Diets Debunked: The Carnivore Diet - Dr. Michael Ruscio, DC

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Diets Debunked: The Carnivore Diet

A Second Look at the Health Benefits of This Ancestral-Inspired Diet

Key Takeaways:

  • The carnivore diet is an all-animal diet primarily consisting of red meat, fish, animal fats (like lard), organ meats, eggs, and dairy products.
  • The diet may offer similar health benefits to keto, such as better brain, heart, and immune health.
  • The high-protein content of the diet may also be responsible for its health effects.
  • Though the scientific evidence is scarce, when the carnivore diet is followed appropriately, it supposedly has little risk for nutrient deficiencies or other adverse effects.
  • This means that eating organ meats, like liver, is essential while on a meat-based diet.
  • For most people looking to resolve their health symptoms, modifying the carnivore diet to be a short-term elimination diet is sufficient.
  • You may benefit from a short-term animal-based diet if you have a hypersensitivity to foods and have responded poorly to more relaxed elimination diets.

Though the carnivore diet has been around for over a century, it’s only within the last 6–7 years that it has made its way back into pop culture — largely thanks to a few highly-influential podcasters. The carnivore diet involves eating only animal products like meat, fish, and eggs, and proponents claim that it is nothing short of a miracle cure for numerous diseases. There have been numerous reports of it being beneficial for everything from autoimmunity to eczema to weight loss. 

However, the extremely restrictive nature of the diet has also raised concern for its consequences on long-term mental and physical health, and higher risk for nutrient deficiencies. Today I’ll step away from pop culture and explore the history, science, and benefits of the diet, and see what we can take home from this ancestral-inspired eating pattern.

This article is part of our “Diets Debunked” series, so be sure to check out my other articles where I uncover the myths, scope out the benefits, and offer alternatives for other diet trends.

What is The Carnivore Diet?

At the risk of over-simplifying this ancestrally-inspired diet, the carnivore diet is a meat-based diet that excludes all carbohydrate sources (if you’re thinking keto, you’re right on track). It is highly restrictive, only allowing the following 3 food groups [1]:

  • Proteins: Beef (grass-fed is best), chicken, pork, some fish
  • Animal fats: Primarily from the above meat sources
  • Organ meats: Liver, kidney, bone marrow, etc.

This diet can also include other animal foods like dairy and eggs, and encourages the use of all animal parts, such as cartilage and bones which can be used to make bone broth [1]. While its high-fat, zero-carb nature makes it inherently ketogenic, it is distinctly different from a traditional keto diet, as it completely eliminates plant foods

Off-limit foods include [2]. 

  • Nuts and seeds
  • Legumes
  • Whole grains
  • Fruits
  • Vegetables
  • All other plant-based foods

The Origin Story of All-Meat Diets

As discussed with Dr. Paul Saladino on my podcast, the concept of the diet originated in the early 1900s with an arctic explorer, Vilhjalmur Stefansson, who ensconced himself in the Inuit culture for nearly a decade. During this time, he adopted their diet that consisted entirely of animal meats and fats. He noticed a nearly complete absence of chronic diseases like obesity, heart disease, and cancer in their culture, and saw a vast improvement in his personal health. 

Upon his return, he was checked in-to a hospital in New York for observation where he continued with a meat-based diet for several years. The team of doctors and researchers were surprised to find that he was completely healthy and published their findings in 1930 [3]. 

The Benefits of the Carnivore Diet

While there are no clinical trials that assess the benefits of an all-meat diet, there are a few case studies and a plethora of anecdotal evidence that support its use [2]. A 2021 survey involving over 2,000 participants who had been on a carnivore diet for at least 6 months showed they had high levels of satisfaction with the diet. 

The participants had self-reported improvements in [1]:

  • Sleep disturbance
  • Fatigue
  • Brain fog, cognition, and mental clarity
  • Being overweight or underweight
  • Blood sugar dysregulation (type 1 and 2 diabetes and metabolic syndrome)
  • Autoimmunity 
  • Joint and muscle pain
  • Mental health
  • Skin issues
  • Urinary difficulties

This study suggests that a meat-based diet can be beneficial for health, though much more research is needed to determine the long-term health effects of the diet. But just because the science is scarce, it doesn’t mean that this diet doesn’t have merit when used appropriately. 

Before we jump into how to use it safely, let’s look into a closely related diet that can give us deeper insight into what benefits a low-carb, high-fat diet has to offer.

An Evidence-Based Cousin — The Ketogenic Diet

Though the literature on the carnivore is scanty, theoretically, the carnivore diet could provide similar benefits to the well-researched ketogenic diet. The keto diet is low-carb (not no-carb), high-fat, and moderate-protein, but is less restrictive than the carnivore diet, as it allows plant-based foods [4]. 

It promotes the use of plant-based fats like olive oil and avocados and is full of vegetables and allows certain fruits. Despite the greater abundance of food choices, it is still highly restrictive in that most carbohydrates are off-limits including grains, corn, sweeteners, and starchy vegetables (like potatoes). 

While the protein content of a keto diet is lower than that of the carnivore diet, a high-protein variation exists for those who feel better with more dietary protein.

The ketogenic diet was originally noted for its profound effects on neurological health, likely due to the production of ketone bodies, which replace glucose as the major source of fuel for the brain during ketosis. 

Ketones are highly anti-inflammatory, particularly for the nervous system, and their neuroprotective benefits have made the keto diet a top therapeutic for those with treatment-resistant epilepsy, traumatic brain injuries, ALS, Alzheimer’s, and other forms of dementia [4]. 

The known benefits of a keto diet have expanded from their early origins in neurological health, and research now shows that it is helpful for [4, 5]:

  • High blood pressure
  • Cardiovascular disease (controversial)
  • Lower body weight and body fat
  • Elevated lipids
  • Thyroid disorders
  • Autoimmunity
  • Type 2 diabetes

The Power of Protein

Along with its potential to induce therapeutic ketosis, it is safe to assume that the carnivore diet’s high protein content is also at the root of its growing popularity and associated health claims. Research shows that high-protein diets can improve metabolic and cardiovascular health, and promote weight loss compared to a low-protein diet [6]. 

Unfortunately, most people aren’t getting enough protein in to meet the updated daily requirement of about 75 grams per day (minimum). This rampant protein deficiency is likely part of the reason why people report significant improvements in energy, clearer thinking, and even better athletic performance while on the carnivore diet. 

Additionally, animal protein has all the essential amino acids that you need and is superior to plant protein in its bioavailability (ability to be absorbed in the GI tract and utilized by the body). Whether it’s accompanied by a carnivore diet or not, for most people, increasing the amount of protein is beneficial for your health. 

How to Make the Carnivore Diet Work

Despite the fact that modern humans are omnivores (consume plant- and animal-based foods), proponents of the carnivore meal plan believe that it is completely safe to stay on long-term. This may sound surprising, as we obtain many of our essential micronutrients from plant-based foods, like fruits and vegetables. However, there are few studies that show a low risk of nutrient deficiencies or poor health outcomes on a meat-only diet [2]. 

But there is a major caveat here — as Dr. Paul Saladino states, if you choose to stay on the carnivore diet long-term, you must incorporate organ meats into your diet. If you don’t, you are at a high risk of becoming deficient in certain nutrients like B vitamins and vitamin C as lean meat alone cannot give you all the nutrients you require. He also has seen that going “carnivore” can even improve your nutrient status by removing irritating foods that inhibit nutrient absorption in the gut.

If organ meats aren’t appealing to you, but you want to reap the benefits of a high-fat, low-carb diet you may want to consider a diet that is a little bit more friendly in terms of the foods that are allowed, like the previously discussed keto diet. On the episode, Dr. Saladino offered a few more tips to help someone get started on the carnivore diet:

  • Increase your fat intake: eating too much lean protein can leave you feeling less than great, as it overwhelms the urea cycle that helps metabolize amino acids (the building blocks of protein). Increasing your fatty cuts of meat, fish, or lard intake and slightly cutting back on meat can help resolve this issue.
  • Include organ meats: as previously discussed, you need to incorporate organ meats like liver and kidney to meet your nutrient requirements. If you are new to organ meats, start with liver and mix it into ground beef to get you started.
  • Start with a fast or modified carnivore diet: if a meat-based diet is too much too soon, start with intermittent fasting before transitioning into a full-blown carnivore diet. Easing in by including foods like honey, squash, and cucumber (low in lectins and oxalates) can also help.
  • Consider food sensitivities: If you are still experiencing symptoms on the carnivore diet, it could be a reaction to eggs, lactose, or fish. You may benefit from temporarily removing them, but be sure to find another iodine source, like iodized salt (though decreasing your sodium intake when you first transition can prevent major blood sugar swings).

The carnivore diet by nature is ketogenic, and you may go through keto-adaptation (“keto-flu”) during the first few weeks on a full carnivore diet. This can cause side effects of gas, bloating, abdominal pain, and loose stool that are likely due to the natural shift in the gut microbiome that occurs when switching to a low-carb diet [7]. While the best you can do is to wait it out, supplementing with electrolytes that contain sodium, potassium, and magnesium can help.

On a final note, long-term health outcomes are unclear for both the keto and carnivore diets and are both controversial on whether they elevate LDL cholesterol, worsen kidney disease, or increase your risk of heart disease. If you follow a highly restrictive or “extreme” diet, it’s always best to regularly check in with your healthcare provider prior to starting and during, especially if you have a serious health condition like cardiovascular disease. 

Step Away From Extremist Diets (But Still Reap the Benefits)

While the above may be good news for some all-meat enthusiasts, not everyone is looking to stay on a highly restrictive diet forever, leaving them feeling discouraged. Unfortunately, I often see that with new diet trends, people can quickly take these concepts to an extreme and see them as the pinnacle of healing.

Highly-restrictive diets like the carnivore diet and keto diet can certainly be beneficial in select cases, but in my experience, most people don’t need to take their diet to that level to see health benefits. Dieting to extreme levels, no matter how “nutritionally healthy”, can take a toll on someone’s psychological health as many enjoy the color, variety, and social aspects of foods. 

To be fair, I have seen in my practice that plant-based foods have become a recent problem, largely due to the growing epidemic of an unhealthy digestive tract. An inflamed gut is highly reactive and is particularly sensitive to certain compounds in raw vegetables, like fiber, oxalates, sulfur, and salicylates. 

Another Take on A Meat-Based Diet

So how do we remedy this issue, without completely removing plants from the diet? When the carnivore diet is re-framed as a “prescription strength” elimination diet with the endpoint of being able to enjoy a broader array of foods, it becomes a little bit more feasible. A 30–60 day diet is a lot less intimidating than a complete lifestyle upheaval. This may not be enough to get the full effects of ketosis, but it can work for many with chronic health issues.

I typically see that those with extremely hyperreactive digestive tracts benefit the most, and 60% of my patients who self-started the carnivore diet have reported benefits. If you are getting sick every time you eat and have had limited success with more relaxed elimination diets like the Paleo diet, low FODMAP, or even an elemental diet “fast”, a meat-based diet may not be such a bad idea in the short-term. 

While supplementing with vitamins is not a great idea for getting your daily nutrients for long periods of time, if you can’t seem to get organ meats down, you may want to consider a multivitamin and/or B complex. As with any elimination diet, give it a shot for 3–4 weeks to see if your symptoms resolve or if you’re seeing progress with your other wellness goals. You should see some movement at this point, and if you’re not, it might be time to incorporate other gut-healing therapeutics, like probiotic supplements. 

Whichever elimination diet you choose, the final goal is always to give you a healthy life where you can enjoy a varied, whole-foods, and healthy diet. As with any diet, if you don’t feel great while you’re on it — whether that be for 1 month or 2 years — it’s probably not the right one for you. In other words, the diet that’s best for you is the diet that you feel best on.

Finding Merit in the Carnivore Diet  

The carnivore diet is an animal-based, plant-eliminating diet that may offer similar benefits to the keto diet, including better brain, heart, and immune health. While the research is scanty, there is a lot of anecdotal evidence to back it up. When done correctly, there appears to be a low risk of nutrient deficiencies and other adverse health outcomes. 

However, the reality is that no matter how beneficial or safe it is (though we don’t really know), its extremist nature is just too far out of reach for most people. Adopting a keto diet, or using the carnivore diet as a short-term plan for healing is way more realistic for most people who can’t tolerate other types of elimination diets. 

For help with finding the right diet or any of your health concerns, reach out to us at Ruscio Institute for Functional Health so we can assist with your needs. 

The Ruscio Institute has developed a range of high-quality formulations to help our patients and audience. If you’re interested in learning more about these products, please click here. Note that there are many other options available, and we encourage you to research which products may be right for you.

➕ References
  1. Lennerz BS, Mey JT, Henn OH, Ludwig DS. Behavioral Characteristics and Self-Reported Health Status among 2029 Adults Consuming a “Carnivore Diet”. Curr Dev Nutr. 2021 Dec;5(12):nzab133. DOI: 10.1093/cdn/nzab133. PMID: 34934897. PMCID: PMC8684475.
  2. O’Hearn A. Can a carnivore diet provide all essential nutrients? Curr Opin Endocrinol Diabetes Obes. 2020 Oct;27(5):312–6. DOI: 10.1097/MED.0000000000000576. PMID: 32833688.
  3. MCCLELLAN W, Du E. XLV. PROLONGED MEAT DIETS WITH A STUDY OF KIDNEY FUNCTION AND KETOSIS.*. https://www.jbc.org/article/S0021-9258(18)76842-7/pdf
  4. Masood W, Annamaraju P, Uppaluri KR. Ketogenic Diet. In: StatPearls. Treasure Island (FL): StatPearls Publishing; 2022. PMID: 29763005.
  5. Esposito T, Lobaccaro JM, Esposito MG, Monda V, Messina A, Paolisso G, et al. Effects of low-carbohydrate diet therapy in overweight subjects with autoimmune thyroiditis: possible synergism with ChREBP. Drug Des Devel Ther. 2016 Sep 14;10:2939–46. DOI: 10.2147/DDDT.S106440. PMID: 27695291. PMCID: PMC5028075.
  6. Vogtschmidt YD, Raben A, Faber I, de Wilde C, Lovegrove JA, Givens DI, et al. Is protein the forgotten ingredient: Effects of higher compared to lower protein diets on cardiometabolic risk factors. A systematic review and meta-analysis of randomised controlled trials. Atherosclerosis. 2021 Jul;328:124–35. DOI: 10.1016/j.atherosclerosis.2021.05.011. PMID: 34120735.
  7. Paoli A, Mancin L, Bianco A, Thomas E, Mota JF, Piccini F. Ketogenic diet and microbiota: friends or enemies? Genes (Basel). 2019 Jul 15;10(7). DOI: 10.3390/genes10070534. PMID: 31311141. PMCID: PMC6678592.

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