condiments.

Our ‘good fats’ tips:

1. Source ‘good fats’ from whole foods or minimally processed whole foods.
2. Limit consumption of ‘good fats’ with a higher saturated fat content, particularly if you have heart disease or type 2 diabetes.
3. Choose ‘good fats’ with a lower omega 6:3 ratio.
4. Balance higher intakes of omega 6 predominant ‘good fats’ with increased omega 3 foods.
5. Be mindful that high-fat foods are calorie-dense and good for weight gain.

Related pages:

• Why do we recommend a low-fat diet?
• Omega 3 Essential Fatty Acids
• No oil!
• What’s wrong with saturated fat?
• Energy density
• Low fat diets for weight loss

Resources

• Australian Food Composition Database – Click on ‘Searchable database’ to search for data on the nutrient content of Australian foods.
• FoodData Central – Search for US food data.

 

Page created 30th December 2023
Last updated 5th January 2024

Australia lagged behind the rest of the world in approving the sale of hemp seeds for human consumption in late 2017. Before this, the sale of hemp seeds was legal, provided it was for use in cosmetics or other non-food use (hence the sticker on the packet above, purchased in 2017). Hemp seeds became widely available in Australia in 2018. Many people rank hemp seeds as higher in omega-3s than they really are, sometimes giving it a ‘superfood’ status. As with any other edible seeds, we recommend that if you are going to eat hemp seeds, you eat whole or ground seeds and not processed food products such as hemp seed protein and hemp seed oil.

Hemp seeds are produced from non-intoxicating varieties of the hemp plant and do not contain significant cannabinoids. We have reviewed the nutrition composition of hemp seeds and compared them to several other nuts and seeds, particularly regarding their omega-3 essential fatty acid content. The USDA data that we used was similar to the nutrient data listed on two different brands of hemp seed we found in retail outlets.

Protein and other nutrients:

• Hemp seeds are much higher in protein (22% of calories) than flax or chia but lower than legumes.
• Flax and chia are far higher in dietary fibre than hemp, and the fibre in flax (lignins) assists the body in excreting excess estrogens.
• The calcium content of the seeds ranged from very high for chia, moderate for flax and low for hemp.

Omega 3’s (alpha linolenic acid):

Many people have sub-optimal intakes of omega 3’s and perhaps more importantly, unfavourably high ratios of dietary omega 6 to omega 3. This is the result of low intakes of omega-3 rich plants combined with high intakes of omega-6 rich plants such as nuts, seeds, avocados as well as vegetable oils. An optimal omega 6 to 3 ratio is 4:1 or less.

For a whole food omega 3 source to bring the dietary omega 6 to 3 ratio into balance, it needs to have a ratio well below the target of 4:1. Flax (ratio 1:4) and chia (ratio 1:3) have more omega 3’s than 6’s and are therefore excellent sources of omega 3 fats. Hemp seeds (3:1) and walnuts (4:1) might be considered good sources on their own, but not good enough to compensate for the omega-6 rich foods in the typical vegan diet. For more on omega 3’s see our Omega-3 Essential Fatty Acids page.

The following table gives comparative data for four high omega-3 nuts and seeds:

Per 100 g	Flax	Chia	Hemp	Walnut
Calories	534	490	553	765
Fibre (g)	27.3	37.7	4.0	7.8
Protein (g)	18.3	15.6	31.5	17.8
Calcium (mg)	255	631	70	115
Carb: Fat: Protein (% Cal)	22:66:12	36:53:11	6:72:22	9:83:8
Omega 3 (g)	22.8	17.5	9.3	8.7
Omega 6 (g)	5.9	5.7	30.9	27
Omega 6 : 3 ratio	1 : 3.9	1 : 3.1	3.1 : 1	4.1 : 1

The Australian recommended intake of omega-3 fatty acids is 0.8 grams per day for women and 1.3 grams for men (see Nutrient Reference Values for Australia and New Zealand).
This is easily met by consuming 10g of flax or chia per day.

Hemp seeds have a more favourable fatty acid profile than most other nuts and seeds but fall well behind flax and chia seeds as a concentrated source of omega-3 fats. They have a mild taste and relatively soft texture which makes them suitable as an ingredient in a variety of dishes. Hemp seeds, like other nuts and seeds, can be a healthy addition to a whole foods, plant-based diet but are best consumed in small amounts.

See also:

• Omega-3 essential fatty acids

Resources

• National Health and Medical Research Council. (2006). Nutrient Reference Values for Australia and New Zealand: Including Recommended Dietary Intakes. Canberra: NHMRC
• USDA Food Data Central

Page created 26 February 2018
Page last updated 2 March 2019

• Omega 6:3 ratios
• Resources

A whole foods, plant-based diet can provide all the essential fats we need. These are the omega-6 and omega-3 groups of polyunsaturated fatty acids. There is no dietary requirement for other polyunsaturated fats, monounsaturated fats or saturated fats other than as an energy source. Omega-6 fats (linoleic acid) are plentiful in our diet. It’s the omega-3 group that has become a nutrient of concern.

Essential fatty acid requirements

Human requirements for omega-6 and omega-3 fats are uncertain because deficiency states are rarely seen. Dietary requirements are given as an ‘adequate intake’ rather than a minimum requirement. Adequate intake is used when an RDI cannot be determined and is based on an average intake of an apparently healthy population. [see Nutrient Reference Values: Fats: Total Fats & Fatty Acids for Adequate Intake (AI) recommendations]

The ratio of omega-6 to omega-3 fats is more relevant than the absolute amount of each, and herein lies the problem. The modern food supply is overloaded with omega-6 fats and often low in omega-3 fats with ratios of 15-20:1. The optimal ratio of 6’s to 3’s is generally considered 4:1 or less. Many foods promoted as ‘good fats’ have an overabundance of omega 6’s. (See our FAQ What are good fats?).

Omega 6:3 ratios of common foods

*Green leafy vegetables are low in fat therefore it takes a lot of them to have a meaningful effect on your omega 3 intake.

Fatty Acid Chemistry

Plants provide linoleic acid (omega-6) and alpha-linolenic acid (ALA)(omega-3). Our cells have enzymes that convert these to arachidonic acid (AA)(omega-6 fat), EPA (omega-3) and DHA (omega-3). (Cats are carnivores and lack this enzyme). Arachidonic acid (AA), eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) are substrates for cell membranes, and a large group of signalling molecules called eicosanoids that have powerful local effects in many different organs. Omega-6 fats are essential for inflammatory processes and blood clotting. Omega-3 fats are required in smaller amounts and are often considered anti-inflammatory, but this is an oversimplification.

Is there a dietary requirement for DHA?

The efficiency of the human enzyme that initiates the conversion of plant-based omega-3 (alpha-linolenic acid) into the long-chain forms (EPA, DHA) has been called into question. Only a few percent of plant-based ALA is converted to DHA. Estimates of the conversion rate vary widely and are found to increase when requirements are greater, such as during pregnancy. Omega-3 and omega-6 fats are processed by the same enzyme, and an excessive dietary intake of omega-6 fats reduces the conversion of omega-3s despite the enzyme having a greater affinity for omega-3s. Theoretically, flooding the body with excess omega-3 fats might also impair arachidonic acid production. We are confident that a plant-based diet with a reasonable omega-6 to omega-3 balance will allow the body to make just the right amount of AA, EPA and DHA to meet its needs. The body controls DHA levels through a feedback mechanism that suppresses one of the steps in the DHA synthesis pathway (EPA -> DPA), ensuring that it does not produce more DHA than it needs. We can push DHA to much higher levels than the body would produce by eating fish or taking supplements.

No absolute requirement for DHA has been established. The controversy is over whether taking preformed DHA (from fish or microalgal supplements) leads to better health outcomes.

Measuring omega-3 in the food and the body

Dietary analysis is unreliable for measuring dietary intake of omega-3 because food composition tables do not have an omega-3 value for many foods, thus underestimating true intake.

Blood tests for omega-3 levels are popular and often offered by the same corporate groups that sell omega-3 supplements. Test results are presented as a numeric value and compared to a reference range and suggest an optimal level of the omega-3 index between 8-12%. As of December 2024, we have not found any scientific rationale for these suggested ‘optimal’ levels.

Risks and benefits of omega-3 supplementation

Heart disease: Several meta-analyses and reviews have failed to find a protective effect of omega-3 supplementation on cardiovascular disease (e.g. The Risk and Prevention Study Collaborative Group, 2013 ). Some studies have observed better health outcomes in people who eat fish. However, this is probably because of what fish replaces, e.g. Red meat and because fish intake is often an indicator of a healthy diet and lifestyle.

Omega-3 supplementation is associated with an increase in atrial fibrillation, a common heart arrhythmia that can lead to stroke (see Gencer et al 2021).

Brain health: Having failed to protect the heart, omega-3 supplements are now being promoted for brain health. The brain preferentially takes up omega-3 fats and concentrates them in cell membranes. In this regard, omega-3s are essential for brain health, but more may not be better. Although the brain contains a lot of DHA (4g), the daily uptake of DHA from the blood is only 4mg. The issue of EPA/DHA supplementation is controversial among plant-based advocates. The research is mired in conflicts of interest, small changes of low clinical significance, and research subjects with poor-quality baseline diets.

Diabetes: There is an increased risk of diabetes in those who take fish oil supplements or eat fish.

Prostate cancer: Fish oil supplementation and fish intake is associated with an increase in prostate cancer risk. It’s possible that some of this risk may be attributable to the high levels of PCBs and other organic pollutants found in fish and fish oil supplements (see Sorongon-Legaspi et al 2013)

Premature birth: There is evidence that DHA supplements given to women with singleton pregnancies from 12 weeks reduce the risk of premature birth. The author wonders whether this effect is offsetting the high arachidonic acid intake of omnivores.

Bleeding disorder: Very high intakes of oily fish, such as the traditional Inuit diet, or excessive intake of supplements cause prolonged bleeding times due to impairment of blood clotting.

Osteoporosis: Some studies report that high blood DHA levels are associated with osteoporosis (see Li et al 2024). Others report healthier bones in subjects with a lower (more favourable) ratio of Omega-6 to Omega-3 in their blood. In the latter, the plant-based omega-3 (alpha-linolenic acid) was associated with a lower rate of bone loss (see Feehan et al 2022).

Take home points

• Dietary omega-3 requirements are controversial among plant-based advocates.
• Blood tests are not clinically useful because there is no evidence-based reference range.
• Omega-3 brain research is mired by conflicts of interest and clinically insignificant results.
• Humans can synthesize EPA and DHA (and arachidonic acid) in adequate amounts provided dietary essential fatty acids are in reasonable balance.
• EPA and DHA supplements may be harmful, particularly in higher doses.
• Dietary strategies can ensure that essential fatty acid needs are met.
• A microalgael DHA supplement may be appropriate in some situations. A smaller dose may be a safer option.

Dietary strategies for adequate omega-3

• Minimise intake of vegetable oils, particularly polyunsaturated oils such as sunflower oil, a common ingredient in plant milks and other processed foods.
• Eat nuts, seeds and avocados in small quantities, and shift your diet towards the lower fat end of the whole plant macronutrient spectrum, tubers, whole grains and legumes.
• Include some high omega-3 nuts/seeds with your meals, for example, flax or chia seed. Leafy green vegetables provide some omega-3 fats.
• If you choose to eat higher quantities of nuts, seeds and avocados, include plenty of moderate to high omega-3 plants.
• See our FAQ: What Are Good Fats?

 

See related pages:

• What are ‘good fats’?
• Are hemp seeds a good source of omega-3?
• No Oil
• Vitamins and Minerals
• Why do we recommend a low-fat diet?

Resources

• Omega-3 Fatty Acid Supplementation: Is it Beneficial? Dr. Tim Radak – *NEW* I Am Human Podcast #320.
• Omega 3, diet and lifestyle factors influencing brain health and risk for cognitive disease and impairment and relevance to vegan diets – *NEW* By Dr. Tim Radak, May 2021 (continually updated – last update September 2024). Extensive article looking at research on omega 3 and brain health.
• Do vegans and vegetarians require a DHA supplement? – Dr Tim Radak (1hr video). Conference presentation in 2019.
• DHA: On Further Thought – Dr. Michael Klaper (20 min video)
• Should You Worry About DHA? – Jeff Nelson
• Do Vegans Need DHA Supplements? – Jeff Nelson (1hr video) Looks at the research around omega 3 fatty acids, including the body’s ability to convert omega 3 to the long chain form and the risks and benefits of DHA supplementation. 
• Are Omega-3 Supplements Necessary? – Dr Linda Carney
• Increased Omega-3 Fatty Acids Intake Useless for CVD – Pam Popper (12 min video). Pam regularly reviews the science on omega 3 supplements and continues to find there is no benefit in supplementing.
• No benefit of omega-3 supplements for depression or anxiety – Robyn Chuter (2019)
• Do You Need to Supplement With EPA and DHA If You Follow a Whole Food Plant-Based Lifestyle? – Dominic Marro, RD (2016)
• Omega 3 – Discussion by Jeff Novick, RD on the conversion rate of ALA in the McDougall Discussion forum
• NIH study shows no benefit of omega-3 or other nutritional supplements for cognitive decline (2015)

Peer-reviewed articles

• The Risk and Prevention Study Collaborative Group. (2013). n–3 Fatty Acids in Patients with Multiple Cardiovascular Risk Factors. New England Journal of Medicine, 368(19), 1800-1808 – “…there was no significant benefit of n−3 fatty acids in reducing the risk of death from cardiovascular causes”
• Chew, E. Y., et al. (2015). Effect of Omega-3 Fatty Acids, Lutein/Zeaxanthin, or Other Nutrient Supplementation on Cognitive Function: The AREDS2 Randomized Clinical Trial. JAMA, 314(8), 791-801.
• Feehan, O., Magee, P. J., Pourshahidi, L. K., Armstrong, D. J., Slevin, M. M., Allsopp, P. J., . . . McSorley, E. M. (2023). Associations of long chain polyunsaturated fatty acids with bone mineral density and bone turnover in postmenopausal women. European Journal of Nutrition, 62(1), 95-104.
• Gencer, B., Djousse, L., Al-Ramady, O. T., Cook, N. R., Manson, J. E., & Albert, C. M. (2021). Effect of Long-Term Marine ɷ-3 Fatty Acids Supplementation on the Risk of Atrial Fibrillation in Randomized Controlled Trials of Cardiovascular Outcomes: A Systematic Review and Meta-Analysis. Circulation, 144(25), 1981-1990.
• Hooper, L., et al. (2006). Risks and benefits of omega 3 fats for mortality, cardiovascular disease, and cancer: systematic review. BMJ, 332(7544), 752-760 – “…omega 3 fats do not have a clear effect on total mortality, combined cardiovascular events, or cancer”.
• Kaushik, M., et al. (2009). Long-chain omega-3 fatty acids, fish intake, and the risk of type 2 diabetes mellitus. American Journal of Clinical Nutrition, 90(3), 613-620 – “…higher fish and long-chain omega-3 fatty acid consumption appears to be associated with a modestly but significantly higher incidence of T2DM”
• Li, L., Wen, Y., Liu, D., Lan, J. P., & Yang, B. (2024). Causal link between docosahexaenoic acid and osteoporosis: A 2-sample Mendelian randomization study. Medicine (Baltimore), 103(32), e38893.
• Schaefer, E. J., Bongard, V., Beiser, A. S., Lamon-Fava, S., Robins, S. J., Au, R., . . . Wolf, P. A. (2006). Plasma phosphatidylcholine docosahexaenoic acid content and risk of dementia and Alzheimer disease: the Framingham Heart Study. Archives of Neurology, 63(11), 1545-1550.
• Simopoulos, A. P. (2008). The importance of the omega-6/omega-3 fatty acid ratio in cardiovascular disease and other chronic diseases. Experimental Biology and Medicine, 233(6), 674-688.
• Sorongon-Legaspi, M. K., Chua, M., Sio, M. C., & Morales, M., Jr. (2013). Blood level omega-3 Fatty acids as risk determinant molecular biomarker for prostate cancer. Prostate Cancer, 2013, 875615.
• Welch, A. A., et al. (2010). Dietary intake and status of n-3 polyunsaturated fatty acids in a population of fish-eating and non-fish-eating meat-eaters, vegetarians, and vegans and the product-precursor ratio [corrected] of alpha-linolenic acid to long-chain n-3 polyunsaturated fatty acids: results from the EPIC-Norfolk cohort. American Journal of Clinical Nutrition, 92(5), 1040-1051.

Return to Vitamins and Minerals page

Page created 22 June 2013
Last updated 23 December 2024 (major revision); minor revision 26 January 2025

• Resources

Specific vitamins, minerals and other nutrients:

• Vitamin B12
• Vitamin D
• Calcium
• Iron
• Iodine
• Omega-3 essential fatty acids
• Protein

Most vitamin and mineral supplements are of no benefit and some may be harmful. With few exceptions we recommend that you get your vitamins, minerals, fibre and other phytonutrients from minimally processed plant foods. The supplements that may be required are related to modern living conditions rather than any inherent deficiency of a plant based diet. Clean food and water and safe food handling, whilst preventing disease, may remove most of the bacteria-derived vitamin B12 from our food supply. Indoor living can deprive us of the UV rays that are required for vitamin D synthesis. Many people take supplements as an insurance policy against dietary inadequacy or to detoxify the effects of too many rich foods. Unfortunately, supplements neither emulate the benefits of nutrients from plants, nor detoxify the harmful effects of excess animal protein, fats and processed foods.

Whole food is complex (see ‘Whole’ by T Colin Campbell in resources below). Our understanding of it is very basic. We know which nutrients are absolutely essential for life and the approximate amounts required. We have identified only a small number of the thousands of other biologically active substances in plants (known as phytochemicals or phytonutrients). We know little of the interactions between these various nutrients and phytonutrients. Often a high intake of a particular nutrient from food is associated with a health benefit, such as less cancer, but when we give them as supplements rather than as whole foods the benefit may be absent or reversed, increasing cancer risk.

There are some medical conditions in which vitamin supplements can be used as a pharmaceutical. Several of the B group vitamins can assist in reducing high homocysteine levels and this has been shown to reduce the progression of the early stages of dementia (see VITACOG study). The dietary approach would be to remove the cause of the elevated homocysteine levels by reducing animal protein consumption. While on the topic of dementia, Dr Neal Barnard recommends a vitamin B12 supplement and advises against taking supplements that contain minerals such as iron, copper and zinc as high levels of these may damage the brain.

No particular food has exclusive ownership of any particular nutrient. You do not need dairy foods for calcium, red meat for iron or fish for omega 3 oils. You do not even need to know which foods are the “best” sources of any particular nutrient. You just need to eat enough calories of whole grains, legumes, vegetables and fruits to maintain a healthy weight. And if you wish to tweak your plant-based diet to include more omega-3s, iodine, resistant starch or any other nutrient or phytochemical then we suggest that you bypass the supplements and just find some whole plant foods rich in the particular phytonutrient and make them a regular part of your diet.

See video: Dr. John McDougall Medical Message: Vitamin Supplements

Last updated 11 April 2015