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NBSV 144


Transcript of the No-Bullsh!t Vegan podcast, episode 144

Dr. Matthew Nagra on oils: how research was misinterpreted, and what it really shows

Karina Inkster: You're listening to The No-Bullsh!t Vegan Podcast, episode 144. Dr. Matthew Nagra is on the show to discuss one of the biggest myths within the vegan world, that all oils are harmful to our health. Not all oils are equal. A lot of research has been misinterpreted and there's a lot of research showing certain types of oil are, in fact, good for us. Let's get into it.

Hey, welcome to the show. I'm Karina your go-to No-B.S. vegan fitness and nutrition coach. If you're looking for a cost-effective way to level up your fitness with the help of two awesome vegan coaches, my team and I have a group coaching program you can join right now. We provide workouts and accountability as well as ongoing communication and a plant-based cooking and nutrition group. Head to to learn more and join us.

I'm excited to have Dr. Matthew Nagra on the show today. He's a naturopathic doctor devoted to bringing the most evidence-based nutrition information to both the public and his patients at his clinic in Vancouver. In 2018, he graduated from the Bouchet Institute after completing his Bachelor's of Science in microbiology at the University of Victoria. He is also certified in plant-based nutrition through eCornell and the T. Colin Campbell Center for Nutrition Studies and was a contributing author on professional health systems' nutrition textbook. He's also a public speaker and often tackles misinformation around diet and dives deep into the latest nutrition research on social media. Here's our discussion.

Hey Matt, thank you so much for speaking with me today and coming on the show.

Dr. Matthew Nagra: No problem. Thanks for having me on. I've definitely listened to a few episodes, so looking forward to It.

Karina Inkster: Oh, that's awesome. Well, I feel like I've been creeping on you online for a long time and all the work you've been doing, so I'm super happy we can connect finally.

Dr. Matthew Nagra: Oh yeah, no, me too.

Karina Inkster: Awesome. Well, we've got two main topics we're going to talk about. Also, there's an exciting new study that you just mentioned to me right before we hit record that I would love to go over. But, let's jump into your vegan backstory. So how and when did you come to veganism?

Dr. Matthew Nagra: Yeah, so when I was younger, I had some health issues. I struggled with my weight. I had asthma that at some points got pretty serious. I had, I mean, seasonal allergies, those things as well. And when I was about 14, 15, I was working with a personal trainer. I played a lot of sports throughout my youth, soccer being one of the main ones, but I was playing football as well at the time, American-style football. Just clarifying in case there's anyone overseas listening. So I was working with a trainer for that, and he really promoted a much more plant-based diet, not strictly but predominantly lots of heavy fruit and veggie smoothies, that stuff. He was very against dairy consumption, being one of the big things that he wasn't a fan of. And so I was supposed to fill out a diet diary just to record everything that I ate for a couple weeks.

And my diet was terrible at the time. A lot of McDonald's, stuff that I would make myself would be mac and cheese or just really simple things. And I didn't want him to see all that and then maybe work me extra hard in the gym because it was already hard enough. So I thought, you know what? I'm just going to try to take some of his advice for these couple weeks and change up my diet a bit. And so at that point, I got rid of a lot of the ultra-processed foods in my diet. I was having a lot more of fruits, veggies, I mean smoothies in the morning, that thing. A lot more salads and then still having a little bit of meat. I cut out the dairy at that point as well.

And I started feeling better. I was losing weight. My skin seemed to be clearing up. I was even breathing easier, and I know there's a little bit of data around fruit and veggie consumption and asthma as well. So I thought maybe that's playing a role. And so I thought, Hey, maybe he's onto something. Maybe this is not just all smoke mirrors and maybe diet actually does play a role. So I slowly started incorporating more and more learning, more and more about plant-based diets. And he did push me towards the raw food side at first, which I did get into a bit. And two years later, when I was at university, I noticed that my diet was sliding the other way again. I was eating a lot of cafeteria food, maybe not feeling as well, as vibrant as I was.

And so in my second semester, just one day I just was sitting in the cafeteria and I thought, you know what? I'm going 100%. I knew I felt better. So it wasn't so much the ethical side at that point - that did come shortly thereafter. But at that point, I just thought it's so much easier for me to stick 100%. I felt so much better when I was eating much closer to that, that I'm just going to do it overnight. And today is actually the 12-year anniversary of that date when we're recording this.

Karina Inkster: No way. how cool is that? Well, happy vegan anniversary.

Dr. Matthew Nagra: Yeah. So been 12 years strong ever since. And like I said at the beginning, it was more in the raw food realm and then obviously transitioned out of that later on as I became more familiar with the evidence and realized what, you can have things like rice and beans and et cetera, and you're really, really healthy. In fact, they're really good for you. So yeah. Yeah, that's the short version anyway.

Karina Inkster: Wow, very cool. It's really interesting to see how folks come to it and then how it expands over time. The motivations, the reasoning, why we stay vegan, it changes over the years and for me it was entirely ethical reasons, and now it's more health and environment as well. So I think that's a pretty common theme. One thing gets us in the door, so to speak, and then things expand over time.

Dr. Matthew Nagra: Yeah. And at this point, I wouldn't say that a vegan diet is necessarily more healthy than an omnivorous diet or that is necessarily the best healthiest diet. I think it is similarly healthy to a lot of the very healthy dietary patterns out there like Mediterranean Dash, et cetera, all very plant-heavy. But the reason I stick to 100%, and the reason I think a lot of people stick to 100% is because of the ethical side and just, you don't need to contribute to that, then why would you?

Karina Inkster: 100%. I just had a conversation with another evidence-based professional and he said something very similar based on the current research. There might be things around certain types of animal products, like you mentioned dairy, the red meat discussion is one thing as well, but depends what we're comparing it to. We can't really say across the board that any vegan diet is going to be better than any diet that includes animal products. But you're absolutely right. The folks that I know who have ethics somewhere in the mix are usually the ones who stay vegan long-term. Longer than, "Oh, it's just a weight loss thing.” Or, “I'm doing it just for the environment,” or a more one-sided approach.

Dr. Matthew Nagra: Absolutely agree.

Karina Inkster: Yeah. Okay. So I got to ask you this because there's a lot of listeners who at this point are like, dude, what's the deal with having a naturopath on the show? Now I know because I know your work. But other than being engaged with your content online and seeing what you do, my own experience with a naturopath has been homeopathy, which I know is not evidence-based. Now I know that's not the only method that's involved. But I would love to hear an overview of how you approach your work, because I know you're an evidence-based professional and there's probably a lot of bullshit busting that you have to do on a daily basis, I'm guessing, here around your profession. So I'm interested to see how you approach what you do from an evidence-based perspective.

Dr. Matthew Nagra: Yeah, I mean, just to start, I think one thing I've noticed a lot more recently is, especially in the newer generation of NDs coming out of school or even entering into school, is that there tends to be a shift towards much more of an evidence-based approach. I mean, we were even heavily involved, myself especially, in the COVID immunization campaign in Vancouver. Thousands of people, myself being involved there, and I worked with a lot of others who are involved too. So there are the two sides you could say. We also do learn a lot about pharmaceuticals we can prescribe here in BC as well. So it's not this anti-medicine profession, but as you said, there are modalities within the profession that certainly aren't evidence-based, and things that I wouldn't practice like, obviously homeopathy being one of the big ones. So in my practice, how I really approach it is, if possible, and if indicated, I do tend to focus a lot on nutrition.

I don't solely do that, but I get a lot of patients with say, cardiovascular risk factors, perhaps pre-diabetes, type two diabetes, where they might come to me actually looking for a non-pharmaceutical approach. I'll say, "Hey, you know what best outcomes we see typically with both, but if you want to first start, see how far you can get with the dietary approach, let's do that." And so we'll do that for a few months or so, see where numbers get, if they're happy with it, then great. If not, then maybe I'll be like, look, this is where your risk is at now. I'll calculate out, say their lifetime cardiovascular risk. Let's say if we put you on a statin at a given dose, this is where your risk will be. And then we can make that decision. And ultimately I'd say four out of five times they end up going for it.

Whereas if they had maybe seen someone else, or even if they had worked with their GP a lot of the time, just because they don't necessarily have the same amount of time to spend with them and to go over their concerns, they might not do that. And so that's I think one of the really cool things I've found about my practice is, I've had a lot of people end up probably doing what's best for their health because I've had that time to really dive into their concerns and explain the risks and benefits of the different approaches and giving them that opportunity to try the dietary approach first, where obviously I can counsel them on that as well. So if I had to give a general overview, that's the main part. I also do a lot of physical therapies for injuries and things, but that's obviously a bit separate.

Karina Inkster: Right. Yes, of course. Do you get a lot of folks who just slot you into a certain box because you're an ND and they don't realize that you're keeping up with the research and what you're doing is actually evidence-based?

Dr. Matthew Nagra: Oh, yeah. No. I get a lot of patients coming to me asking about, "Can we try this, or my LDL cholesterol is like 5.0, but I really want to avoid medications." And I'll just be like, look, that's very unlikely to be suitable in your case. Or in the cases of some therapies that maybe I don't practice or that aren't very evidence-based, just say, "Look, there isn't really evidence behind that, if that's what you want to work on. I'm happy to do these other things with you, but I'm probably not the best practitioner for that." And I actually do free meet and greet appointments, just, hey, have a 10, 15 minute chat with me first to see if it's a good fit. And if it's not, it's not. But yeah, I'm just not going to go treating someone in a way that I think is really useless or perhaps taking them away from more effective therapies.

Karina Inkster: Absolutely. Yeah, that's a good approach. Do you find yourself doing a lot of, I'll call it education around what is peer-reviewed? I mean, this is what you're doing online a lot of the times, but are you doing this on a one-on-one basis with patients as well? Someone might come in with a certain idea about what's going to work and then you have to maybe change their perspectives about things?

Dr. Matthew Nagra: I would say I do that a fair bit. It really depends on the patients. Some just don't care about those details, of course. But there are a lot of patients who really want to see the specifics. And I've got my Google Drive with all my research in there that I saved. It's almost full, actually. I got to expand it at this point. But yeah, I'll pull open the studies, I'll show them the charts, I'll explain what's going on. And I think one of the big things that really helps me in explaining, say the risks and benefits of different therapies is I'll just ask them, what are your concerns? So if I ask them, what are your specific concerns? Again, I'll go with the statin example because it's just so common. I'll say, "What are your concerns?" They'll say, "Oh, I've heard it damages your liver. I've heard it increases your diabetes risk. I've heard these things."

And I'll say, well, this is what the data actually says around diabetes. Maybe at high doses with very specific types of statins, there might be a slight increase in risk, but then there's still an overall benefit for cardiovascular risk. And I'll be able to show the numbers for those sorts of things. So definitely do dive into it. I explained some of the issues with maybe some of the evidence that they had seen. Maybe it is anecdotal or something that isn't necessarily high-quality, peer-reviewed literature. But also I would say that just because something's peer-reviewed doesn't necessarily mean it's great either. There are definitely some issues out there and a lot of the peer-reviewed literature every now and then. So it's almost frustrating that you have to really dive in almost regardless.

Karina Inkster: Well, I think it's great work you're doing. I think the education piece is missing a lot because, as our education system stands right now, you basically need to do a grad degree. I got to grad school before I learned how to do proper lit reviews and critiquing research. So this isn't something that's just taught in high school, which is crazy to me. I think that's got to change, but before it does, professionals like yourself are out there educating the masses online with content, but also in a one-on-one patient-to-doctor situation, which I think is super important.

Dr. Matthew Nagra: And I think it takes a lot of time to get good at this. And obviously, I'm still learning every day too, but to get good at actually evaluating research. The amount of time you have to put in your own life outside of even formal education is incredible. It's a full-time job really.

Karina Inkster: Mm-hmm. I can imagine. So tell me about this new study that came out. We're going to talk about this a little bit because we've got a large topic to dive into: everyone's favourite oil topic in the vegan world. But just before we hit record, you mentioned that there was a new study that came out and apparently it was really well done, and I'm very interested to hear about what they were researching and what the outcome was.

Dr. Matthew Nagra: Yeah, so actually before that study, I'll just mention that back in 2021, there was a great study published looking at vegan diets and omnivorous diets for muscle and strength gains. And this was done in Brazil where they enrolled, I believe it was 19 vegans and 19 meat eaters. They had them up their protein intake to 1.6 grams of protein per kilogram of body weight, which is the threshold for where we don't really see further benefit as far as strength athletes go. And they had them trained twice a week for 12 weeks, and at the end they ended up with similar muscle and strength gains and in every metric that they looked at. And so that's a really solid piece of evidence suggesting that you can do just as well or very similarly on plant protein as you could on animal protein or a plant-based diet versus an omnivorous diet.

Now this one, I think covers a few potential issues with that past one. For one, they hadn't trained in the original studies; they were untrained athletes. And a lot of people will point to the new gains or the fact that they weren't training, maybe they just did better or they would've done well regardless of protein intake. So that's one issue. The other one is training volume. So they only trained two times a week in that trial. In this new one, they trained five times a week. So what they did was, and oh, I should mention in that previous one, it wasn't randomized, which is a benefit because they wanted people who were habitual vegans. So they were eating a vegan diet for a while versus changing an omnivore’s diet or half the omnivores’ diets to a vegan diet where there could be other confounders like under-eating and things.

But in this more recent trial, they enrolled, in the first phase - there were two phases - in the first phase, they enrolled 16 people, mostly omnivores. There was one vegan. So that one vegan was placed in the vegan group, and the other 15 were randomized to either the vegan or the omnivorous group. They had them up their protein intake aiming for 1.8 grams of protein per kilogram of body weight, a little bit above that 1.6, mostly as a safety net, just to make sure nobody dropped below the 1.6 if they undershot a little bit. Now in the vegan group, a lot of the protein came from mycoprotein, actually. So it's a common protein source in  Quorn products. I don't think we really have them here, but in the UK they're very popular as well as you can get supplements with them. So they supplement it as well.

And in the Omnivorous group, they supplemented with milk protein to up their protein intake. And then they did that for three days and they measured what's called muscle protein synthesis. So this is sort of a measure of muscle-building activity, the incorporation of amino acids into muscle tissue. And there were no significant differences in their daily muscle protein synthesis rates, which is really cool because there are studies showing differences between animal and plant protein sources, but they're usually looking at very short periods, not overall daily muscle protein synthesis rates. And that mycoprotein tends to be really good at stimulating NPS as well.

And then they did phase two. So a few people dropped out of the study, so they enrolled some more and they upped it to 22 people, again, splitting them into the vegan and omnivorous groups. And they had them eat or aim for two grams per kilogram protein, again, as an added safety, I think a few people dropped a little below in the first phase. Just to make sure everyone was above 1.6, which they actually, everyone was above 1.8 even when they used the two kilogram per kilogram mark.

And they had them do that for 10 weeks and they resistance-trained five times a week. So a very heavy load there as far as training volume. And after that 10 weeks, there were no significant differences in lean mass gains. Both groups gained lean mass. No significant differences in muscle volume or muscle fibre size, cross-sectional area. And then when you look at the strength games, there were similar increases in, I believe it was squat, deadlift, and knee extensor strength. But there's actually a slightly bigger increase in incline bench press strength in the vegan group compared to the omnivorous group. But that seems to be driven by one outlier.

So there was one outlier who had a crazy game, and so if you remove them, it probably wasn't statistically significant. But just speaking overall, very similar gains across the board. No significant differences. If anything, the edge was given to the vegan group probably as far as size and strength gains, although they weren't significant differences. And they actually, to maximize those improvements, they supplemented both groups with creatine. I forgot to mention that earlier as well, just to get the biggest gains they could. And so this is just another piece of evidence, really well-designed trial where you actually achieve very high protein intake as well in both groups using high quality sources. We don't see a difference. Or at least not a significant difference. So, I think this whole argument, I mean, it's never-ending. There's always going to be complaints about some little details here or there, but at this point, I would say the onus is on people suggesting there's a difference to show that. Because the data's quite consistent, at least amongst the studies that we have.

Karina Inkster: Well put. Well, thank you for that summary. This puts, well, it doesn't actually, because as you said, these things are going to be rolling around forever. All these myths based on the other research that's already out there, be a pretty convincing piece of evidence to show that really it doesn't matter where your protein is coming from. But what I'm wondering is there's the folks in the vegan world who want the opposite. They want the vegan outcome to be better, and they're using veganism as a performance enhancer supposedly. Now, from what I've seen, there's not a ton of research on the vegan diet, whether it's for endurance athletics or for strength gains actually being superior. Now, I could be wrong, there's various theories about antioxidant levels and not consuming animal products, which might be pro-inflammatory. But what's your take on the state of research right now on the potential advantage of a plant-based diet?

Dr. Matthew Nagra: So I mean, I think the key is that there at least doesn't seem to be a detriment. That's the takeaway for me.

Karina Inkster: For sure.

Dr. Matthew Nagra: So there's some evidence, there's actually a couple studies. So this has been repeated, particularly in women, if I recall, where there might be better endurance performance, slightly not massive, not earth-shattering. And based on the type of studies, I wouldn't say we can really say too much about cause and effect. They tend to be cross-sectional studies. So just looking at a snapshot in time. You don't know if there are other, perhaps differences in the training protocols and stuff. I mean, you have a little bit of information about that, but not maybe a ton in most of these studies. So I would say it's at least as good, possibly better. I wouldn't say that we can make strong claims about it being better for those endurance outcomes, although the data we have suggests the possibility.

Karina Inkster: That's a good way of putting it. And again, we also need to take individuals into account. There are individual athletes out there who noticed a difference for themselves, which could be due to any number of variables of course, but we got to take that into account. But I appreciate the overall, here's the state of the literature at this point.

Dr. Matthew Nagra: Yeah, yeah.

Karina Inkster: State of the union. So let's get into one of our main topics. Probably the main topic, and to me this almost seems like the protein discussion because it just comes up over and over again. And you yourself have talked about this on multiple podcasts. You're probably so tired of it by now. And we are doing at least a two-part discussion with a heart disease researcher who's coming on the show later on to talk about this as well. So we're getting different perspectives about this oil topic that just won't go away in the vegan world. So there's a movement within veganism for those folks who are new listeners or who are new vegans, who have been vegan for less than four minutes and haven't heard about this, there's a movement for absolutely no oil. So there's a lot of high-profile cardiologists and doctors, I won't name names at this point, who are 100% against any oil in the diet, here's the kicker, for everyone in the population. So regardless of risk factors, current health status, chronic disease status, they're like 100% no oil for everyone.

And from what I understand, and I'd love to get your input here, that's not really a good fit with where the research is at this point. It doesn't take any context into account. It doesn't take the type of oil into account, but it's so prevalent. I mean, listeners who have been listening to the past few episodes probably know who I'm talking about when I say I had a conversation about something completely different. And this oil discussion just popped out of nowhere where the guest was like, "Nope, no oil for anyone. Never. It's just a bad idea." So we didn't really get into it because that wasn't the topic, but it pops up everywhere. And I would love to deep dive into this. So, let's start where you want to start. I'm opening the door on the oil discussion.

Dr. Matthew Nagra: I mean, on the plus side, maybe this is my bias perspective. I feel like I've seen a shift away from it a bit. So I'm hoping that that's the trend. But yeah, it does definitely pop up, especially amongst people who have followed a lot of the bigger name, plant-based docs and dieticians and whatnot for quite a period of time. And, I mean, it really comes back to a couple things. So the concerns around oils tend to stem from, there's like the study done back in, I think it was 80s or 90s, where basically they fed very large amounts of oil. It wasn't even like extra virgin olive oil. It was a refined version of olive oil, I believe, with bread actually - it wasn't even the oil itself - to participants. They measured flow-mediated dilation. So what they did is they put on a blood pressure cuff, pumped it up, I think left it on for five minutes or something, a really long time.

And then you release it and you see how well the artery can dilate again or essentially open up and let blood flow through. And they saw that it was impaired. The ability to do so was impaired after the oil and the bread and whatnot. And from this, there's this kind of speculation that that leads to poorer cardiovascular outcomes. The thing is these postprandial or post-meal, which means changes in flow media dilation, have never actually been shown to translate into outcomes or actual risk of cardiovascular events. That's what matters. And when we look at research on oil consumption, whether we have some randomized control trials as well, but especially if you look at the observational research nurses, health study, health professionals follow-up study, these are studies comprising a total of over 100,000 health professionals in the US who at this point have been followed for like 35 years or so. And you have really detailed information around their diet and lifestyle as well in those cohorts. So it helps to control for possible confounders.

And you see that things like olive oil and even vegetable oils tend to be quite health-promoting. If we look at meta-analysis of observational studies on vegetable oils like canola oil, et cetera, or olive oil, they tend to be associated with a lower risk of cardiovascular disease. And this is just very, very consistent. Now, what some others will do is they'll point to the case series by Dr. Caldwell Esselstyn or the randomized control trial by Dr. Dean Ornish, where in Dr. Esselstyn's example, basically took 198 people, put them on a very low-fat plant-based diet, no oil, and followed them for a period of time. Some people fell off the program, it was about 23, I'm going off memory here, but around 20 some odd participants fell off the program.

And those who stuck with the program had a very low recurrence of a cardiovascular event as these are people who had previously had a cardiovascular event. There's so much going on there. For example, you have highly compliant people with a very restrictive diet, probably also really good at taking care of their health in other ways. You have a very healthy diet overall, whether it has oil or not. So how can you point to the lack of oil being the main factor? And you're actually comparing to a group who weren't compliant. So there could be a lot of other differences between that, between the two groups. So that's one. With Dr. Ornish's lifestyle heart trial, they enrolled participants with coronary artery disease and they randomized them to either a control group who underwent standard care or an intervention, whereas a low-fat vegetarian diet where they were allowed to have egg whites and I believe one cup of low-fat dairy a day.

And then they also attended social groups, they took a vitamin B 12 supplement, they were told to stop smoking, but only one of them even smoked to begin with, so it's probably not a big factor. And then they mostly walked for exercise. And at the five-year follow-up, I mean, I think the control group had a two-and-a-half times greater risk of having a cardiovascular event. So again, significant reduction, a lot more going on than just oil or no oil. It's hard to pinpoint the oil factor there alone when we have all this data that adjusts for all of these other dietary variables, yet still finds that oil consumption is associated with benefits.

But one of the studies, I think, or one of the papers that really showcases the potential benefit of oils, especially polyunsaturated fat-rich oil, so these would be the canola, sunflower, safflower, et cetera, Is a substitution analysis where they looked at what would happen, or they modelled what would happen if you were to replace monounsaturated fats, polyunsaturated fats, or carbohydrates from whole grains, which again, healthy carb source with saturated fat and cardiovascular risk. And replacing saturated fat with polyunsaturated fats actually led to a greater reduction in risk than replacing saturated fat with carbohydrates from whole grains.

So suggesting that whole grain carbohydrates are better than say these polyunsaturated fats, which in those studies were predominantly from oils or nuts and seeds, though, those would be the main sources. It's just not supported by the evidence. And the evidence it tends to actually suggest that polyunsaturated fats are probably one of the better macronutrients for you. And those oils are one of the main sources. And same thing, if we looked at studies on changes in LDL cholesterol levels, which is a major risk factor for cardiovascular disease, canola oil tends to be the best oil out there for that, better than certainly carb sources and even better than olive oil and certainly better than the animal fats. So, it's very consistent in the data. I would say that these oils are, if anything beneficial. People don't need to have them though; you can get these polyunsaturated fats from nuts and seeds as well. But I think going on this super low-fat route actually does yourself a disservice in the long run because you're missing out on some of those benefits.

Karina Inkster: Absolutely. Well said. Okay. So let's unpack a couple of these points. So some things that are in my brain right now are, what you mentioned around the context piece, or does this actually matter? So the trial with the blood pressure cuff basically tested oil by itself because another issue is, which variable is actually causing the effect? So even in a study that's looking at just oil as a variable, the results don't necessarily mean anything. They don't necessarily mean that you're at an increased risk of negative health events. I think this is a big thing in research in general.

Dr. Matthew Nagra: Exactly.

Karina Inkster: You could have, I think there was a study at some point that found some food source quote, “doubled your risk for prostate cancer,” and it went from a background risk of 1% to a risk of 2%. So in the scheme of things, sure, technically it doubled your risk, but what does that mean in real life? So there's some interpretation there and there's some context.

Dr. Matthew Nagra: And one thing I often point to when it comes to the issue with say, extrapolating from this acute marker or possible mechanism in the flow media dilation is like if you look at exercise, moderate to vigorous intensity exercise can actually increase your inflammation. So imagine using that to suggest that it's bad for you because inflammation's associated with all these other diseases. But no, they're different. You're talking about systemic inflammation, that's chronic. And I mean that acute response could actually be a part of repairing damage or muscle tissue damage and whatnot, that is a good thing. And obviously when we look at the long-term data, which is almost exclusively observational for people who want to criticize observational research on exercise, it's clearly beneficial in the long run. There might be a point at which you're overdoing it so much that it becomes harmful. But that's at very, very, very high levels of exercise. And even that, I mean, there's a little bit of debate around.

Karina Inkster: Hey, that's a great analogy. It's causing this effect, which across the board is negative, so it must be negative with no regards to context. That's a really good point. The other point was about variables. So the studies that you mentioned, Esselstyn and Ornish, for example, involve so many variables that you can't be sure it was just the oil that caused the result.

Dr. Matthew Nagra: Absolutely.

Karina Inkster: So do you think these investigators, these doctors, these researchers are misinterpreting their results? I mean, they're still touting 100% no oil for the entire population.

Dr. Matthew Nagra: Yeah, I have no idea to be honest. Which the other thing I'll mention is it's weird to extrapolate that to the whole population. Because in Esselstyn's study that was secondary prevention, so people who've had a heart attack, let's say. And in the Ornish study, those are people with confirmed coronary artery disease. They might not have had an event already, but they were on their way at some point. And so these aren't necessarily the general healthy population. And then what about people like growing kids or athletes who have a tough time getting enough calories from just strictly plant-based diets without adding in some refined sources or processed sources like the oils? I think it's actually possibly a reason some people fail is because they're trying to adhere to this super, super strict, more limited diet where they're probably undereating and then they don't feel great and they fall off.

And so if it makes it easier for them to adhere, then go for it. I mean, look at the Seventh-Day Adventist population, one of the healthiest populations in the world. They're known for eating mock meats. It's one of the inherent parts of their diet, has been for a very long time. I believe that was introduced in the twenties or thirties and has been a mainstay since the fifties or something. It's going way back. And if incorporating some of those things, not like crazy, of course not every meal, but incorporating, whether it's oils or even some of these more processed meat alternatives helps people stick with it long term, provides a calorie-dense or more calorie-dense option, also more protein rich in the form of the meat alternatives, then I don't see a problem.

Karina Inkster: I'm 100% with you. And using myself as an example, when I worked in gyms with clients in person before I went online, so that's what I did for seven years. I was trying to hit about 3,300 calories a day just to maintain. This is not gain mode. This is just stay at normal mode. That is a shit ton of food, if you're eating no oil, only whole foods, I mean it's a ton of food anyways. But then you add on top of that, being allergic to all tree nuts and avocados, where the hell am I going to get my healthy fats from? So just using N equals one, there are lots of cases where these super restrictive, you're doing vegan wrong if you're eating oil, just doesn't apply.

Dr. Matthew Nagra: Yeah, no, I agree. It's unfortunate. But like I said, I do think, at least in my circles, I'm seeing a move away from that. But maybe it's just because people who follow me tend to not buy into that as much. I don't know. But I do tend to see a move away or shift away, which is great.

Karina Inkster: Well that is good to hear because I'm still getting the, it's almost a moral failing to some people if you're not eating exclusively whole foods. There's an ongoing conversation right now with one of our clients about what is processed food? And this ingrained idea that anything processed is bad for you. And I'm going to use the example of soy curls from Butler brand. A lot of people just, automatically assume that those are super processed, they're mock meats, whatever. It's whole soybeans that are cooked and extruded and dried. That's literally it. And if you think about what happens to oats, which everyone eats who is whole foods, it's basically the exact same process. They're cooked, they're flattened, they're dried, it's the same shit. But for some reason one of them is seen as super processed and the other one is a whole food. So there's no definition.

Dr. Matthew Nagra: And actually just talking about all the processed food and reminded me of another reason that people tend to talk negatively about oils. And that's just the fact that a lot of the ultra-processed foods out there, the very heavily salted fatty, sugary foods, they tend to have a lot of vegetable oils. That's one of the main fat sources because it is cheap. It's cheap, widely available, and tends to be in there. And so people will use that to suggest that the oils are the villain in that when really it's just the fact that they're hyper-palatable and people will overeat them and there's maybe other things that aren't so healthy. And actually another comparison I use there, is that it would be like saying that water is unhealthy because it's the main ingredient in Coca-Cola.

Karina Inkster: Ooh, that's a good analogy.

Dr. Matthew Nagra: But obviously everyone knows that we need water. So it's a really easy analogy to grasp. But yeah, it's sort of an innocent bystander there. Or I shouldn't even say innocent bystander because it does add a lot of calorie density and one of the problems with those foods is the fact that they're so calorically dense and easy to overeat on. But it doesn't mean that in isolation it's going to be a problem if you're cooking with it or putting on your salads or whatever.

Karina Inkster: Well, I realize that in the world of nutrition and fitness, a lot of folks are legitimately working on weight loss or fat loss to be more specific. That's fine, but I think the assumption with a lot of these foods is that's the only goal that people have. So the fact that oil is calorie dense, so one of the arguments from this podcast guest that I was speaking with about oil is how calorie dense it is. And I'm like, "Yes. So what's the big deal?" You're not going to drink it from the bottle. And in the context of what? You always have to ask in the context of what? If you're on 3000 calories a day, you probably have quite a bit more room than if you're calorie restricted in changing your body composition mode and you're doing 1500 calories a day. So there's no context. And I find myself frustrated at the assumption that everyone at all times is in weight loss mode. And that's the only legitimate health goal that you can have.

Dr. Matthew Nagra: Yeah, no, I agree too. I mean I think it's an interesting one because there's a lot of different sides to that discussion. And I sit on, it's a risk factor, just excess body fat in general, a risk factor for lot of diseases. Given the prevalence, a lot of people could probably benefit from reducing their body fat percentage, but it's not the only thing that matters. And certainly when it comes to weight shaming and stuff like that's got to go. But yeah, no, I totally agree that it's very shortsighted to only point to that factor. Which is really funny in this case because a lot of studies on vegetable oils and weight gain haven't actually shown that it increases weight. And that's because the way they're used tend to be eat more very low-calorie foods like vegetables. If you're cooking vegetables or you're pouring it on a salad or something, your overall calorie density of that meal is probably really low. And so that's another factor contact that gets left out.

Karina Inkster: Hey, that's a really good point. I'm way more likely to eat a salad the size of my head if it has some oil-based dressing on it. Now I'm not talking about dumping it on there necessarily. But that's an interesting point for sure. See, context again.

Dr. Matthew Nagra: Yeah.

Karina Inkster: Interesting. So what about different types of oil? So we've mentioned olive oil, some of the other ones like safflower, canola, sunflower. There's seed oils, there's avocado oil, there's peanut oil, which is technically a legume. What's the go-to suggestion? A lot of people are into flax oil, which you can't cook with. There's hemp, there's all these different types that just get lumped together into one category of evil for whatever reason. So what's the deal?

Dr. Matthew Nagra: Well, so olive oil or extra virgin olive oil in particular. Very good data, very consistent data on that being health promoting. A part of it might be the higher monounsaturated fat content, relatively low on polyunsaturated fats, a bit of saturated fat, but overall tends to improve lipid profiles and improve cardiovascular outcomes. But some of the benefit might actually be coming from the polyphenols in there. So especially with extra virgin olive oil, there tend to be a lot more. And so that's one that would be near the top of my list as far as the better ones, if you were to choose. Not that I think any of these are necessarily bad, so to speak. When it comes to lipid profiles like cholesterol, canola oil's probably the best, at least out of the ones that you would cook with or typically cook with. So that's definitely up there.

Avocado oil, I haven't seen as much research on that and outcomes. I would expect it to be pretty similar to olive oil though, just given its makeup as far as its fatty acid content. So I think totally fine option to use as well. You're not going to hear me say that any of them are bad options, really, just generally speaking. I think they're all pretty good, but the ones that we have a lot of data on would probably be the extra virigin oil and canola oil being very high on the list. And then flax oil, like you mentioned, funny enough, there was a study published just last week or two weeks ago on phytoestrogen content. And I mean there are lignans in flax, and that's a form of phytoestrogen. And it's the first study I've seen actually looking at flaxseed or flax oil consumption and risk of mortality. So total risk of death during a given period.

And they found that those who consumed flax oil versus those who didn't consume it had a roughly 10 ish percent reduction of risk of mortality, give or take a percent, I can't recall the exact number. And it was the first I'd seen, and that was from, again, the nurses’ health and health professionals follow-up studies I mentioned earlier. So that's just a cool finding to throw in there as well. And definitely one thing that I like to do for smoothies and that, especially for kids where you're, again, trying to bump up the calories a little bit, you throw in a tablespoon of that or something and you've added over a hundred calories right there. And obviously some great omega-3 fatty acids and the alpha lipoic acids. So yeah, I think there are a lot of really good options, but I just put a couple at the top of my list.

Oh, I should mention coconut oil though. That's the one that at least as far as people wanting to watch their LDL cholesterol levels and perhaps being on the higher end there, that's one to limit because that can raise your LDL cholesterol levels given the high saturated fat content, particularly when compared to unsaturated fat rich oils like the others.

Karina Inkster: That's a great point. I feel like the coconut oil craze is also decreasing, like this whole no oil thing, hopefully. But it is an important point to include for sure. And the flax oil reminds me of my 900 calorie smoothies that I used to drink. Put that in there for sure.

Dr. Matthew Nagra: I think I still do that.

Karina Inkster: Yeah, I don't anymore because I don't walk around a gym for eight to 10 hours a day. I'm sitting on my ass all day now. I still train, obviously. But it makes a huge difference. Interesting. Okay, so are there any points in this oil discussion that we have missed? Any kind of important pieces to mention?

Dr. Matthew Nagra: I mean, I don't think there's any major issues that we'd missed out on. I mean, a lot of the stuff you'll see online, particularly around the polyunsaturated fats and the seed oil so to speak, is largely based on animal research. So they'll look at what happens to rodents or they'll look at specific markers like oxidized LBL or something like that, where I think it's just important for the audience to understand that the translation rates between that research, so research done on a specific marker and a Petri dish or on a animal model is very low to humans. It almost never actually works out that way in humans because our bodies are complex and they're obviously different than rodents. So just something to be aware of when you see these sorts of claims online. Just take a step back, say, are they looking at an actual outcome like risk of heart attack or stroke, or are they looking at some modification to a specific marker that occurs in, I don't know, a rat or something? Then maybe it's not super relevant. And so that would just be one little takeaway.

Karina Inkster: I think that's a great point. And if listeners want to go back to the very first episode of the No-Bullsh!t Vegan Podcast, I've got I think it's eight. It's been a while since I've listened to it, but I think there's eight questions to ask yourself when you're looking at research and things like compared to what are some of those questions. So the context that we've discussed today, the variables, potential confounding variables, all those things are in those eight questions. And it's part of the reason I started the podcast actually, is, what is the research legitimately saying right now? And let's bust some myths around some of these things that are not peer reviewed and not evidence-based. So what you're saying there reminded me for folks if they want to go back to episode one. But you have an online community and you have a free download. Can you tell us about those two things?

Dr. Matthew Nagra: Yeah, yeah. So the download, it was funny, I had, a lot of patients would come to me working on their cholesterol levels, as I've talked about quite a bit. And I used to use this handout from the University of Toronto. They actually have a really good handout on the portfolio diet. It's essentially a bunch of different foods or food groups that can help lower cholesterol levels. And so I used to give that, and then I just thought, there's some info missing and I feel like you could add this and that. So I just went ahead and did that basically and made my own, added some extra background information on that so people can download it for free. It's just on my website, And then I also have just this online community private Facebook group where we do weekly live discussions and obviously if people have questions and things, they can throw them in there and we chat back and forth. Also on my website, for that one.

And then obviously social media, that's where I do all my regular postings. So that study we just talked about earlier, the athlete one, I think I'm going to try to record that tomorrow and get it out as soon as possible. So it'll definitely be out by the time this airs. And then whatever else comes up, I've got a whole list of stuff I'm ready to post. I just need to write it up and record it so you can keep up with that there.

Karina Inkster: It's a lot of work. It's a lot of work. It's awesome work you're doing. Here's one last question for you, just on a personal curiosity level. Where are your go-to research sources? So Google Scholar,, some of those are on my list. What are yours? You probably have access to more things than the average person who isn't a doctor. But I'd be interested in your options.

Dr. Matthew Nagra: Yeah, so I mean obviously for clinical practice, I use just the medical guidelines a lot, whether it's Canadian Cardiovascular Society, or Up-To-Date is a really good one. But that aside, because I don't think that's what most people are going to be interested in, I actually primarily use PubMed. So I have, what's really cool about is you can make an account and you can set up searches. So I have predetermined or preset up searches for different topics, one on beverages, so that's all your tea, coffee, sodas, water, et cetera. I have one on just diseases, that's always the biggest one because it's just a list of diseases that anything that's published with those diseases comes up. I have one for plant-based diets. I have a few others. Anyway, and basically every day it just updates with whatever else is published and then I can filter through for the types of studies I'm interested in and go through them. And this morning I planned to get a bunch of stuff done and then that athlete one came out, or the one I was talking about.

Karina Inkster: You're like, well, my day is set now.

Dr. Matthew Nagra: Yeah, I know. I checked my email and I was like, is this going to be good or what's going on? And then I opened it and I just got drawn in. I spent an hour and a half going through it in detail. And then, so yeah. But that happens once in a while too. But yeah, so I really use PubMed primarily. And then I also just have people who I follow and just online communities I'm a part of where they tend to post stuff and if I happen to miss something doing my own searches, I always pick up on it in these other places. So that's just not something I can really advise someone on. It's just find sources that you enjoy or who post content that you enjoy, and then you'll see things pop up that maybe you wouldn't have seen otherwise. But yeah, PubMed's the go-to for me.

Karina Inkster: Love it. Love it. Well, you're one of those professionals who is providing this information for the rest of the world, so I appreciate your work. Great speaking with you. Thank you so much for coming on the show.

Dr. Matthew Nagra: Thanks for having me. It was good. And fun chat.

Karina Inkster: Thanks again for speaking with me, Matt. Great to connect and I so appreciate a good B.S busting session. Access our show where you can connect with Matt and you can download his free guide to optimal cholesterol levels. You can also sign up for his newsletter and his exclusive online community with weekly live discussions covering a variety of topics in more detail than what he posts on social media, which is already an incredible level of detail, so this is saying something for sure. Also, don't forget you can learn more about and sign up for my group fitness program at Thanks for tuning in.

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