Doctor's Note

Some recent videos on the beneficial fats in plant foods:

And learn more about the negative effects of saturated fats in these videos:

Some recent videos on the most damaging fat of all, trans fat:

And check out my other videos on fat.

If you haven’t yet, you can subscribe to my videos for free by clicking here.

To post comments or questions into our discussion board, first log into Disqus with your account or with one of the accepted social media logins. Click on Login to choose a login method. Click here for help.

  • Michael Greger M.D.

    Please feel free to post any ask-the-doctor type questions here in the comments section and I’d be happy to try to answer them. And check out the other videos on fat. Also, there are 1,449 other subjects covered in the rest of my videos–please feel free to explore them as well!

    • My program advocates low fat diets, avoiding all oils (we know those are bad!), and, eating nuts and seeds only in limited amounts. Some physicians state that they must be avoided totally. Research and other nutrition physicians state that nuts and seeds, eaten with other foods (as in salad dressings and smoothies), are necessary for proper absorption of important micronutrients. Consuming totally low fat foods can lead to impaired immune function. I’ve check the research, but would appreciate further input if you have any.

  • VegeMarian

    I’m dismayed that the author of the report effectively concedes that the science shows a vegan diet is best (with regard to trans fat intake) but he is unwilling to endorse it because it’s “a bit extreme.” The authors could help so many people by simply making recommendations consistent with their research. It shows just how strongly conditioned we are to eat animal products. It’s unfortunate that top scientists are no exception.

    • Karen A

      ” The authors could help so many people by simply making recommendations consistent with their research. It shows just how strongly conditioned we are to eat animal products. It’s unfortunate that top scientists are no exception.”


      And it’s seen as extreme because these people are not out there making sure that accurate information is being made mainstream. Vicious circle.

      • barbarabrussels

        First reactions I hear upon becoming whole food vegan, that’s a bit extreme! :-) I don’t argue, I’m happy, I just say ‘If you say so…’ I just hope my improved health (after just 2 weeks) will inspire them and some of it will sink in.

  • lbateman

    Yes, it’s so crazy … medical leaders can all be saying now ‘we all have no choice but to go vegan, and change is not that hard’, then watch out for the amazing health & enlightenment ahead.
    Meditation, reflection, reverence for science results, and ethical ways are the only worthwhile way.
    ~ A Vegan Nurse.

  • BPCveg

    I found a fascinating study (Innis and King, Am J Clin Nutr 1999;70:383–90; PMID=10479201) that provides compelling evidence that the breast milk of Canadians mothers contains up to 18.7% trans-fats (avg. was about 7%) and that these high concentrations are reflected in the blood concentrations of trans-fats of their breast-fed infants.

    Also possibly of relevance to this topic was the finding that approximately 20% of the trans-fats in the mother’s milk originated from dairy and meat sources, according to Table 4 of that paper.

  • br85
    “…Most importantly, however, the naturally occurring trans fats have not, as they occur in animal fats, been shown to share the harmful properties of the synthetic trans fat resulting from hydrogenation. This does not mean that all the trans fatty acids are in themselves harmless, but that any harmful effect is limited and balanced by the beneficial effects of, for example, trans isomers of conjugated linoleic acid (CLA) which are health-promoting with specific roles to play in our bodies. Also vaccenic acid, the main ‘natural’ trans fatty acid, can be metabolised by humans to CLA.”

    Sometimes it’s just not as simple as it seems, and there may, in fact, be a reason that people who eat junk food seem to suffer more than those who live on an almost all-meat diet. Science still seeks truth, but incomplete science is bad science, and unfortunately, should never be used to support a viewpoint we already had for unrelated reasons.

    • DrDons

      Unfortunately all science is incomplete as the science is continually changing…. sometimes leading us to a shift in our beliefs or paradigm and sometimes continuing to confirm our beliefs. I don’t believe science seeks the truth… only the best hypothesis given the science at the time. If we believe we have the “truth” we risk becoming trapped in our own belief system like “I need to consume animals to get quality protein” or consumption of foods high in protein is “good” or “milk does the body good”. I would say it is never simple as human nutrition is very complicated and worse these complicated processes occur in systems that are complex and adaptive. So we are stuck with developing beliefs that help us navigate the increasingly complex world. I think on balance current science supports the avoidance of trans fat whether synthetic or “natural”. I believe the best recommendation at this point is to avoid both animal products and processed foods(foods with labels). But keep tuned to as the science is constantly changing.

  • I used something called “Copha” – ingredients Hydogenated coconut oil , soya bean lecithin in a vegan baked treat. Is this the killer “trans fat”?

    • Alexandra Georgiadis

      Hi Heidi,
      When oils are fully hydrogenated they contain almost no trans fats. They do however usually contain more saturated fat. These more solid fullly hydrogenated fats, although not the healthiest fat choice, are not the “killer” trans fats. It is the partially hydrogenated oils that you should stay away from; they contain the trans fats.
      Now to answer your question about Copha: I am not familiar with this product, but it is important to be aware that sometimes packages simply say “hydrogenated oils” and do not specify whether they are partially or fully hydrogenated, leaving the consumer unsure of whether it contains transfats. It might be a good idea to research this product to be sure that the coconut oil is fully hydrogenated. Another important thing to note is that companies can label their products “trans fat free” even when partially hydrogenated oils are listed in their ingredients. They get away with this because, under FDA regulation, if there is less than 0.5 grams of trans fats per serving than it can be deemed trans fat free. The problem here is not only that we are consuming traces of trans fats when we’re led to believe we are not consuming any, but we often eat more than 1 serving in one sitting; I know I do! I hope this helps.
      If you’re interested, here are some more links on fats and fat products/supplements:

      • Jo

        i emailed the Copha company they advised that it is 0.8g of trans fats per 100g, In Australia, (where Copha is from) there is no legal requirement to put trans fats on our nutrition labels

  • Toxins

    How come the Paper from the national academies of science also says that avoiding meat and dairy may cause inadequate protein intake. Why would they even mention this?

  • Ashish

    Here is a new interesting study: Trans fat consumption and aggression.

  • leena j dsouza

    i have a back problem some times it cathes vry hard i cant spear it

  • Len Brown

    I grind flax seed before cooking mixed bean dishes.
    Does cooking destroy the benefits of flax oil ?

    • Important to grind the flax seed. Cooking should not destroy benefit of flax seed… based on current studies… keep tuned in you never know when a study will come out challenging our beliefs.

  • Bryan

    Has anyone noticed the similarity of the chart showing the volume of industrial production of transfats since they were invented and the chart of heart attack deaths over the same period?

  • liohina

    You talk about avocados containing healthy monounsaturated fat, but you never mention that their ratio of omega 6 to omega 3 fatty acids is 15 or 16 to 1…definitely not good. All that and persin too??? (Sob!).

    –Inveterate avocado lover

    • Penny

      You can still consume foods with that sort of Omega 3/6 ratio, you just need to make sure to get more Omega 3 from another source. Two tbsp. of flaxseed every day keeps my ratio at 2:1 even though many of the foods I eat are higher in 6 than 3. You can’t just look at the ratio when choosing a food item. Sometimes a ratio of 15:1 is simply because there are 0.1g of omega 6 and so little omega 3 that it shows up as 0.0g.
      A good example of this is sweet potatoes. I know avocado is a bit higher in both omega 3 and 6 (0.2g, 2.3g), but even if you ate both in the same day, two tbsp. of ground flaxseed would bring your ratio back to around 1:1, depending on what else you have eaten.

  • jshm

    Dear Dr. Greger,

    Historically margarine has had high levels of trans fatty acids but modern spreads tend to have little or no trans fatty acids (listed as 0 g). Although, based on the FDA nutrition labelling this actually refers to less than 0.5 g of trans fat per serving. In addition, the saturated fat levels are much lower than butter. You mention that no amount of trans fat is advised, but is less than 0.5 g per serving negligible? And based on the low levels of trans fat and saturated fat, are vegan spreads an acceptable part of a standard diet?

    Best wishes,


  • Marshall Schools

    Soooooo how do you consider the fats to be different in grass fed meat and dairy? Or processed plant foods? So saturated fats in coconut oil? Coconut oil, at least organic unfiltered versions, are really healing. I’ve experienced it and so have many of my friends. How do we distinguish between the good and bad versions of each type of fat depending on how that food is treated?

  • vkat79

    Dear Dr. Greger, dear nutritionfacts community,

    Even after
    having watched a number of videos (also by Dr. Esselsytn), I still
    don’t seem to comprehend what the problem with oils is. I mean, not all
    of them are hydrogenated, right?
    I assume (or hope) there is a difference between consuming them with your meals and treating your hair or skin with oils?
    is it a bad thing to put hazelnut / avocado / olive / castor / … oil
    on my skin for an over-night treatment? Or putting some oil on my hair
    tips? Or putting it on my elbows when the skin is dry?
    And what about oil pulling?
    sure not all oils were created equally bad? Are grape seed oil and
    poppy seed oil as bad as safflower oil, even though it’s also high in
    PUFAs? I mean, I do get the whole foods approach, I’m a big fan myself!,
    butI love oil-lemon dressings for my salad, and I love using walnut
    oil, for example. I don’t use much oil, though.
    (Example: carrots, walnut oil, fresh lemon juice, chopped hazelnuts, pepper)

    I’d really love some answers … I’m confused and don’t know what to do :/

    THANKS in advance!


    • Thea

      VKat: I recently re-watched a video from Jeff Novick called “From Oil to Nuts”. This video did an EXCELLENT job of really explaining why you might want to stay away from all oils. I highly recommend the video.

      Some of the highlights include:
      * most oils are going to have too much omega 6s to omega 3s
      * oils are empty calories – worse than sugar when you do a comparison
      * oils are the high calorie-dense, a big problem for people who need to lose weight
      * oils which tend to have a better omega 3 ratio (say flaxseed) go rancid very, very quickly. (In fact, Dr. Greger has at least one video on common oils and how quickly they go rancid. You might want to find that one if you can. It’s really eye-opening.)
      * oils/high fat make your blood sluggish (I think that point was in the Jeff video)

      Having said all that, here is how I have personally synthesized the information I have seen on oils: It is best to avoid them if I can because of all of the reasons stated above, plus more. However, just like it is best to avoid sugar, that doesn’t mean that I will never eat sugar. I just try to limit it as best I can. That’s my personal decision.

      So, in the context of a truly healthy whole plant food based diet, I don’t think it would be all that bad if you have some (non-rancid!, good luck with that) walnut oil. (The key would be to keep it as minimum as possible. Or maybe some days make your dressing without the oil and other days have it in?)

      That’s my 2 cents anyway. Hope it helps.

      • vkat79

        Thea, thank you *soooo* much! :) I’ll watch the recommended video! Thanks for summarizing the main points :) Very kind of you!!

        I love this community & the spirit!

  • David Folster

    I have a question regarding omega 3:Omega 6 ratio. If a lower/equal ratio of omega 6:omega 3 is optimal for health, then why are concentrated sources of omega 3 so scarce in nature? You can count them on one hand. Even foods that have been shown to improve endothelial function, such as pistachios and sesame seeds, have an extremely high omega 6:omega 3 ratio.

    So my question is this: might it be the case that, in the same way that the saturated fat in coconut oil is not harmful whereas the saturated fat in whole coconut is neutral, and the omega 3 in flax oil is neutral but the fat contained in whole flax is beneficial…might it only be refined omega 6 oils that are harming us and not the omega 6’s found in whole foods such as avocados, nuts and seeds?

    • Toxins

      Hello David. The answer is no, and here’s why.

      Yes the ratio is important and yes it is true that omega 3 rich foods are not abundant, but this is not significant if one is eating a very low fat, whole foods plant based diet. Omega 3’s naturally occur in whole plant foods. The requirement for men is 1.6 grams and for women 1.1 grams of omega 3. This can generally be reached over the course of a day. In nature, nuts flourish in the winter and are not available year round. The outer shells are much more difficult to access as well, and these shells are not the very last layer of protection as conventional nuts are sold today. Most nuts have a very tough husk. Leafy greens have an especially high amount of omega 3, as well as several beans, such as kidney beans and several fruits. A whole food, low fat plant based diet will provide adequate omega 3 and also provide a good ratio.

      Coconut oil is actually harmful, the sensationalized fad of coconut oil saturated fats being negligible is not accurate.

      • David Folster

        Thanks for your reply. There appear to be two schools of thought regarding vegan diets – those who advocate low fat and those who advocate the addition of high fat whole foods plant sources of fat such as nuts and avocados. According to his videos, Dr. Greger does not advocate a low fat whole foods plant based diet, but rather a whole foods plant based diet that includes whole foods sources of fat such as nuts, seeds and avocados. See the 2 videos below.

        I understand that coconut oil is bad for you, however one of Dr. Greger’s videos details how coconut as a whole food, despite being high in saturated fat, has a neutral effect on health. See:

        Hence my original question stands.

        • Toxins

          Dr. Greger does not personally advocate a specific diet, he just shares the evidence. As a moderator, we are specifically told that Dr. Greger advocates no specific diet.

          The studies on nuts are done mostly on those who are already quite unhealthy so it is difficult to state that those consuming a low fat whole foods plant based diet will benefit. In addition, the study Dr. Greger shared on coconuts was a single study on a population and we cannot extrapolate too much on this. Lets remember that heart disease has only ever been reversed on a very low fat diet, and that saturated fat independently has been implicated in MS.

          As Jeff Novick has put it

          “Move Over Walnuts, Kale, Goji Berrries, Sweet Potatoes, Purple Cabbage, etc., & Make Room For The Next Super Food: Carrots!

          “Carrot intake might be inversely associated with prostate cancer risk.”

          When you understand that the typical diet consumed today is **so** bad, possibly being the worst diet ever consumed by humans in recorded history, then you understand that you can look at a group of those eating this diet and take *any* one healthy (or healthier) food (or food with some healthier aspects to it), and look at those who eat more of it compared to those who eat less of it (or none of it) and almost always see a difference. But that does not make it into a health food, let alone a super food. ”

          If we want to use populations as an example, the most long lived population, the Okinawans, had the most centenarians per capita in the 1950’s.

          As Jeff Novick has shared

          Caloric Restriction, the Traditional

          Okinawan Diet, and Healthy Aging

          The Diet of the World’s Longest-Lived People and Its Potential Impact on Morbidity and Life Span

          Ann. N.Y. Acad. Sci. 1114: 434–455 (2007).

          TABLE 1. Traditional dietary intake of Okinawans and other Japanese circa 1950

          Total calories 1785

          Total weight (grams) 1262

          Caloric density (calories/gram) 1.4

          Total protein in grams (% total calories) 39 (9)

          Total carbohydrate in grams (% total calories) 382 (85)

          Total fat in grams (% total calories) 12 (6)

          Saturated fatty acid 3.7

          Monounsaturated fatty acid 3.6

          Polyunsaturated fatty acid 4.8

          Total fiber (grams) 23

          Food group Weight in grams (% total calories)


          Rice 154 (12)

          Wheat, barley, and other grains 38 (7)

          Nuts, seeds Less than 1 (less than 1)

          Sugars 3 (less than 1)

          Oils 3 (2)

          Legumes (e.g., soy and other beans) 71 (6)

          Fish 15 (1)

          Meat (including poultry) 3 (less than 1)

          Eggs 1 (less than 1)

          Dairy less than 1 (less than 1)


          Sweet potatoes 849 (69)

          Other potatoes 2 (less than1)

          Other vegetables 114 (3)

          Fruit less than 1 (less than 1)

          Seaweed 1 (less than 1)

          Pickled vegetables 0 (0)

          Foods: flavors & alcohol 7 (less than 1)

          Data derived from analysis of U.S. National Archives, archived food records, 1949 and based on survey of 2279 persons.

          Some points

          Their diet was 85% carb, and 6% fat. Sweet potatoes (a Japanese sweet potato) made up almost 70% of their calories.Nuts were less than 1% of calories (the equivalent of 1/10 of an ounce a day) Oil was less than 2% of calories (which is about 1 tsp a day) and sugars were less than 1% of calories (less than a tsp a day)

          The total animal products including fish was less than 4% of calories which is less then 70 calories a day. That is the equivalent of around 2 oz of animal products or less a day

    • Thea

      David: I recently re-watched a video from Jeff Novick called From Oil To Nuts. One of the discussions in the video is about omega 3. One of Jeff’s points is that your basic greens like brocolli (if I remember correctly), etc. have some omega 3 ***and the ratios are perfect.*** Of course, there is very little fat at all, let alone omega 3, in a single serving of say brocolli, BUT as Jeff Novick says, “Who’s asking you to eat only one serving!” If you had say 9 servings of of those veggies on his chart over the course of the day, you could hit your omega 3 minimum, or also take a tablespoon of flaxseed as insurance if you want. With an otherwise oil-free diet, you could then afford to get in an ounce of other type of nut/seed where the ratio is off because you have such a good intake otherwise. (Hopefully I am summarizing correctly. I highly recommend watching that video if you can.)

      This information does not address exactly how much fat a person should take. (High? Low? What are those anyway?) But it does address the issue of the desirable omega 3 and 6 ratios existing naturally in nature. Apparently they do existing just great – but in small quantities in foods that you would ideally eat large amounts of.

      That’s my understanding anyway. Hope that helps.

      • David Colin

        It does. Thank you!

  • Lily

    I’m really confused here, because earlier I learned that some oils are good and beneficial for you, but now I’m hearing that adding oils to your diet is harmful to your cardiovascular system and damages your arteries. I just started changing my diet about two weeks ago, slowly moving towards eating more of a WFPB diet, so I need clarification, please. Which is right? Should we eat oil or not? Thanks.

    • Thea

      Lily: Congratulations on moving toward a WFPB diet. That can be a big change for people, and the oil issue is just one more big factor on top of everything else.

      You will definitely find sources that tell you that some oils are good for you. But I have been convinced this notion is 100% wrong. You list one very good reason. In Jeff Novick’s talk, From Oil To Nuts, he explains in compelling detail (and with lots of humor) why eating any oil is not good for you. As Jeff says, (paraphrasing from memory) “Regardless of what the marketing says, if the numbers show that oil is worse than sugar, then oil is junk food.” He covers that issue and more. Unfortunately, this talk is not available for free. But I found it extremely helpful and well worth acquiring:

      Having said that, if you are in the middle of transitioning to a WFPB diet, you might cut yourself a little break on the oil issue. If you are already making many other changes in your diet, cutting out all oil can be extremely difficult to do on top of everything else. My suggestion is to keep the idea of an oil-free diet as a long term goal in the back of your mind. Cut out the meat, dairy and eggs now, but slowly work to find ways to eliminate oil from your diet. There are all sorts of tips and tricks out there on how to do that. I found that I personally have not eliminated oil 100%, but I have cut back *dramatically* compared to previously and am always working to cut out more.

      Please know that I am not a doctor nor an expert. This last thought is just my own lay person’s suggestion, which may or may not be a good one for your situation.

      Hope that helps.

      • Wade Patton

        That’s what worked for me. I allowed myself to use up my supply of olive oil on the weekends and then simply quit using oils. It’s not that difficult.

  • cyndishisara

    Trans-fats kill and the question is why? Could it be that they get incorporated into cell membrane structures so making the membrane leaky to free radicals? I think it is important to have the answers because it would help people to get it. The point is not about a little bad it is about none. Secondarily, I wonder what concentration of trans-fats are in lets say steak from grass fed steer versus factory fed steer?Mind you I am a vegan.

  • Tobias Brown

    Does Dr Greger mention anywhere a recommended percentage range level for fat macronutrient?

    • Wade Patton

      Whole foods, plant-based eating eliminates any need to count calories or grams of anything at all. So long as you keep your plant fiber and fat in the same package, all should be good. It’s the processing to make oils or incomplete flours, etc. that destroys the balance that we _really_ evolved eating, and still works to best results in our bodies.

  • Michael bloom

    I am trying to find information on Conjugated Linoleic Acid. Is it cancer fighting? And is it found in grass fed beef?

    Are there studies that separately evaluate the health risks of red meat for organic grass fed meat versus grain fed?


  • Psych MD

    FDA finally bans trans fat…….starting in 2018.

  • Miroslav Kovar

    Does Dr. Greger anywhere address the fact that most nuts and seeds are high in Omega-6s, phytic acid and many antinutrients? I don’t understand how he can approve of a food containing such harmful chemicals.

    • Thea

      Miroslav Kovar: Dr. Greger did a series on phytates. The good news is that despite what you read on the internet, phytates are likely good for you:
      When it comes to omega 6, keep in mind that omega 6 is one of the two essential fatty acids. What this means is that you have to have some omega 6s in your diet because your body can’t make it and your body needs it. In our modern society, some people have to worry about getting too much omega 6s because they consume vegetable oils and other junk foods. But in the context of a whole plant food diet, you don’t have to worry about 1/4 cup of nuts (Dr. Greger’s daily recommendation) when it comes to omega 6. In fact, I’ve recently replied to two people who have been worried about getting enough omega 6 in their diet if they decide not to include nuts.
      In short, these “anti-nutrients” in nuts that you are talking about are a concern drummed up by the atkins/paleo/anti-science crowd. As NutritionFacts shows, the science supports a certain amount of nuts (perhaps 1/4 cup whole nuts or 2 tablespoons of nut butter) a day as being very health promoting.

  • I’d like to know if a person should limit their consumption of whole unfermented black olives? What is the maximum amount of canned black olives a person can eat every day and still stay healthy without any negative effects from eating the olives? Thanks.