Trending diets seem to come and go, with the latest fad diet becoming flavour of the month. One of these trending diets is the carnivore diet, also known as the all-meat diet.
True to its name, the carnivore diet implies that you only eat meat and other animal products for every meal. For those who love to eat meat, the carnivore diet seems to be just the ticket, as you only eat meat, fish, eggs, and some other animal products. Aiming for zero carbs per day, even fruit and vegetables are excluded.
The carnivore diet originated from the controversial belief that our ancestors ate mostly meat and fish, and that the modern high-carb diets result in today’s high rates of chronic diseases. However, little is known about the health effects and tolerability of this diet.
Many trending diets are based on elements of truth, but not always the whole truth. Does the carnivore diet fall into this category?
What is the carnivore diet all about?
The carnivore diet is a meal plan in line with the way our hunter gatherer ancestors ate, doing away with the modern eating habits, such as high-carb foods. Our ancestors survived without agriculture as we know it, there being no fields of grains or vegetables, and fruits were scarce.
In the strictest version of the carnivore diet all plant foods and carbs are excluded, consuming only animal-based foods and water, as no tea, coffee, or any other drinks are allowed.
The mainstay of the carnivore diet is meat from ruminants, which are four-legged mammals that get their nutrients from plant-based foods, such as cows and sheep. Their digestive systems ferment their plant-based foods in a superior way compared to humans, which allows them to extract all their nutrients from plants. Advocates of the carnivore diet claims that humans are not well equipped to extract nutrients from plants and are better equipped to extract nutrients from animals. They also claim there is no such thing as essential carbohydrates.
Animal products allowed on the carnivore diet are beef, lamb, pork, chicken, turkey, organ meats (such as liver and kidneys), fatty fish (such as salmon, mackerel, cod, herring, oysters, sardines, anchovies, and even caviar), eggs, and small amounts of low-lactose dairy products, such as butter and hard cheese. Fatty cuts of meat supply daily energy needs, with a fatty steak viewed as the most nutritionally complete food to eat, as it has the best protein to fat ratio and nutrient density.
Heavily processed meats are excluded from the diet, such as bacon, sausage, pastrami, and pepperoni, as they are loaded with additives, nitrates, nitrites, sodium, and even sugar.
Claimed benefits of the carnivore diet
The carnivore diet is claimed to aid weight loss and blood sugar regulation as the major health benefits, while claiming that high-carb foods are the cause of chronic diseases.
A number of nutritional benefits are linked to the carnivore diet. Meat is a good source of high-quality protein, vitamins B6 and B12, iron, zinc, vitamin D, and selenium. Fish is a good source of high-quality protein, omega-3 fatty acids, iodine, vitamin D, and selenium, while dairy foods also contain high-quality protein, as well as calcium, B vitamins, and iodine. The humble egg is another source of high-quality protein, as well as vitamins (A, D, B12 and other B vitamins such as folate and choline) and minerals and trace elements, such as phosphorus, iodine, and selenium. Eggs also contain omega-3 fatty acids and all nine essential amino acids. (One egg contains only 74 calories, with 6 grams of high-quality protein and 5 grams of fat.)
Controlled studies on the long-term effects of the carnivore diet are lacking and known information about the effects are mostly from testimonials from carnivore diet consumers.
A social media-based survey, conducted by a team of researchers at Harvard University on 2029 adult participants who have been on the carnivore diet for 6 months or longer, reported in 2021 that participants expressed high satisfaction with this eating pattern, as well as having perceived good health status.
Motivation to lose weight was the main reason for the participants to go on this diet, and they reported substantial BMI reduction and improvements in physical and mental well-being, overall health, and chronic medical conditions, especially diabetes.
The participants, who self-reported the data used in the survey, showed a preference for fatty cuts of meat, which indicates a high fat intake. The lack of glucose from carbs as fuel for energy means that the body instead uses fat as fuel for energy. The macronutrient composition of the carnivore diet would probably be comparable to other very low carbohydrate diets, such as the ketogenic type of diets. Other studies have shown that high-protein and low-carb diets also promote weight loss, indicating that complete elimination of carbs is not necessary to lose weight.
Other potential health benefits of the carnivore diet include reported improvements in allergic conditions or inflammatory conditions. (Which may be due to some food allergies and sensitivities that are predominantly related to plant foods.)
As a no-carb diet excludes refined carbs and sugary foods, blood sugar regulation with the carnivore diet eliminates the blood sugar spikes associated with a high-carb diet. Participants in the survey with diabetes reported improvements in blood sugar control and a reduction in medication required to control diabetes.
Downsides of the carnivore diet
When entire food groups are omitted from the diet, there are bound to be consequences. The most obvious shortcoming is the elimination of highly nutritious foods such as fruits, vegetables, whole grains, and legumes that would normally provide beneficial vitamins and minerals.
The lack of plant fiber in the carnivore diet may have a detrimental effect on the proper balance of bacteria in the gut, which may increase the risk for gut inflammation. Increased dietary fiber is globally associated with lower risks of cardiovascular disease, type 2 diabetes, and colorectal cancer.
Although the absence of carbs contributes to the weight loss associated with the carnivore diet, many carbs are loaded with fiber, vitamins, and minerals. Unhealthy processed or refined carbs should, however, be avoided, as the best carbs are those that most closely resemble how they occur in nature.
A major shortcoming is the lack of controlled scientific studies on the long-term effects of this way of eating, as the current sources of information rely on testimonials and self-reported data about perceived health status and changes in health since starting the diet. Self-reporting data surveys should be interpreted cautiously as it excludes the ability to check the accuracy of the health information submitted by the respondents. No validated instruments were available in these self-reporting studies, as diet, nutrient status, or health-related outcomes were not objectively assessed. Self-reported data are also prone to recall and reporting bias.
Animal foods can be high in saturated fat and cholesterol. The lack of research on the long-term health benefits of the carnivore diet means the effects of consuming such high levels of saturated fat and cholesterol are unknown.
Conclusion:
While the carnivore diet is extremely restrictive (consisting entirely of meat, fish, eggs, and small amounts of low-lactose diary) with no reliable research to back up its claimed benefits, testimonials and self-reported studies have shown that people who followed this diet for six months or longer were highly satisfied with the weight-loss results and were generally feeling healthier.
Eating a balanced diet, which contains a variety of healthy foods from several food groups, would probably be more sustainable and provide more health benefits long-term. The most highly regarded example of a healthy balanced diet is the Mediterranean diet, which has repeatedly received accolades as the best diet overall.
The claims that the carnivore diet best resembles the way our ancient forefathers used to eat, mostly meat and fish, is refuted by biological anthropologists, as the anatomy of our brains, teeth, and intestines show that we evolved as highly flexible omnivores, who can adapt to live on both animal and plant foods.
References:
Behavioral characteristics and self-reported health status among 2029 adults consuming a “Carnivore diet”. Published December 2021 in the journal Current Developments in Nutrition. PubMed Central. National Centre for Biotechnology Information. US National Library for Medicine. National Institutes of Health. USA. (www.ncbi.nlm.nih.gov)
All you need to know about the carnivore (all-meat) diet. Information updated 13 March 2023. Healthline. (www.healthine.com)
Carnivore diet meal plan. Published online. Carnivore Diet Coach. (thecarnivoredietcoach.com)
The carnivore diet: Can you have too much meat? Published 1 July 2021. Cleveland Clinic. USA. (A nonprofit multi-specialty medical centre that integrates clinical and hospital care with research and education.) (www.clevelandclinic.org)
The carnivore diet: What eating only meat does to your health, a nutritionist explains. Published 5 December 2022. BBC Science Focus. (www.sciencefocus.com)
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