More on Low-Fat Diets and an Update on Heart-Healthy Fats

My recent post on low-fat vegan diets inspired some good and thoughtful comments, which I really appreciate. Coincidently, just a few days after I posted, an important study was published that supported some of what I was saying. There are lots of studies to support the content of that post (I don’t make this stuff up; I swear) and the idea that eating some fat is good for you is hardly a new idea. But this was a particularly interesting bit of research coming just on the heels of the discussion here.

And so I wanted to talk about that study and also respond to some of the issues that were raised by my last post. Especially in regard to one comment which pointed out that the Ornish Program isn’t going to stop working just because new research has been published.

That’s true. I’m not saying that the Ornish Program doesn’t work. I’m saying that, based on what we know about fat and heart disease, it is probably not the best approach. And more importantly, the reasons why it works most likely have nothing to do with the low-fat aspect of the diet.

In fact, the Ornish study didn’t prove anything about low-fat vegan diets at all. Aside from the fact that the diet isn’t vegan, the program is a comprehensive lifestyle makeover and it’s not possible to determine which aspects of the program were responsible for the benefits. For one thing, as soon as you add exercise into the mix, it becomes really difficult to give diet much credit—because exercise is probably far more important for reducing disease risk than any dietary change you can make.

But even assuming that the benefits are all or mostly due to the diet used in the program, it doesn’t follow that you need to reduce all fats in order to reap those benefits. That’s because the various low-fat vegan diets that have been used to reverse heart disease have two important things in common: they are low in saturated fat and they produce weight loss. Both of these factors reduce heart disease. So if people in these studies are losing weight and eating less saturated fat, there is just no way we can say that it is the low total fat content of the diet that is responsible for their improved health. And, in fact, the research really does suggest otherwise.

The new study that was published last week was a meta-analysis of randomized clinical trials (RCTs). (Not all studies carry the same weight in scientific research but RCTs are considered to be the gold standard.) The researchers, who are well-respected Harvard scientists, found that simply replacing saturated fat with polyunsaturated fat reduced coronary heart events (like heart attacks) by 19%. (And a reduction in heart attacks is a much more meaningful outcome that a reverse in atherosclerosis.) Not only that, but for every 5% increase in unsaturated fat consumed (as a replacement for saturated fat), heart disease risk went down by 10%.

It’s fair to assume that people who also adopt a vegan diet (in addition to reducing saturated fat and increasing polyunsaturated fat) might have even better outcomes. Vegan diets have the added benefits of more fiber, antioxidants and other good things in plant foods. There is every reason to believe that a vegan diet based on whole plant foods, and including some good sources of unsaturated fat, is the best heart healthy way to eat.

In a study published last year by Dr. David Jenkins, a vegan diet rich in plant protein and fats (43%!) produced a better blood cholesterol profile than a diet high in complex carbohydrates and it was just as effective for weight loss. The subjects also found it more satisfying. These are just a couple of the studies that make the case that type of fat is more important than amount of fat in the diet for heart disease prevention. (This is true only up to a point of course and I am not recommending a 43% fat diet!)

So to summarize from this post and my previous one:

  • Replacing saturated fat with either carbohydrate or unsaturated fat will lower blood cholesterol. (This is not at all a controversial idea.)
  • Replacing saturated fat with unsaturated fat produces a better cholesterol profile than replacing it with carbohydrate. (Again, this is well-recognized, although experts debate about how much it matters in different population groups. For women, people with diabetes, and those who are overweight and/or sedentary, it probably matters a lot.)
  • Heart health benefits seen with very low-fat diets are largely attributable to weight loss and a lower saturated fat intake.
  • Fat intake should probably be moderate and definitely spread out through the day to avoid single high-fat meals.
  • Some high-fat foods like nuts and possibly soyfoods have specific heart-health benefits that have nothing to do with blood cholestrol levels.

The bottom line is that the current research suggests that very low-fat diets are not necessarily the best way to eat. Or at the very least, they are not the only good way to eat.

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25 Responses to More on Low-Fat Diets and an Update on Heart-Healthy Fats

  1. aveg April 1, 2010 at 7:16 am #

    "Replacing saturated fat with unsaturated fat produces a better cholesterol profile…".

    So true!

    However, what about the CANCER promoting effects of ALL added dietary fats that Dr. John McDougall has been reporting on for the past 26 years?

    A balanced whole plant food diet contains the fat profile designed by nature, that we require for good health. According to McDougall, adding fat, even unsaturated fat, increases cancer risk.

    I'm concerned this article may mislead people into believing refined fats are health foods when in reality they appear to act more like drugs with a nasty side effect – cancer.

  2. Ginny Messina April 1, 2010 at 8:17 am #

    Aveg, this is another situation where we need to move on from what we were saying 20 and 25 years ago and look at the more recent data. Based on the overall research on fat and cancer, the evidence of a relationship is actually pretty weak. If you don't believe me, check out the report from the American Institute for Cancer Research and the World Cancer Research Fund, which is an extensive in-depth and highly respected summary of the science on this issue.

    But even if it were true that a diet high in fat raised risk for cancer, it would be both simplistic and extremist to conclude that this means we need to avoid all fats. There are plenty of dietary components that are benign or even beneficial in moderation but bad for us in excess. For example, many vitamins and minerals are toxic at high levels. Sometimes, a moderate amount of something in the diet is actually better than too little or too much, and that seems to be the case with plant fats.

  3. beforewisdom April 1, 2010 at 3:39 pm #

    Heart health benefits seen with very low-fat diets are largely attributable to weight loss and a lower saturated fat intake.

    I was interested to read that.

    There is no shortage of personal blogs on the net about formerly obese low carb dieters claiming that their various health markers improved on their low carb diet.

    They use those test results to "prove" that low carb diets are healthy and "the natural diet" for all people.

    I wasn't sure until I read this article, but I had a vague memory of reading that any fat loss would improve some health markers……whether the means of fat loss was healthy or not.

    It is good to have this information confirmed as those blogs do influence other people to make under-informed choices.

  4. William Kruidenier April 3, 2010 at 6:27 am #

    Thanks for this info! I'm new to your blog, so don't know if you've covered this or not — but I'd like to read your thoughts on Dr. Esselstyn's avoidance of all oils for "preventing and reversing" heart disease. He notes that the Mediterranean Diet got lots of press for reducing heart disease vis-a-vis the use of e.v. olive oil, but that reducing is not as good as eliminating. He isn't against "fat," but against "oil" — fat removed from its whole food environment. He sees consuming oil as the equivalent of throwing gasoline on a fire with regard to endothelial damage in the arteries. Do you have thoughts on this? Thanks!

    • Robert January 25, 2011 at 1:01 am #

      Not true! Dr. Esselstyn is ineed anti-fat. Oil is only one source of fat he eliminates from his diet. He is also against nuts and avocados because of their fat content, regardless of the type of fat they contain. 

  5. Susan April 3, 2010 at 10:25 am #

    Hi Ginny,

    Thank you for the helpful information.

    When we talk about replacing saturated fats, this includes saturated fats from plant sources, as well as animals, yes? I'm referring to products made from coconut milk. I've been told this fat is "healthful," but am skeptical.

    This is from Turtle Mountain's website:

    "Although coconut contains saturated fat, a closer examination shows that not all saturated fats pose a health problem. Saturated fat chains exist in a variety of lengths which impact the body differently.

    Research has demonstrated that Long Chain Triglycerides (LCT) represent the most sinister saturated fat. LCTs exist primarily in foods derived from animals and have been linked to heart disease and a number of other chronic conditions. The body stores LCTs as fat. Americans consume an excess amount of animal-sourced LCT, which drives many of the health problems in this country.

    Coconut represents a vegetarian-sourced saturated fat consisting of medium chain fatty acids (MCFA). Scientists have long recognized MCFAs such as lauric and capric acid for their anti-viral and anti-microbial properties. The body utilizes MCFAs as energy instead of storing them as fat."

    My default response has been to avoid coconut milk generally, but I have not been able to find a reliable answer to this question. Are all saturated fats bad?

    Many thanks!
    Sue

  6. Elaine Vigneault April 3, 2010 at 1:36 pm #

    On the other post you said in the comments "My point is that there is absolutely no reason to eliminate all fatty foods from a vegan diet." [...] "as vegan advocates, we want to promote a healthy diet that is actually attractive to people."

    As a vegan advocate, I'm far more interested in saving animals' lives than in promoting a low fat diet. So, I'm not about to tell someone to stop eating a fatty food so long as that food is vegan. Quite honestly, I don't know any serious vegan advocate who does this. You seem to be fighting a paper tiger.

    I see some vegan advocates encouraging a low-fat vegan diet, not a diet void of all fat. But the other thing I see is this: average nonvegan people going out of their way to try to get something they think is "good fat."

    I see fish oil (one of the so-called "good fats") now being added to all kinds of foods that used to be vegan!

    Because of this omega 3 craze, average people are eating ridiculously high quantities of fatty foods… THAT AREN'T EVEN VEGAN.
    Or they're taking fish oil supplements!

    I'm wary about jumping on a fat bandwagon because it seems like it's just another wacky nutrition trend. From my perspective, the general result of fat consumption promotion is a) total caloric increase and thus weight gain and b) promotion of nonvegan foods.

    This does not seem to me to be a truly effective way to promote a healthy vegan diet.

    • Lucas March 2, 2011 at 4:29 pm #

      I am a vegan and have been for 10 years, but something I would never do is take the life or welfare of an animal over my own health.  If a diet lower in fat is healthier for humans then adding in unlimited fats as long as they are "VEGAN", I would not promote the higher fat foods.

  7. Ginny Messina April 3, 2010 at 3:25 pm #

    BeforeWisdom, you’re right that weight reduction (if the loss is in body fat) will almost always improve some health outcomes. In particular, it will reduce cholesterol levels and usually hypertension. So as soon as people are losing weight in a study, it becomes difficult to attribute improved health to anything other than that. It doesn’t mean, of course that the diet isn’t having an effect; it just doesn’t provide any proof of that potential effect.

    William, I would agree that getting most fat from whole foods like nuts and avocados, and from traditional soyfoods, rather than from oils is by far the best approach. However, the Mediterranean diet, which is typically rich in olive oil, is associated with some good outcomes. In fact, in an analysis of the effects of diet on heart health that was published last year in the Archives of Internal Medicine, the only things that seemed protective against heart disease were vegetables, nuts, monounsaturated fats and a Mediterranean diet pattern. The study I noted in this blog post, though, didn’t find that protective effect for monounsaturated fats. And some researchers have suggested that the true benefits of olive oil might lie in the fact that vegetables cooked with it taste better and therefore people eat more vegetables.

    I think a diet that is high in oils is probably not good, but that doesn’t mean that we need to avoid oils 100%. As I noted in my post, something can be bad for us in large amounts, but still be benign—or even beneficial—in small amounts.

    Susan, it’s true that some saturated fats don’t raise blood cholesterol. Whether they have other negative effects on health isn’t so clear (Saturated fat might be harmful in other ways apart from its effects on cholesterol.) The evidence suggests that coconut oil is probably okay. I’d like to see some more research on this myself. I occasionally cook with it and I eat Coconut Bliss ice cream for a treat, but I don’t use tons of it. I’ll try to read up more on this and blog about it in the future. It’s an important question.

    Elaine, I write about vegan nutrition for vegans (or potential vegans). I am not making recommendations here for omnivores. And I’m not suggesting that all vegans need to go out of their way to add more fat to their diet. I am saying that there is no reason to go out of one’s way to eliminate all fatty foods from a vegan diet.

    There are, in fact, many advocates —among those who adopt a vegan diet for health reasons in particular—who suggest that all added fats and high-fat plant foods should be avoided. They advocate diets that are as low as 10% fat. I am suggesting that the scientific evidence does not support this way of eating. It is based on older data that has not held up well in view of more current findings.

    So, if it’s not better for us, why would any animal activist want to promote a way of eating that actually makes a vegan diet more difficult? That doesn’t seem like especially good activism to me.

  8. CamelMan April 5, 2010 at 2:34 am #

    I'm sorry but I feel I need to point out that this article is mostly spin.

    The Lifestyle Heart Trial reduced cardiac events 60%, i.e. three times better than the study you referred you. I suppose this must have been due to the exercise and meditation? Those must really be a miraculous combination then, especially if they also had to counteract the worse low-fat diet.

    JAMA. 1998 Dec 16;280(23):2001-7.
    Intensive lifestyle changes for reversal of coronary heart disease.

    Ornish D, Scherwitz LW, Billings JH, Brown SE, Gould KL, Merritt TA, Sparler S, Armstrong WT, Ports TA, Kirkeeide RL, Hogeboom C, Brand RJ.

    PMID: 9863851

  9. Ginny Messina April 6, 2010 at 1:05 pm #

    Peter, the study I cited looked only at the effects of replacing saturated fat with unsaturated fat. We wouldn’t expect that it would provide as much benefit as a program using a much lower intake of saturated fat, higher intake of antioxidants, more fiber, plus weight loss, exercise, etc. That’s why I noted in my post that one would expect effects to be much greater that what was seen in the Harvard study when we start adding in the other benefits of a vegan diet.

    My point in citing that study was that replacing saturated fat with unsaturated fat is as good, if not better, than replacing it with carbohydrate. In fact, as unsaturated fat intake went up in this study, risk for heart disease went down.

    Again, I am not saying that a vegan diet based on whole foods with a very low saturated fat intake is not beneficial for reducing heart disease. And I’m not saying that high fat diets are good. I’m saying that avoiding all fats—including healthful plant fats from nuts and seeds—is not necessary or beneficial for reducing risk. The benefits we see in studies like the Lifestyle Heart Trial come from some combination of factors—most likely the low intake of saturated fat, high fiber, weight loss and exercise. This is good news, don’t you think? Yes, it means letting go of some ideas about diet that haven’t held up to more current research findings. But it also means that we can tweak diets like those used in the Ornish plan in order to take advantage of their benefits while removing some of the barriers that keep people from embracing the ethical and health benefits of a vegan diet.

  10. Veronica persica April 7, 2010 at 3:01 pm #

    Great, unbiased summary of the most current data. Health and veganism are different, but being healthy vegans is important if we want to be able to continue being vegans.

  11. Elaine April 7, 2010 at 3:32 pm #

    This is a wonderful blog and so informative!

    There is SO much for the average person to take in, in terms of diet and health information!

    I try to stay relatively well-informed, but feel like I fail all the time.

    I'm eating, currently (past 10 months or so) an "almost vegan" diet — I do cook with olive oil, occasionally coconut oil and I eat *small* amounts of cheese about twice a week. Sometimes I cave and have one yogurt.

    :) My weakness has always been baked goods. I've started baking vegan stuff, but honestly — is it THAT much better for you than the original versions? I think it's still junk food — just without animal products!

    Elaine

  12. Ginny Messina April 7, 2010 at 5:50 pm #

    Veronica, I agree–doing what we can to stay healthy is important for our advocacy. We don't know exactly what type of diet is best, but have enough information to make pretty good choices for the most part.

    Elaine, would it make you feel any better to know that most nutritionists also find it just about impossible to stay well-informed? There is always something new to learn or something confusing to sort out.

    And, I think some vegan treats are better than others. A homemade apple crisp obviously has a lot more good stuff than brownies, for example. But you're right–generally, cookies, cakes, etc are not especially healthy, vegan or not. The real plus is that the vegan ones are cruelty-free. And if most of your diet is whole plant foods, I doubt that you will do yourself much harm with treats now and then. And congratulations on your transition to almost-vegan. You deserve those cookies!

  13. leo April 10, 2010 at 2:38 am #

    I'm concerned this article may mislead people into believing refined fats are health foods when in reality they appear to act more like drugs with a nasty side effect – cancer.
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  14. Ginny Messina April 10, 2010 at 8:22 am #

    Leo, that's a reasonable concern. I definitely don't want to give the impression that its okay to eat tons of refined fats. Mostly, I wanted to say that higher fat whole plant foods (like nuts) are perfectly okay to include in the diet and it's probably better to eat small amounts of these foods than not. And small amounts of refined fats are okay as well. Again, we need to get away from this "all or nothing" way of thinking about nutrition. The science doesn't support it. Something can be bad for you in huge doses but perfectly healthful in small ones.

  15. MaryJoCrazy April 13, 2010 at 11:51 pm #

    So happy to see vegans on here! :D I Love It!!!

  16. leslie April 20, 2010 at 9:23 am #

    Thanks for spreading the word. Eliminating fat from our diets is dangerous and unhealthy. We must make the right choices when it comes to fat and how much fat we consume. Choosing foods like almonds and avocados that are loaded with "good fats" is an excellent start.

    Dr. Josh Axe
    http://www.draxe.com

  17. Humanimal April 21, 2010 at 3:23 pm #

    Ginny,

    I'm so impressed with your work on this blog. You continually avoid the temptations of hyperbole and generalization in favor of truthful and professional reporting. You're a credit to all vegans.

  18. Shirls April 27, 2010 at 1:34 pm #

    I love your perspective, Ginny. You seem wise to me. Too much fear of food is being spread and I like that you are not trying to do that. Too many people are using their personal beliefs about food as a way to judge people and it is very unattractive. I have been vegan since 1984. I have reached some of the same conclusions that you have. A lot of diet dogma exists and misinformation is easily spread. A return to common sense is needed.

  19. C1 May 18, 2010 at 3:51 pm #

    Ginny,

    It strikes me that the Esselstyn work (mentioned previously) is perhaps more germane than the Ornish stuff. The Ornish program introduces a number of factors you mentioned (stress reduction, exercise, greater social interaction) whereas the Esselstyn program focuses solely on diet (and very heavily on fats (there are no expressed oils, but I believe it is also extremely low-fat as well). You speculated that weight loss and a reduction in saturated fat could explain the effect, but where is the data that shows reversal from those two factors?

    Also you state this: "And a reduction in heart attacks is a much more meaningful outcome that a reverse in atherosclerosis." Why is that? Isn't it more unlikely that you could actually reverse it? (I'm genuinely curious, I hope it is not coming across as though I'm challenging you on that)

    Thanks for all of the info and your work on this.

  20. Nancy August 13, 2010 at 1:02 pm #

    I am interested in making a change to vegan eating or health reasons but don’t know where to begin. Can I get help from anyone ou there on where to start?

  21. gxs December 30, 2010 at 3:32 pm #

    Very interesting discussion here. I myself have adhered to a very-low-fat,  low-glycemic-index vegan diet (practically no added oils, no nuts, no olives, no avocados, I even avoid soy) for nearly a year now. Motivation: marginal fasting sugar readings shortly before I got on this program (technically, "pre-diabetic"). 
    I subsequently researched the topic, came across Dr. Neal Barnard's recommendations, and decided to check out his findings for myself. I'm glad to report that at least for me: yes, his recommended diet for "reversing type 2 diabetes" does seem to work. My A1C went from 6.0 to 5.6 (before and after I got on the diet). I also saw dramatic improvements in my cholesterol readings, and in general find it effortless to keep weight off. One of the key attractions of the low-fat vegan regime is, one can pretty much eat unlimited quantities of the allowed foods (which I happen to like anyway – fresh fruit, vegetables, whole grains and beans) with little or no impact on the A1C. Dr. Barnard's hypothesis on this is, fat is the culprit relative to insulin resistance – not unrefined carbs. 
    Anyway thought I'd jump in and point out that some of us have specific reasons to stay low-fat. In my case the program is directly addressing my specific health concerns, and I don't forsee any problems with staying indefinitely within the bounds of the recommended foods. So from my POV, I see no reason at all to rock this boat.

  22. Lucas March 2, 2011 at 4:24 pm #

    What are your thoughts on the bodies limited ability to convert omega 3 fatty acids once the ratio of omega 3 to 6 goes higher than 1:4.  If this is true, you must be much more careful in your selection of nuts and seeds.  Most nuts and seeds are loaded with omega 6 and severly lacking in omega 3, with hemp, chia, and flax being the only exception with ratios favoring omega 3 over omega 6.
    Also, what do you consider a healthy percentage of total fat per day?

  23. Reggie April 2, 2012 at 9:23 am #

    Thank you very much for this clear concise article. You clarified many aspects of this controvercy for me.

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