This post was written by Irene Mejia, RD and Sports Nutrition Specialist. 

In the past few decades, many low-carb diets have emerged, such as Atkins or the “keto diet”. 

But in the late 2010’s, a new type of diet started gaining attention, especially due to its controversial dietary approach: the carnivore diet. 

This diet focuses exclusively on consuming animal products, and it limits or completely eliminates carbohydrates. 

This article aims to provide an evidence-based analysis of the carnivore diet, examining its definition, origins, features, pros, and cons. Additionally, it will address some frequently asked questions about the topic.

The Carnivore Diet Basics

The Origins and Definition

While the concept of only eating animal products may have been brought to light by other people in the past, the official “Carnivore Diet” was developed by former American orthopedic doctor Shawn Baker in 2019, after publishing a book called “The Carnivore Diet”.

It is rooted in the belief that humans have evolved as carnivorous beings, adapted to thrive on a diet primarily consisting of meat. 

The author claims that he was experiencing several health issues which were not resolving, but after a two-month elimination diet of only meat, water and salt, most of his symptoms were gone (1).

In his book, he specifies that the basics of the carnivore diet are as follows (1):

• Red meat and water are the basis 
• Fat % should be 50-80% most of the time
• Focus on ruminant red meat (beef, lamb, goat, wild game…)
• Then, complement diet with seafood/poultry, organs
• Dairy products in moderation
• Seasoning as tolerated
• Limit alcohol, coffee, tea, and drink plenty of water

Since this diet was developed by the author, there are no current official guidelines to follow other than the ones mentioned in his book (2). 

However, the author does indicate that “he’s not dogmatic about what people eat”, so even if he does provide some recommendations, those who decide to follow this diet can choose the animal products they desire. 

Carbohydrates, Macronutrients, and the Ketogenic Diet

As you can see from the previous section, this diet completely eliminates carbohydrates. 

It excludes all other foods, including vegetables, fruits, grains, legumes, nuts, and seeds, and in some instances, some decide to limit dairy products as well.

Another feature is that in this diet there is no specific macronutrient breakdown (for example, 50% fat, 50% protein…). Also, the author does not emphasize in counting calories, but focusing on the food quality instead. 

This is the main difference between the carnivore diet and the ketogenic diet. The ketogenic diet has a strict macronutrient breakdown (usually ~70-80% fat, 10-20% protein, 5-10% carbohydrate) because the goal is to be on ketosis, and it allows for some carbohydrates (3). 

On that note, being on a carnivore diet may not put you on ketosis, especially if you consume a lot more protein than fat (especially if you eat many lean proteins) – this is because your body can create glucose from protein (4). 

Pros of the Carnivore Diet

Now that we discussed the basics of the carnivore diet, let’s cover the pros and cons, starting with the potential benefits.

Proponents of the carnivore diet suggest several benefits, although it is worth noting that due to the limited research, many of these benefits are based on anecdotal evidence.

Improved Medical Conditions and Energy Levels

This article shows the results of researchers who surveyed ~2,000 people committed to the carnivore diet. 

However, we must keep in mind that this study has many limitations, especially that it was done using self-reported data from a social media survey. Nonetheless, it is still worth analyzing the results (5).

The participants in the study self-reported several benefits, such as: 

• Improvements in their chronic medical conditions, general health, and well-being
• Feeling more energetic, sleeping better, focusing more, and having better mental clarity

Other people have self-reported improved blood sugar control, and relief from certain digestive issues. 

Also, some individuals with autoimmune conditions have reported symptoms improvement while following this diet, such as Mikhaila Peterson, a strong proponent of the carnivore diet (6).

Weight Loss 

One of the most common self-reported benefits of this diet is weight loss. This could be due to a few reasons:

• Water-losses: carbohydrates are stored as glycogen in our muscles and liver. Each glycogen molecule is stored with ~3 grams of water (6). When the glycogen storages run out, a lot of water weight is lost fairly quickly.

• Reduced calorie consumption: as opposed to carbohydrates, proteins are very satiating, and this diet is very high in protein. Therefore, we may feel fuller faster, and stay satiated for longer (7). 

• Thermogenic effect: your body uses a significant amount of calories to break down the proteins we eat (~30% of calories) as opposed to carbohydrates or fat. (7). 

Nutrient Bioavailability & Meal Simplicity

Animal proteins are considered “complete proteins” since they contain all of the essential amino acids, and they are also more bioavailable than most plant-proteins. (8).

Plant-proteins are usually surrounded by other things such as fibers, which makes it harder for your body to utilize it. You can still obtain all of the amino acids on a plant-based diet, but you need to “mix-and-match” different foods (8).

Therefore, you could have simpler meals on a carnivore diet and cut down cooking time because: 

• The carnivore diet only allows a selected list of food items
• Proteins are more satiating, so you would get full quicker
• You could eat smaller quantities of food since the animal proteins are more bioavailable

Cons of the Carnivore Diet

Safety

As mentioned before, this diet was published by former American orthopedic doctor Shawn Baker in 2019.

In the research world, 2019 is very, very recent. For comparison, the ketogenic diet has been studied since the 1920s. Thus, evidenced-based research about the carnivore diet is very limited so far.

According to Harvard, “there is little data on this way of eating, but historic reports from Arctic and nomadic populations suggest that it may be possible to thrive on an animal-based diet in the long-term” (5).

But due to the limited research – it is not possible to determine with certainty its safety short or long-term. 

Nutrient Deficiencies

One primary concern is the risk of nutritional deficiencies (or in some cases, nutrient toxicity) due to the exclusion of plant-based foods, which provide essential vitamins, minerals, and antioxidants. 

Some foods such as beef liver are very rich in nutrients, which could account for some of the possible nutrient deficiencies on this diet. But we must keep in mind that foods like beef liver can be very high in fat-soluble vitamins (especially vitamin A). 

As opposed to water-soluble vitamins, the body cannot get rid of excess fat-soluble vitamins, so it stores them. Therefore, toxicity could be a risk, especially if eaten in large quantities (9).

FAQ

1. Do I need fiber?

This is a controversial topic – the short answer is no, but it is not as simple as that. A nutrient is something that we couldn’t survive without, or that we could develop a disease if we don’t consume it.

Therefore, technically we don’t NEED fiber. In other words, we would not die from not eating it. 

Research still shows it has many benefits, including the prevention of many diseases, can help reduce cholesterol levels, and it can help with intestinal regularity.

2. Aren’t polyunsaturated fats (PUFAs) better than saturated fats? 

Animal proteins tend to be high in saturated fats – and current dietary guidelines suggest that we should limit saturated fats and replace them with PUFAs to improve our lipid panel (10). 

There are two main types of PUFAs, omega-6 and omega-3s. Foods rich in omega-6s include vegetable oils, and foods rich in omega-3s include fatty fish, walnuts, etc. 

So far, it seems that replacing them with omega-6s is not as beneficial, but research strongly suggests that omega-3s have many health benefits, especially on cardiovascular disease (10). Therefore, including omega-3s in the diet could be a good alternative. 

3. Can I drink alcohol on a carnivore diet?

The carnivore diet primarily focuses on animal-based foods, and alcoholic beverages are not part of the diet plan. Also, some of these drinks contain carbohydrates, so it goes against the principles of the diet. 

Here is an article detailing the grams of carbohydrates in common alcoholic beverages. 

Conclusion

The carnivore diet, a highly restrictive dietary approach that emphasizes consuming only animal products, has gained attention in recent years. 

This diet is very recent – so there is very little research about it. 

Anecdotal evidence and some research suggest some potential benefits, such as weight loss, nutrient bioavailability, meal simplicity, and improvements of certain chronic diseases.

However, it is crucial to consider the associated drawbacks, including the risk of nutritional deficiencies or toxicity, and the lack of information about potential long-term effects.

Before embarking on the carnivore diet, it is advisable to consult with a healthcare professional or registered dietitian to ensure adequate nutrient intake, monitor health markers, and address individual needs. 

References

1. https://www.doctorkiltz.com/shawn-baker-carnivore-diet/
2. https://www.barnesandnoble.com/w/the-carnivore-diet-shawn-baker/1129154115
3. https://exerscifit.com/ketogenic-diet/
4. https://www.verywellfit.com/gluconeogenesis-2242007#:~:text=Gluconeogenesis%20is%20the%20process%20of,certain%20amino%20acids%20(protein).
5. https://chgeharvard.org/harvard-study-on-the-carnivore-diet/#:~:text=So%2C%20how%20were%20people%20feeling,better%20mental%20clarity%20and%20focus
6. https://pubmed.ncbi.nlm.nih.gov/25911631/#:~:text=Conclusions%3A%20Our%20findings%20agree%20with,storage%20not%20bound%20to%20glycogen.
7. https://pubmed.ncbi.nlm.nih.gov/18469287/
8. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6723444/
9. https://www.webmd.com/diet/liver-good-for-you#:~:text=It’s%20possible%2C%20and%20dangerous%2C%20to,serving%20of%20liver%20per%20week.
10. https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/fats-and-cholesterol/types-of-fat/