Pros and cons of the carnivore diet (2024)

Plant-based diets such as the Mediterranean diet have long been favoured as the healthiest and most sustainable way to promote longevity and wellness. However, the quietly emerging carnivore is turning this well-established paradigm on its head.

The carnivore diet is an eating regimen that prohibits plant consumption and is inclusive of only animal products, permitting only meat and water in its most extreme form. Despite its severely restrictive nature the perceived benefits have allowed the diet to grow in popularity. While merely anecdotal, advocates for the diet report a range of benefits including weight loss and the repair of gastrointestinal conditions.

Standard practice expects healthcare professionals to be familiar with emerging health trends and as such, pharmacists should be able to provide sound and scientifically supported advice to patients inquiring about the benefits and implications of the carnivore diet.

Scientific Explanation For Benefits

WEIGHT LOSS

The carnivore diet may yield weight loss but this is most likely related to a reduction in caloric intake and not necessarily attributed specifically to the exclusive consumption of meat. Although the diet doesn’t call for any intentional caloric deficit, animal protein is highly satiating and is likely to lead to an unintentional decrease in caloric intake. Furthermore, unlike simple carbohydrates it is near impossible to mindlessly consume meat; consider the ease of finishing off a bag of potato chips versus overconsuming a plate of chicken breast

IMPROVE GASTROINTESTINAL ISSUES

There are anecdotal reports that through improving gut health, the carnivore diet is able to relieve symptoms and potentially cure chronic conditions such as metabolic disease, autoimmune conditions, neurodegenerative disorders and cardiovascular disease.

Although it is certainly plausible that an improvement in gut health can be protective against disease, it would be a stretch to claim this outcome can be achieved by following the carnivore diet. The available evidence suggests that microbial diversity is the most reliable indicator of gut health and microbial diversity may only be achieved through the consumption of fibre, which is not permitted in the carnivore diet.

It is more likely that the purported benefits are as a result of the highly restrictive nature of the carnivore diet making it comparable to the initial stages of an elimination diet. The goal of an elimination diet is to reduce gut inflammation and relieve clinical symptoms by removing foods and chemicals that the patient may be sensitive to or allergic to. Although unintentional, the carnivore diet mimics this process and it is likely that through consuming only meat products food compounds that previously triggered physical symptoms were removed, making it appear as though gut health has been restored.

Nutritional Concerns Associated With Carnivore Diet

LACK OF VARIETY

In order to promote health and reduce the risk of disease there is a shared understanding across the literature that a diverse dietary pattern is essential. Diversity can be achieved by consuming foods from each of the five food groups, which are characterised based on the similar nutrients provided by each group.

Animal meat is considered to be a part of the protein food group, providing essential nutrients such as amino acids, fats, and valuable vitamins and minerals including iron, zinc and most B vitamins. For less restrictive followers, dairy products can provide additional protein along with beneficial vitamins and minerals such as calcium, vitamin D, and some B vitamins. However, the elimination of fruits, vegetables and grains puts patients at risk of a deficiency in an array of essential nutrients including Vitamin A, Vitamin C, and certain B vitamins such as folate and biotin, Vitamin E, Potassium, and Magnesium.

Some additional vitamins and minerals can be obtained through the consumption of organ meats such as liver, kidney, sweetbreads, lungs, tongue, heart, and brain. However, the preparation and consumption of organ meats is foreign for the majority of the population and in many cases, the food source needs to be consumed raw, which can have major safety implications if the organs are not carefully sourced and prepared.

There is also the presence of less desirable nutrients to consider, specifically saturated fat. It is well-established that eating excessive saturated fat can raise cholesterol levels in the blood, which increases the risk of cardiovascular disease.

SEVERELY RESTRICTED FIBRE INTAKE

There is a significant body of research that attributes the beneficial effects of diet fibre to the role it has in promoting a diverse microbiome. A fibre-rich diet promotes the growth of beneficial microbes that ferment fibre into byproducts, notably the short-chain fatty acid butyrate which provides nourishment to the epithelial cells and reinforces the integrity of the mucus barrier.

However, the resident microbiota can be altered depending on the fuel sources they are provided. With a deficiency in dietary fibre, fibre-reliant microbes will deplete and those that remain will turn to mucus glycoproteins as their nutrient source, negatively impacting the microbiota diversity and challenging the integrity of the mucus barrier.8 Alternatively, a diet high in animal protein encourages an overgrowth of proteolytic bacteria that break down undigested protein. Through fermentation, undigested protein can produce small amounts of beneficial SCFA, but mostly results in the substantial production of potentially deleterious metabolic products including branch-chained fatty acids, ammonia, amines, hydrogen sulfide, phenols, and indoles. These metabolic products have been shown to increase inflammatory response and tissue permeability while also being implicated in the development of metabolic diseases and cancers.

POTENTIALLY CARCINOGENIC

While the carcinogenic potential of a diet high in animal meat is well-documented throughout the literature, the mechanism is yet to be definitely defined. What is known is that the intake of animal meat leads to an elevated presence of heterocyclic amines (HCAs), nitrosamines and N-nitroso compounds (NOCs); all of which are known carcinogens.

HCAs are chemicals formed when animal meat is cooked using high-temperature methods, with more HCAs present when the meat is cooked for a long time (i.e. well-done meat). In laboratory experiments, HCAs have been found to damage DNA which may increase the risk of cancer.

Both nitrosamines and NOCs are formed by a reaction between nitrates and nitrites and certain amines. Nitrates and nitrites are similar chemical compounds that naturally occur in an abundance of plant foods and are added to processed meats as a preservative. While nitrates and nitrite compounds themselves are not carcinogenic, when they are combined with amines nitrosamines and NOC compounds are able to be formed. Studies have also shown that the formation of NOCs can be further catalysed by the presence of heme iron. Since animal protein is rich in both amines and heme iron, there is good quality evidence to demonstrate that the consumption of animal meat is likely to be carcinogenic to humans. Interestingly, the formation of carcinogenic compounds can be antagonized by inhibitors found in fruits and vegetables.

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