Simple Nutrition Insights

The Dangerous Truth About the Carnivore Diet

• Leonila • Season 2 • Episode 18

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We examine why the carnivore diet—an eating pattern eliminating all plant foods—poses serious health risks despite its trending popularity. This restrictive approach creates dangerous nutritional gaps that develop gradually over time, potentially leading to severe long-term consequences.

• The carnivore diet eliminates all plant foods, creating critical nutrient deficiencies
• Complete absence of fiber increases colorectal cancer risk substantially
• Vitamin C deficiency can lead to scurvy symptoms including fatigue and poor healing
• Lacking antioxidants and phytonutrients leaves cells vulnerable to oxidative damage
• Without prebiotic fiber, gut microbiome becomes compromised, increasing inflammation
• High meat consumption classified by WHO as carcinogenic or probably carcinogenic
• Increased animal protein consumption places significant stress on kidney function
• Heart health suffers from increased saturated fat intake without fiber's protective effects
• There are no long-term studies showing carnivore diet safety, but significant evidence of risks
• Monitoring labs regularly helps track internal health markers before problems become serious

Check your labs regularly to understand your health trends—especially kidney function, which declines long before symptoms appear. Work with a registered dietitian before making significant dietary changes to ensure your nutritional needs are met while supporting your specific health goals.

Assessing the nutrient composition of the carnivore diet 

Long Term Concerns of the Carnivore Diet 

Dietary fibre, whole grains, and risk of colorectal cancer: systematic review and dose-response meta-analysis of prospective studies

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Speaker 1:

Hey, hey, welcome back to another episode in the Simple Nutrition Insights Podcast. I am your host, leonila Campos, registered Dietitian, and today I want to talk about a topic that I talked about last year, probably around this time, maybe earlier, but it is interesting how trends work. It is interesting how diets work because they do go through phases, right, like you have a phase where, like, a ton of people are doing it and then it dies out, right, and then next year comes around and the same thing. So I've been seeing more and more about this diet specifically, and more people, more of my clients, have asked me. So I said you know what? It seems like it's trending again and that is the carnivore diet. So if you haven't heard about it, that's probably a good thing.

Speaker 1:

But the carnivore diet basically eliminates all plant-based foods and it's just all animal products. Right, it might sound simple, but is it safe? As a dietician, I have serious concerns, especially regarding nutrient deficiencies and the long-term health risk of cutting out fiber, including an increased risk of cancer. So let's break it down. I'm going to give you the information that you need, the knowledge that you need research-backed information, because I want you to make an informed decision and in order to do that, you have to have the right information, not information that a friend gave you or an influencer gave you, or someone that says you know gives you these claims that are probably not true, right? So you have to know, you have to have the right information to really, really and truly make an informed decision. Ultimately, in the end, it's your decision, so you do whatever you want to do. Ultimately, in the end, is your decision, so you do whatever you want to do. So, for those unfamiliar, the carnivore diet is an all meat diet, strictly animal-based foods like beef, chicken, fish, eggs and some dairy. It's missing your fruits, your vegetables, your whole grains, nuts, seeds and legumes basically every source of fiber and wide variety of essential vitamins and minerals.

Speaker 1:

Many people claim they feel great on this diet, but short-term benefits do not outweigh long-term consequences. Without fiber and key micronutrients, this diet may actually put people at a higher risk of serious health issues, including colorectal cancer. Now, oftentimes we focus on the short-term wins, right? I don't even know if I call them wins, but on the short-term effects, right. So if we're looking at a diet because we want to lose weight, we look at how fast we do it, right? Or we look at the short-term results but we don't look at the long-term right, like, if I continue to do this for the rest of my life, what are the health consequences? Right, what are the health risks? And I don't think that you want to find out being on a carnivore diet, because that means that you can potentially develop cancer, colorectal cancer. Of course you don't want to mess with that, right. But your deficiencies you don't see those happening right away. Right, like, it's not going to happen in a year, it's not going to happen in two years. You'll start to see it longer and a longer period of time. Right, because you're not adding these nutrients that your body needs and it goes.

Speaker 1:

Adding these nutrients that your body needs and it goes, literally goes against everything we have learned in nutrition, right, and all the research that has been done to back up the five food groups, right. I know some people have said that my pyramid, bro, that has been phased out many years ago. Right, we don't use the pyramid as dietitians. We haven't used the pyramid in so many years. It's the MyPlate, it's the five-food groups, it's, you know, making these balanced meals, because it shows that when we do add those five-food groups, we get the nutrients that our bodies need without having to supplement if we don't need to. I have also heard oh well, if you just go into the carnivore diet, you can supplement. Okay, that is. You know. We want to do that. Imagine how many pills you have to take to be able to supplement everything that you're not getting from all the other four food groups that you're eliminating right Now.

Speaker 1:

What I always tell my clients a supplement is just that. Right, it's going to fill in the gap that you're not getting from your food, for whatever reason. Right, it shouldn't be a significant amount, because we should be getting the nutrients from food, and the supplement is just in case you're not getting it. Right Now. The other thing, too, is that supplements your body's not going to absorb everything 100 in the supplement, right, it's just going to absorb whatever it needs and that is it. But you're only getting what's on the supplement, right? So, for example, if you're like, well, I just take a fiber supplement, okay, that is it right. If we add the actual food, right, your plant sources, they're going to give you more than sources. They're going to give you more than the fiber. They're going to give you antioxidants and vital chemicals and prebiotic fiber right, and some are going to give you some probiotic. So it gives you a wide variety of other nutrients and just taking a fiber supplement or just taking a vitamin B supplement whatever or just taking a vitamin B supplement whatever so the food will give you so many other nutrients other than just the specific nutrient right Macronutrient that you're not getting. But the other thing, too, is that is your body really absorbing it right and to what extent? So definitely keep those things in mind.

Speaker 1:

Now let's focus a little bit on the danger of nutrient deficiencies. Let's talk about what's missing when you eliminate plant-based foods Vitamin C deficiency. Vitamin C is crucial for immune function, collagen production and iron absorption. Without fruits and vegetables, you risk developing scurvy, a disease of vitamin C deficiency that leads to fatigue, gum disease and poor wound healing. There was a case I mean this is many years ago, but there was a case when I think a ship was traveling from like Europe to America and they didn't have any fruits and vegetables right. They were essentially eating the carnivore diet and they were trying to figure out when they arrived. They were trying to figure out why it says that they were having impaired wound healing and they were having gum disease and it was because of vitamin C deficiency, scurvy, right. That's how it came about, and so just by adding some of those fruits and vegetables, that was resolved. So you can look it up, look at, look up scurvy, and you know the history behind it.

Speaker 1:

I'm not making this up, and so that can absolutely happen. Now you might say, well, I'll just take a vitamin c supplement, right, and your body will absorb whatever it needs. But too much vitamin c, right, let's say, from a supplement you really usually don't worry from food sources, right, because your body is so efficient at metabolizing that, using what it needs and then getting rid of it through the urine, through your kidneys. But a high dose of vitamin C on a consistent basis, right, can lead to kidney stones, right. So I don't think you want kidney stones. And then, on top of that, if you are increasing your meat intake, right, that can also increase your uric acid, which can lead to gout but also can cause kidney stones, right? So see where I'm going here, versus getting it from your food sources.

Speaker 1:

Folate deficiency Folate is found in leafy greens, beans and fortified grains. Folate is essential for DNA synthesis and cell repair. Now, folate is extremely essential for women of childbearing age or for women that are hoping to get pregnant. Right, there's usually, in this case, there is a need for a supplement of folic acid because it helps with neural tube, prevents neural tube defects. Right, like spina bifida, because there's a fast turnaround in DNA. Right, you're creating a human being and so sometimes we're not able to get enough from food and so you have to supplement. But you know, for the general population, getting it from these food sources, again, you're not only going to get the folate right Well, you're going only going to get the folate right. Where you're going to get other nutrients, but low folate levels, you know having linked to higher risk of cancers, particularly colorectal cancer. So think about that.

Speaker 1:

Antioxidant deficiencies your antioxidants, such as vitamin A, e and phytonutrients from plants, help protect cells from damage. Without them, the body is more susceptible to oxidative stress, which can contribute to chronic disease, including cancer and heart disease. Now, vitamin A and E are your fat-soluble vitamins. There is a risk, right, of getting too much from a supplement. Again, because usually in a supplement, especially if it goes over 100% of the daily value basically what you need in a day it stores in your fat cells and the more that you take, the more you store and it could get into toxicity levels, right? So, versus with food, again, your body utilizes what it needs and then you get rid of it, but you also store some of it in your fat cells, but not significantly. Versus when you take a supplement, that is a higher amount. Now, your antioxidants, which is your vitamin A and E, and your phytonutrients there are so many other ones, but these are just a few from plant sources. Think of it as like a little fighter, right? Antioxidants that are protecting your cells from damage. So this is at a cellular level, right? There's a lot of oxidative stress because of actual chronic stress because of the environment, because of other toxins, chronic stress because of the environment, because of other toxins, and so those nutrients, right, those antioxidants are healing and protecting your cells from that increase in oxidative stress. Free radicals, right, that damage the cells. So we need them, right? These are things that we need on a day-to-day basis coming from food, right, because we get these phytonutrients right from our plant sources.

Speaker 1:

Lack of prebiotics for gut health Prebiotics are found in fiber-rich foods that feed beneficial gut bacteria or your gut microbiome. Without them, the gut microbiome is compromised, leading to inflammation and an increased risk of metabolic disorders. I did an episode on microbiome and the importance of it. These little microbes, right, the bacteria that we have in our gut. They protect us, right, they have so many functions that we have in our gut. They protect us, right, they have so many functions, but specifically with inflammation, right, they keep inflammation down, they fight inflammation, they help with the oxidative stress, but they need fuel, right, and the fuel is going to come from plant sources, it's going to come from the prebiotic fiber, right, and so without that right, if we're not feeding the microbiome, it starts to die out. But it also, some of them, start to eat on that lining of the stomach right and that mucosal lining of the stomach, which is the protective barrier right that protects from the lining of the stomach into the bloodstream. So that increases inflammation. But there's also a higher risk of getting more infections, of getting more diseases, you know metabolic conditions and so, and it's because we're not feeding them right, the prebiotic fiber that we get from plant sources, and that is dangerous, right, because we have all these things happening and again, they're not going to happen right away, it's going to be a progression, it's going to be chronic, right, long-term. And when you do catch it, sometimes it's too late, right, and why do we want to mess with that?

Speaker 1:

Let's focus a little bit more on the critical role of fiber in cancer prevention. One of the biggest red flags with the carnivore diet, as we mentioned, is the complete elimination of dietary fiber. Here's the risk, or here's the why fiber is not a non-negotiable for long-term health, specifically for colon health and cancer prevention. Fiber helps keep the digestive tract moving, reducing the time waste that sits in the colon. Right, because when you think about constipation, that means that when you don't go to the restroom for number two to have a bowel movement, that means that they waste. Right, because you continue to eat and your body continues to metabolize and digest food and it creates waste. That waste travels to the colon. Right, because you continue to eat and your body continues to metabolize and digest food and it creates waste. That waste travels to the colon, right Into the large intestine, into the colon, to be, you know, removed. If that is not happening daily, I'm telling you daily you have to go poop daily. If that is not happening daily, that waste is just sitting in your colon, in your large intestine, right? So these toxins are just, you know, just there, getting absorbed, just there, right, essentially damaging the colon.

Speaker 1:

And so if you have constipation, you have to look at your fiber intake and your hydration, right, and if that doesn't improve, right, working with your GI specialist to figure out why. Right, because we have to be having a bowel movement daily, unless if you're, you know, not eating very much or there are other, you know, health conditions that you know you don't go to the restroom as often, but when you do go it's not actual constipation, you still have, you know, a form such as like bowel movement. There's no straining, you know. Then we're okay. If you're having issues not so much with that but using your pelvic muscles to be able to eliminate, then work with a pelvic floor specialist, because that's more so of a and I'm sure my physical therapist friends are going to kill me for that, but I don't know the right word right, but that is the structural part of your pelvic floor, right? So there are resources there that they can help you with that if that is the problem. Resources there that you can have that they can help you with that if that is the problem.

Speaker 1:

So the world cancer research fund in the american institute of for cancer, research confirmed that high fiber intake lowers the risk of colorectal cancer. You know, as it makes sense because if you're having fiber and you're drinking enough water and you're using the restroom daily, right, having those nicely formed bowel movements, and essentially you're eliminating the waste, right, whatever, your body is not using the dead cells through your digestive tract. Whatever toxins are in your digestive system, you remove them. When you have a bowel movement, right, and that's perfect because it's out and you don't have to worry about it. Without fiber, harmful toxins and carcinogens have prolonged contact with the intestinal lining, increasing the risk of DNA damage and tumor formation. So again, I can't emphasize this enough If you have constipation, if you have issues or trouble going to the restroom, if you don't go to the restroom daily and have a nice form bowel movement, please talk to your doctor, talk to your dietician, talk to your GI specialist, your pelvic floor specialist, to try to figure out why that is the case.

Speaker 1:

Short-chain fatty acid and inflammation. When fiber ferments in the gut, it produces short-chain fatty acids like butyrate, which have anti-inflammatory and anti-cancer properties. A fiber-free diet, meaning that you're not adding any fiber, like in the carnivore diet. It reduces butyrate production, leading to increased inflammation and potential tumor growth. Reduces butyrate production, leading to increased inflammation and potential tumor growth. Gut microbiome and immune function Fiber feeds good gut bacteria, as I mentioned, helping maintain a balanced microbiome.

Speaker 1:

Diets high in red meat and low in fiber shift the microbiome toward inflammation and disease risk. So when we remove fiber entirely, we're removing one of the strongest natural protectors against colorectal cancer. That is powerful. So when you think about not adding your fiber, think about that risk right. And if you already have risk or history of cancer or colorectal cancer, you don't want to mess with that right Because you're removing something that is so powerful and that is protecting you. It's protecting your system. It's protecting your entire human being, human body. So who should be concerned? This isn't just about theoretical risk.

Speaker 1:

Studies have shown real consequences of low-fiber, high-meat diets. A 2015 study from the World Health Organization classified processed meats as a group 1 carcinogen, meaning that there's strong evidence they cause cancer. Red meat is classified as a probable carcinogen, with excessive intake linked to higher colorectal cancer risk. A 2023 study in the Lancet confirmed that fiber-rich diets lower risk of many chronic diseases, including heart disease and colorectal cancer. So I didn't really talk about the risk of heart health or cardiovascular health.

Speaker 1:

When you increase your animal products, naturally you're going to increase respectively you're going to increase the amount of saturated fat that you're consuming, the amount of trans fat that you're consuming and the amount of cholesterol that you're consuming, consuming the amount of trans fat that you're consuming and the amount of cholesterol that you're consuming. So if you already have issues with cholesterol, you're multiplying that by a lot. Right, because now you are increasing that intake but also eliminating the fiber, which the fiber helps to lower cholesterol. So imagine how much work, how much a risk you're putting your heart and your cardiovascular health by doing that. Right, and I know there's so many influencers, there's so many people, even a doctor that says don't worry about your cholesterol.

Speaker 1:

Oh my gosh, I don't even know, I can't even talk about that. But if someone says don't worry about your cholesterol and your heart health, you should not listen to them. Right, because there's so much research and so much literature that shows that we should worry about our cholesterol and our bad cholesterol and our total cholesterol when it comes to cardiovascular health and getting a heart attack or a stroke. Right, because there's so much research that shows that. And so if we have high cholesterol, we are at a higher risk of having a heart attack and a stroke. And then you eliminate fiber, you eliminate your plant sources, you eliminate your phytochemicals right, and those you know, your vitamin, your antioxidants that are helping you with protecting your cells, right. We're almost like a ticking bomb here. So that's, you know, overall, in our bodies, in just general.

Speaker 1:

Now we haven't even talked about the load that it puts our kidneys right as you increase your protein, your animal protein. It puts a kidneys right as you increase your protein, your animal protein. It puts a huge load on the kidneys right, because your kidneys are the ones that have to. They have to eliminate the waste of meat by the waste of animal products, and that you know and it turns into blu-ray, nitrogen and creatinine, and so in creatine, creatinine that's what I meant to say. And so if you already have kidney issues, which the majority of the population have no idea what their kidney function is. So here is a call to action for you you need to know what your kidney function is and what the trends have been for the past five years longer if you need to, but at least for the past three to five years. Because if your kidney function has been declining which it does it does 1% every so often, natural. But if it's 5%, 10%, that is significant, right, because now we're going to get into chronic kidney disease.

Speaker 1:

And if that is the case, right, going into the carnivore diet is not going to help your kidneys. On the contrary, you are going to damage your kidneys to dialysis. Pay attention to your labs, pay attention to what your body is telling you and don't go into these extremes. Right, I know I'm giving it sounds like you know on the opposite here and you're like this is so biased, but it is not. I'm giving you the information that is available.

Speaker 1:

As a dietician, I don't support the carnivore diet at all. When my clients ask me, I give them this information and we go and we talk about the research. We talked about what it has shown. We don't have, you know, long studies yet, right, of the risk that it has for someone that has been on the carnivore diet for a long period of time. But even influencers that started saying, oh, follow that and whatever and whatever. They started to add plant sources because they were feeling sick, right, and they needed to add antioxidants blueberries, strawberries, whatever. They needed to add these plant sources to be able to feel better, because our bodies need that. Right? These are nutrients that our bodies need to function properly and heal and repair.

Speaker 1:

So don't just focus on what you want to do short term. Think about the long-term consequences. Think about your health risk already. If you already have family history or issues with cancer, don't mess with it. Right? You don't want to find out or you don't want to say I wish I've known right, or I wish someone would have told me, or I wish I have known the risk, right. I'm telling you the risk right now so you can make an informed decision.

Speaker 1:

As I mentioned at the beginning, ultimately it's going to be your choice, right, but I want you to really really think about the long-term consequences Instead, right, what we can do. It really comes back to, instead, right, what we can do. It really comes back to having these balanced meals right, adding a variety of these five food groups and making sure that you're getting the nutrients from your foods right and adding a variety whenever you can, instead of focusing on something so restrictive, just like any other diet. Right? We know that they're not going to work long term Once we stop doing them. Whatever results we got, right, we're going to lose them, and then it's going to be twice as more, twice as harder, right to deal with it and have to start something new again. So save yourself some time. Save yourself your money right from any supplements that whoever is trying to sell you, because you know that's how they have an agenda and that's how they are going to get their money.

Speaker 1:

So, although, while the carnivore diet might seem like an easy way to eliminate quote-unquote bad foods, I don't like that word. There's not a good or bad food, it's just the amount that we consume. It comes at a cost, with nutrient deficiencies, just the amount that we consume. It comes at a cost, with nutrient deficiencies, increased disease risk and potential long-term health complications. And I don't want you to take this also in the opposite way. Right, I'm saying you should not have red meat, you should not have animal products. No, again, the work here is how are we going to balance these meals? How are we going to make sure that we're adding our plant sources to help with the fiber, to help our heart health, to help our brain function right, to help with healing and recovering and repairing? Right? It is truly a balance without complicating it. Right? If we add all these foods from these five food groups and we make these balanced meals, that's all we really need to focus on, right?

Speaker 1:

Essentially, if you're considering a restrictive diet like that, like the carnivore diet, I strongly urge you to speak with a dietitian or healthcare professional first. Right, we are going to look at deeply into your labs, right? I always ask my patients check your labs. Right, if I know there is diabetes or high blood pressure, I encourage them to check their kidney function and to make sure that they check the trends. Right, because I often get and I'm going a little bit off topic here, but I often get these comments you know, I didn't have chronic kidney disease or I didn't know that my kidneys were failing and all of a sudden I am in renal failure.

Speaker 1:

That is not the case. There are signs. If there's chronic kidney disease, it's chronic for a reason. It has been happening for a while now. If it's acute kidney injury, that is different, because that happens fast, right, and oftentimes we'll recover. But if it's chronic kidney disease, that has been happening for years, right, and either we, you know, sometimes we don't know. We don't know what to ask. If we don't know, we don't know, but usually the labs will tell you that, right, okay, your kidney function has been declining for the past five years. Right, you had a GFR, glomerular filtration rate, which measures kidney function one of them. It was at 100 five years ago. It's been, you know. Now we are, I don't know, we are a 50, right, so now we're in chronic kidney disease stage.

Speaker 1:

So you really have to look at your labs. Don't just go and do labs and be like, oh okay, I did the labs. My doctor said everything was okay. Go and do labs and be like, oh okay, I did the labs. My doctor said everything was okay and that is all. You have to ask questions right, okay, how were my labs the year before? Or you have to compare them. Right, now that you have my chart or a way to look at your labs, compare the trends of every single lab that you get right, just to see how you are doing internally, and that can give you a lot of information.

Speaker 1:

You can make changes based on that. Or you can work with a dietician and your healthcare provider to make the necessary changes to improve your health. Okay, this was a quick one, but I think it will. You know lots of information. I will link the resources and the research that I quoted on the show notes resources and the research that I quoted on the show notes. So you have it right Again. Please consult with a dietitian with any nutrition change that you want to make or that you feel that you need support with, because you know we will give you the support that you need. If the dietitian that works with you doesn't, is not aligning with your goals or you're feeling that you're not connecting, find another one, right, you definitely have that right, just like when you have that. Just the way that you have that right when working with a doctor, right, or any other professional. All right, until next time, take care of your health and fuel your body wisely. Bye-bye for now.