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Vegan vs. Omnivore

This is a chronological breakdown of the Joe Rogan Experience #1175 - with Dr. Joel Kahn and Chris Kresser, debating on whether a whole foods based vegan diet or a whole foods based omnivore diet is better.  I’ll lay out their arguments and add a little commentary where relevant.

At the end I’ll briefly talk about what I think each side could have done better. First here’s a list of the topics we’ll look at: The discussion starts with introductions. Dr. Joel Kahn MD is a holistic cardiologist and 42 year vegan.

Chris Kresser has a Masters in Science and is the co-director of the California Center for Functional Medicine. He was once a vegan, but switched to a whole foods omnivore diet. Around the 6 minute mark, they jump into discussing the problems with using epidemiology to make conclusions about nutrition.

“Epidemiology, observational studies, are studies that look at a certain group of people… say we take a group and we look and see how much saturated fat are they eating - we separate them into, y’know, low consumption, medium consumption, high consumption… we might then look 20 years later and see how many people had heart attacks and died…” The criticisms mentioned were that .Epidemiology assumes that there is one diet for everyone.

It reduces everything down to components without looking at the whole picture. For example if a study is looking at the effects of high fat diets, it wouldn’t differentiate between a high fat dominoes pizza and snickers bar diet and a carefully formed whole foods diet that is packed with coconut oil and avocados.

Dr. Kahn does say that epidemiology studies are at least useful for testing hypotheses.  “You can test a hypothesis … what happens if … our data, may be crappy, but it’s still data and it allows you to go further with 100,000 people, 50,000 people, 500,000 people” Kresser then goes on to explain three more problems with epidemiology: “I think there’s huge problems with epidemiology.”

.The data are only as good as the tool used to collect them. The tool very commonly used for epidemiology studies is a questionnaire, which is not reliable simply because people are not good at precisely remembering what they ate.

An example of this problem is the recent study on low carb diets which relied on a questionnaire like this one asking participants things like “How many of these foods did you eat per month over the past year?” My hat is off to you if you can remember your precise monthly consumption of bananas, broccoli and chicken for all of last year.

The second point is the healthy user bias which says that people who are likely to do a vegetarian diet, which is thought to be healthy, are also likely to do several other things that are thought to be healthy like not smoke or get plenty of exercise.

“Well, red meat has been perceived as unhealthy for a long time. In those observational studies, the people who eat more red meat are also smoking more, they’re eating less fewer fruits and vegetables… they have higher body mass index, they’re less physically active. So how do you know that it’s the red meat… that’s causing the problem and not those other things? You don’t.”

The third point is that the relative risks in nutrition derived from epidemiology research are so low that they are indistinguishable from chance. “So, in fields outside of nutrition and epidemiology, nobody would consider an increase in risk less than %100 - a doubling, to be really worth paying attention to.

The observational studies that Joel was referring to that confirmed that cigarette smoking led to lung cancer… that showed between a 1000 and 3000 percent increase in lung cancer in smokers. Okay? The IARC, the WHO report that suggested that processed red meat is a carcinogen - that was 18 percent increase” “Lot of respect and agreement, but if we throw epidemiology out-“ “I’m not suggesting that by the way.”

“I know I know, if we throw epidemiology away, we’ve thrown away about 80% of nutrition knowledge, because that is the most common kind of study. And that still leaves us with basic science, it leaves us with randomized clinical trials which are very hard in nutrition, and they’re very expensive.

And it finally leaves us with studying old healthy people - centenarian studies.” Around the 34 minute mark, the conversation shifts to meat. Kresser mentions that the proposed mechanisms thought to be behind processed meat causing cancer are N-nitroso compounds, heme iron, TMAO and Neu5GC and heterocyclic amines formed from cooking.

He then points out that context is very important: For example, eating a hot dog is very different from eating a hotdog with Kale. vegetables reduce levels of N-nitroso compounds and heme iron, and cruciferous vegetables reduce heterocyclic amines. Neu5Gc wasn’t addressed but TMAO is discussed later in the debate.

Kahn agrees that if people eat meat it should be with vegetables. “Next time you eat meat, get a salad, next time you eat meat, order broccoli. Next time you have bacon, get a, y’know, sliced tomatoes. You will actually improve your health.” “they took healthy volunteers, they took them down to the hospital cafeteria and they fed them a hospital burger, and they were measuring on their arm how their arteries functioned.

Artery function goes down in 3 hours when you eat a hospital burger. They took the same group a week later, they had them eat the same burger with a big salad. They didn’t see that finding.” After this, from about the 40 minute mark and for the next hour and twenty minutes, they had a meandering discussion on whether saturated fat causes heart disease.

Dr. Kahn illustrates his position on saturated fat with five points, starting with some history: “…Ancel Keys suggested dietary fat might be a factor - it was a hypothesis, it was early stage epidemiology, doesn’t prove anything.

He went out and did studies, other people did studies and the idea transitioned, the focus went on saturated fat in food which is basically chicken, red meat, pizza and subsequently enough data accumulated that guidelines started to suggest - we have this huge problem with heart disease, we should limit saturated fat in the diet.

And that has now promulgated into 21 international statements, whether it’s the World Health Organization, American Heart Association, American College of Cardiology - Institute of medicine says eat as little saturated fat as possible - they couldn’t be more clear, and these are high brow.”

“Okay but why did they come to the conclusion that saturated fat-“ Then he explains that this is because .Basic science shows that when you eat foods rich in saturated fat - which is called: “meat, cheese, eggs and such”, receptors on your liver for cholesterol goes down.

This prevents the cholesterol from getting into the liver so the cholesterol floats around in the blood stream. “That’s the basic biochemistry. Then they had epidemiology studies, flawed, perfect, it doesn’t matter, there were so many of them.” “Then they did controlled trials - Clarke 1997, 395 - it’s called metabolic studies - change the diet, see what happens. You add saturated fat, cholesterol skyrockets - on average, not in a single person. Then there were many epidemiology studies that seemed to support this point.

.Then there was a 1997 paper on 395 metabolic ward experiments that showed that saturated fat increases cholesterol on average - not in a single person. …It’s our microbiome… it’s our genetics - it would rise.” “And then finally, finally, they looked at populations that live over 100 - these are called the pillars of longevity - they don’t eat foods rich in saturated fat.

They eat a lot of olive oil in Italy and Greece - they eat almost no dietary fat in Okinawa Japan and they have the greatest longevity in the world in 1970 - they eat almost no dietary fat, about 6 - 7%” In response, Kresser says “First of all, everything we eat has all the fats in it… Does it make sense that you could eat mackeral and you know the polyunsaturated fats in it are good for you but the saturated fat in it is bad for you?“

“… and in fact, two tablespoons of olive oil has more saturated fat than a 7 oz pork chop.” Actually this isn’t quite right as a 7oz pork chop will give you 7g of saturated fat vs. 4g from two tablespoons of olive oil, but if Kresser had compared by calories, Olive Oil would give you more a little bit more saturated fat. Also, let me comment on this idea that they eat almost no dietary fat in Okinawa Japan.

In Okinawan restaurants in Tokyo and Okinawa, most of the dishes you see are …pork. Pork belly, pork ribs, pig innard soup, pig ears, pig feet and so on. And if you go to the Okinawa prefectural website and click on “food culture,” it says that “Ryukyu cuisine begins with pork and ends with pork.”

Historically, the pig population of Okinawa was very high, reaching 110,000 pigs - that is 1 pig for every 6 people before World War 2. Tragically, the devastation of the war cut the Okinawan population almost in half and destroyed most of their food supply.

The pork population was cut down almost 90% to just 14,000. You may have heard that the Okinawan has nearly 70% of calories coming from purple sweet potato and just 3% from saturated fat. But the survey that found this was conducted in 1949, when people were still struggling to avoid starvation in the aftermath of the war.

However, just 14 years after the war, the Okinawan pig population surpassed its previous high reaching 142,000 in 1960. Moving on, around the 45 minute mark, Kresser references this paper by Zoe Harcombe that reviews meta-analyses of randomized controlled trials before 1983, and says “No randomised controlled trial had tested government dietary fat recommendations before their introduction,” it concludes that reducing blood cholesterol “did not result in significant differences in CHD or all-cause mortality.”

Randomized controlled trials and their meta-analyses are widely regarded as a very strong piece of evidence, especially in comparison to epidemiology studies. Meaning dietary recommendations to limit saturated fat were introduced without proper evidence for them. So how did they stay on this topic for the next hour?

Well there were a couple reasons: Kresser early on pointed out that we should be focused not on whether saturated fat increases cholesterol, but on whether saturated fat actually directly increases heart disease or all cause mortality.

“The other problem is they were using cholesterol as a proxy marker - they weren’t looking at did people eat saturated fat and die more, they looked at did saturated fat increase cholesterol?” However, Kresser at times was questioning whether saturated fat increases cholesterol on average.

This muddled his argument about looking at end points, and the data seems to be on Kahn’s side here- “You add saturated fat, cholesterol skyrockets on average, not in a single person.” as Chris Masterjohn points out in his own analysis of this debate: “Kresser was mistaken to say that saturated fat on average does not raise cholesterol levels.

What you see on the screen is data from the LA veterans administration hospital study. This is reflecting the main difference, which is the difference between saturated fat on the top and polyunsaturated fat on the bottom and over the course of 1, 2, 3, 4, 5, 6, 7 years, right up until the study was terminated, although the cholesterol levels changed over time, this big gap between the two diets remained.”

Also, throughout this section, Kresser brings up several meta analyses of randomized controlled trials in favor of low carb diets, which are expected to be higher in saturated fat, “there have been several metaanalyses now that have looked at low carb diets and all of these meta analyses have found that low carb diets are superior for glycemic control, for reducing insulin, for reducing triglycerides without increasing cardiovascular risk markers - so now we’re talking about randomized controlled trials which is the best form of evidence that we have and we’re not seeing any harm from increased consumption of saturated fat.” In response to this it would have been a good idea for Kahn to just point out that it would be too time consuming for them to sit down and analyze these studies and move on.

But, when asked to address or explain what is wrong with these studies Kresser has brought up, Kahn dodged the question several times over a period of about 50 minutes and Joe Rogan had to keep bringing the question back up.

“Why are you dismissing this new evidence?” “What is your response though to all these studies that he was citing?” “These new studies that he’s showing, and we can go over them again, but you didn’t address why- you did?” “get kids healthy-“ “Please, please, what is wrong with what he said?” “What’s your take on what he said though?”

“Well I don’t care honestly what he said, I’ve got to go with the best science in the world because I deal with patients who have serious disease…” “I think we should move on, but-“ “No we definitely shouldn’t because we’re not- we’re not really clearing this up. What is he saying that’s wrong?”

“Okay, the biochemistry that saturated fat in your diet will lower the number of LDL receptors on your liver and your blood cholesterol goes up. Then you get to epidemiology-“ “Okay but do you understand that he’s, he’s saying something totally different. You’re citing epidemiology studies-“

“Well I started with Biochemistry, then I went to epidemiology-“ “I want to know what’s wrong with what he said…” “Because he’s not being broad with the science.” “Okay but what’s these studies that he’s talking about.” “They’re pixel mentalities. Picking one…” “I’m trying to boil this down - so what is your take on that?

Without any references to the past and people who lived in Mongolia that lived longer…” “These are three disruptive randomized trials from 2010 on that questioned the relationship-“ “No, those are different trials, Joel. I’m not referring to Krause’s research or Chaudhry’s.” “What is wrong with what he’s saying?

“It takes a heretical conspiracy attitude to say everybody’s got it wrong for 60 years. 21 international societies have it wrong - they could…” “So he’s saying that the current science is showing that there is no negative consequence of saturated fat.” “That’s BS. That’s BS.” “So what is wrong with these studies that he’s citing?”

“I don’t know, I have not read every article in the world, nor has Chris. There are three famous studies that I’ve read. Seri Torino Chaudhry and DeSuza, those have been dissected, those are generally-“ “Those were not the ones that I cited anyways.”

Joe Rogan’s constant challenging of Kahn to address this question may be why some commenters felt Rogan was biased in the debate. But, the same thing happened when Kresser made a mistake. He was wrong about the dietary guidelines having changed their position on total fat intake in 2010, and Rogan challenged Kresser multiple times to get this point addressed. “Is that a mistake, Chris?”

“It’s right here…” “Can we find it because these seems like a major point of dispute.” “Lemme, can I stop you because I really think we should clarify that.” “So what was it that you remembered from 2010 and did you remember it erroneously?” “Umm. Let’s see here.”

“Did you find out if you made an error on this 2010 requirement from the USDA?” “So, I don’t have the full guidelines in front of me and I’m not sure what the language says so I could have made an error, it’s possible.”

Finally moving on, at the 1 hour 58 minute mark they discuss the point that saturated fat combined with sugar is particularly bad. In the context of a super low carb high fat ketogenic diet, dietary fat will actually decrease blood levels of saturated fatty acids.

On the other hand, refined carbohydrates will increase them “You eat a lot of sugar, you activate another aging pathway called p-KRas.” Kahn also argues that meat inherently accelerates the aging process due to its effects on MTOR and IGF-1, and he cites this paper by Morgan Levine that shows that high animal protein intake increases cancer, overall mortality and IGF-1 in people.

Interestingly, the paper mentions that specifically, low protein may be beneficial if you’re between the ages of 45 and 65, but if you’re over 65, low protein can be detrimental. In any case, Dr. Kahn says that the methionine in animal protein is what stimulates aging via the mTOR pathway, but as Chris Masterjohn points out in his breakdown video “Methionine is an amino acid and you can divide it into two components.

One is there’s a basic skeleton of that amino acid and on top of that, there’s what we call a methyl group. That methyl group is what supports an entire system in the body called methylation that is important to all kinds of mental and physical health.”

for methionine to stimulate mTOR it needs to donate a methyl group. So if you have too much methionine, you’d have too many methyl groups and you could accelerate aging. But, we have an amino acid called glycine that acts as a buffer for too many methyl groups.

So if you’re getting methionine from muscle meat, it’s not an issue if you’re eating other glycine rich parts of the animal like connective tissue and skin, or drinking bone broth. The other worry about meat is homocysteine, homocysteine is well known for its apparent contribution to heart disease. So, once methionine donates that methyl group, it becomes homocysteine.

But, In order to get rid of the homocysteine, you need all the B vitamins. And… animal foods are quite high in B vitamins. Shifting topics, around the 2 hour 29 minute mark, Dr. Kahn brings up TMAO: “TMAO. If you eat red meat which is rich in L-Carnitine, another amino acid, if you eat eggs that’s rich in choline, those directly led your liver to create TMAO. What does TMAO do?

It stuns your HDL so it doesn’t reverse cholesterol transport, it causes LDL to enter the cell wall to create foam cells, macrophages, plaque and you get a heart attack.” “Actually Joel, what in the diet increases TMAO orders of magnitude more- “-fish! Because fish has it right in there fish flesh along with that mercury and their PCB’s and…”

“-What would most doctors and researchers say about fish consumption and cardiovascular disease and mortality. There are few things that are associated with a greater decrease in cardiovascular disease risk than fish consumption. And… TMAO, if you look at a graph - the increase in TMAO from eggs, beef, cheese, milk, clams and then look at cod and halibut.

Cod and halibut are increasing TMAO, as I said, orders of magnitude more than beef or eggs. You can’t even see eggs and beef there and fish consumption, I think almost every public health authority would recommend-would agree with this is reducing the risk of heart disease and mortality so the other thing about TMAO to know is that certain types of gut bacteria metabolize choline and carnitine into TMAO whereas others don’t.

A lot of scientists have speculated that high TMAO levels are essentially a result of a disrupted gut microbiome. There’s studies showing that rifaxamin which is an antibiotic that treats bacterial overgrowth in the small intestine reduces serum TMAO levels. Which suggests that it’s mediated by the gut microbiome.”

The conversation on TMAO eventually fizzled out and later on Kahn and Kresser agreed that you should up your veggies in any case. Kresser said your plate should be ⅔ to ¾ plants. Around the 3 hour 4 minute mark, Joe Rogan asked Kresser what the benefit is of “putting that one quarter of your plate - putting animal protein.”

“There are lots of benefits, animal protein is more nutrient dense in essential nutrients - animal foods are higher in B12, bioavailable Zinc, Iron, Calcium, Choline, Taurine, Creatine and not just higher in terms of the actual amounts, but higher in the amount that you absorb and that’s a very key point.”  Joe Rogan then asks what would be negative about removing the animal products from that one quarter of your plate.

Kresser begins by explaining you would end up lacking B12, and he says that more important than looking at what is theoretically possible, that is, instead of seeing whether it’s possible fill in this B12 lack with supplements, what’s important is checking the actual incidence of deficiencies. “for example, the average omnivore - the rate of B12 depletion is 11% and then for vegetarians, it’s 77% and for vegans it’s 92% of depletion which is the first stage - there’s four stages of B12 deficiency and that’s the first stage.”

As was discussed earlier in the video, you want to keep homocysteine down and you need B vitamins like B12 to do that. This study also found that 16% of the omnivores, 38% of the vegetarians and 67% of the vegans had high homocysteine levels.

“A lot of people turn to a no animal product diet to improve their cardiovascular health and yet you’re seeing much higher rates of homocysteine like the average in vegans is 16, which is clearly associated with increased risk of not only cardiovascular disease but also dementia and alzheimer’s.” This a point where Kahn seemed to agree with Kresser.

“Chris I couldn’t agree more, I’ve written many articles- ‘don’t be a dumb vegan’… and I don’t mean to offend but y’know… We are prone to have a few holes in the wall that an intelligent person knows how to plug. It’s Vitamin D, it’s DHA, B12, Iodine, Taurine, Vanadium, Chromium, I just got those, that’s what I do every other day. I’m totally complete.”

“But let’s look at things like Calcium, Iron, Zinc, Choline, Creatine, Retinol which is preformed Vitamin A, let’s look at EPA and DHA. All of these are shown to be lower in vegetarians and vegans than they are in omnivores.” Next, Kresser talks about whether or not it’s a good idea to rely on supplements. “Yes, you can supplement, but it just- do the supplements have the same effect?

Like look at calcium. Dietary calcium has inversely related to heart disease and kidney stones. But when you look at studies on calcium supplements, the opposite is true. Calcium supplements are associated with an increase in heart disease and an increase in kidney stones.

But the theory is that supplemental calcium is not the same as dietary calcium - you get a large bolus of calcium that goes into your blood all at once and then it can get into the soft tissues - which, Joel will tell you, is not good for your heart health. My point is that supplements don’t always affect the body in the same way…. I just think it’s better to get nutrients from food if you can because that’s the way we’ve been getting them for millions of years, y’know.

“Just to show how nutrient dense organ meats and shellfish are: You could eat 1 clam, 1 oyster, and four grams of liver a day and you would completely meet your needs for B12, Zinc, Copper, Choline and many other nutrients with no other consumption of animal foods.” Moving onto the 3 hour 19 minute mark, they briefly talk about the carnivore diet.

“I am baffled by this carnivore diet.” Dr. Kahn and Joe Rogan talk about how Vitamin C may not be an issue because glucose competes with vitamin C for uptake, so the little Vitamin C these carnivore people get from organ meats and muscle meat could be sufficient because they use it very efficiently.

Kresser has a theory that the people benefitting from this are experiencing something like a gut rest. “Meat is absorbed very high up in the digestive tract- when you only eat meat, it’s a low residue diet. And there’s nothing left over to irritate or inflame the gut, my theory is a lot of people who are benefitting from this have a really disrupted gut microbiome and the carnivore diet is essentially like a gut rest or a fast, and so I don’t doubt that people are benefitting from it - the question is what is the long term implication.”

Other than that a big concern was how well people will fare without phytonutrients and fiber. “Should we wrap this up? One thing that we came to a really solid conclusion is the standard american diet sucks.”

All in all both sides had interesting points to contribute to the debate and the video is worth watching or listening to, though I’d recommend to start watching from about the two hour mark as I felt the second half was more productive and interesting.