The all-meat carnivore diet is so controversial that advocates and critics haven\u2019t stopped arguing for years. It\u2019s easy to get confused by what appears to be conflicting information. Let\u2019s break it down and take a closer look at these arguments – and the science behind them.<\/p>\n
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You may have landed here from our previous article on nutrient deficiencies<\/a> in the carnivore diet<\/a>, which details a list of potentially dangerous deficiencies that can result from the diet.<\/p>\n If so, then you know the carnivore diet is exactly what it sounds like: a diet plan that only includes meat<\/strong>. If you haven\u2019t read our nutrient deficiency post, you might want to start there.<\/p>\n The diet is controversial. Its advocates claim that it improves brain function and stops autoimmunity and inflammation in its tracks. Critics point to potential deficiencies and a lack of well-powered research<\/strong> supporting such a radical diet. In the online carnivore and zero carb communities, the argument gets pretty heated. It can be hard to take a step back and think critically.<\/p>\n We\u2019d like to address some of the most common claims and arguments presented by carnivores. After all, it\u2019s important to do your research, to know all the facts, and to avoid dogma of any kind.<\/p>\n Within the zero carb community, the most common critique of the nutrient deficiency argument is that daily recommended intakes were calculated for people eating a Western diet. Critics insist that people eating a carnivore diet have different (they say lower) requirements for vitamins, minerals, and fiber.<\/p>\n No evidence supports this line of thought<\/strong>. In fact<\/strong>, carnivores may often need more than the recommended intake of antioxidant nutrients<\/strong>. Eating a lot of meat – especially if cooked at high temperatures – raises oxidative stress<\/a> [R<\/a>].<\/p>\n The recommended intakes may also be too low for some individuals, depending on their health and habits. Experts and researchers make these recommendation based quantities that will meet nutrient requirements in nearly all healthy people. These are called Recommended Dietary Allowances (RDA). If there\u2019s not enough evidence to come up with an RDA, Adequate Intake (AI) is used [R<\/a>, R<\/a>].<\/p>\n However, there are several issues with these values:<\/p>\n Look into the factors that apply to you to figure out if you may need more or less of any given nutrient. Such modifications will not dramatically differ from the recommended values, however. RDAs\/AIs are still your best rough bet, at least until individualized guidelines come out.<\/p>\n If you have your heart set on the carnivore diet, we strongly recommend working with a licensed nutritionist or a doctor to ensure that you don\u2019t seriously damage your health in the process.<\/strong><\/p>\n One study has investigated potassium<\/a> and sodium balance in athletes eating a low-carbohydrate, mostly meat diet based on the traditional diet of the Inuit. Meat often does not contain enough potassium to reach the daily recommended intake on its own [R<\/a>].<\/p>\n The participants of this study experienced an initial decline in blood potassium; levels stabilized after four weeks on the ketogenic \u201cInuit\u201d diet. Once these people had adapted to the ketogenic diet<\/a> (a process that took about 3-4 weeks), their potassium requirements appeared to decrease from 3.4 g per day to about 1.5 g per day<\/strong> [R<\/a>, R<\/a>].<\/p>\n Hopefully, researchers will conduct additional studies on other nutrients in the future. Until then, it\u2019s better to be safe and try to reach all of the nutrient recommendations<\/strong>. Work with a nutritionist to ensure that your diet is not deficient in important nutrients.<\/p>\n Some carnivores claim that the discussion of recommended intakes is largely nonsensical because food labels may not correctly report nutrient content. On the one hand, fair enough: the official nutrient content of various foods has been changing for decades; certain nutrients, such as fiber, are more difficult than others to measure [R<\/a>].<\/p>\n On the other hand, the USDA\u2019s National Food and Nutrient Analysis Program (NFNAP) exists precisely to prevent and correct such errors. <\/strong>This program, which has been operating since 1997, constantly updates and expands its data and methods. There is no guarantee that the current USDA data is absolutely correct, but it\u2019s the best data available [R<\/a>].<\/p>\n Some carnivores argue that nutrients are more easily absorbed from meat sources than from plant sources. In certain cases, this is true. Some nutrients that are more easily absorbed from meat<\/strong> include:<\/p>\n Some plant compounds<\/strong>, such as<\/strong> phytates<\/strong><\/a>, may decrease the absorption of iron and zinc<\/strong>, whereas high-protein foods increase zinc absorption. Retinol<\/a>, the active form of vitamin A<\/a>, is often available directly from meat, whereas plants contain carotenoids that must be converted to vitamin A in the body [R<\/a>, R<\/a>, R<\/a>].<\/p>\n Protein intake changes the chemistry of the digestive system and may affect nutrient uptake as well. High-protein diets encourage more acidity in the stomach<\/strong>, which in turn increases the absorption of some nutrients<\/strong>. Low-protein diets reduce the production and flow of bile<\/a>, which is important for absorbing fat-soluble vitamins (such as vitamins A, E, and D) [R<\/a>].<\/p>\n Plant-based foods can be more difficult to digest because of their sturdy cell walls. This means that your <\/strong>digestive enzymes<\/strong><\/a> can break meat down to release the nutrients with greater ease<\/strong>. Mincing meat additionally increases nutrient bioavailability [R<\/a>].<\/p>\n On the other hand, meat does not contain some vital nutrients, like vitamin C, that are required to maintain health<\/strong>. Read this post on nutrient deficiencies in the carnivore diet<\/a> for more.<\/p>\n A few popular diets (the carnivore diet included) are based on the idea that modern humans just aren\u2019t eating the appropriate foods for our evolutionary requirements.<\/p>\n There\u2019s a grain of truth to this argument: archaeological and genetic evidence suggests that early modern humans ate a fatty<\/strong>, protein-rich diet<\/strong> shortly before the advent of carbohydrate-rich agriculture [R<\/a>, R<\/a>, R<\/a>, R<\/a>].<\/p>\n However, there\u2019s a significant logical jump between \u201cearly modern humans ate a fatty, protein-rich diet\u201d and \u201chumans aren\u2019t adapted to eating plants.\u201d The first doesn\u2019t lead to the second. Let\u2019s break it down further.<\/p>\n Some people defend the carnivore diet with the claim that our ancestors ate diets of almost exclusively meat. Take care with these claims<\/strong>; some of them may be based on evidence about Homo neanderthalensis<\/em><\/strong>,<\/em> not Homo sapiens<\/em><\/strong>. These are two different species, and Neanderthal contributions to modern human DNA are very small (0% in African populations and up to 2% in Europeans and Asians) [R<\/a>, R<\/a>, R<\/a>].<\/p>\n Neanderthals were<\/strong>, for all intents and purposes<\/strong>, functional carnivores<\/strong>. Many researchers believe they relied heavily on mammoths as their primary food source and were probably the mammoth\u2019s most important predator [R<\/a>, R<\/a>].<\/p>\n However, even Neanderthals ate plant foods<\/strong>; archaeological evidence suggests that Neanderthals ate starchy roots and seeds. They may also have consumed plants as medicine [R<\/a>, R<\/a>, R<\/a>].<\/p>\n In short:<\/p>\n These facts say nothing about whether the carnivore diet is good or bad for any one<\/strong> person<\/strong>. They simply remind us not to make sweeping generalizations about what is \u201cappropriate\u201d based on inappropriate information.<\/p>\n This much is clear: humans are adapted to eat meat<\/strong>. Our large brains and ability to walk on two legs may be closely linked to increased meat intake and a need to carry meat, respectively [R<\/a>].<\/p>\n Our teeth and guts are appropriate for a mixed diet<\/strong>. Our molars are smaller and our front teeth and jaws are stronger than those of our plant-eating primate ancestors. Our digestive system shares traits with both herbivores and carnivores. We do not have the short, hyper-acidic gut of a true carnivore, nor the long fermenting colon of a true herbivore [R<\/a>, R<\/a>].<\/p>\n Humans are highly adaptable to our environments. Our bodies are extremely flexible, and most people have a lot of options for diet and good health. Some researchers argue that the phrase \u201cevolutionarily appropriate diet\u201d is meaningless<\/strong> because we evolved to eat almost anything<\/em> [R<\/a>].<\/p>\n Of course, that doesn\u2019t mean that a diet of \u201calmost anything\u201d will result in optimal – or even good – health.<\/p>\n There is no evidence that plant-based food negatively affects the health or physical performance of the average person in the general population<\/strong>.<\/p>\n In a study of endurance athletes, peak performance was not significantly different between vegetarian<\/a> and omnivorous groups. Obviously, this study says nothing about whether carnivores would have outperformed the others; however, it does show that eating only plants is no worse than eating plant- and animal-based foods together<\/strong> [R<\/a>].<\/p>\n Plant-based diets have been suspected of producing lower bone mineral density, especially in young, growing adults. This doesn\u2019t appear to be the case, either: when controlling for physical activity<\/strong>, obesity<\/strong>, and smoking<\/strong>, bone mineral density is not affected by a<\/strong> plant-based diet<\/strong><\/a> [R<\/a>].<\/p>\n Humans are adapted to eating meat<\/strong>. We are also adapted to eating plants<\/strong>. Our teeth and digestive systems are versatile and flexible; evolution has set us up to eat just about anything.<\/p>\n Some carnivores advocate eating fresh, raw or very lightly cooked meat to ensure that the nutrients inside aren\u2019t degraded or otherwise lost. Most notably, vitamin C<\/a> easily breaks down when heated. Many other nutrients<\/strong>, such as the B vitamins<\/strong>, are water-soluble and can<\/strong>, therefore<\/strong>, be lost with the juices<\/strong> [R<\/a>, R<\/a>].<\/p>\n Take care, however. There are plenty of arguments against eating meat raw.<\/p>\n If you choose to eat raw or lightly-cooked meat, be aware of the risk of bacterial contamination. Every physical step during meat processing <\/strong>(slaughter<\/strong>, cleaning<\/strong>, butchering<\/strong>) introduces new bacteria into an animal carcass<\/strong>. These include pathogens like Pseudomonas<\/em> species, Escherichia coli<\/em>, and Staphylococcus aureus<\/em> [R<\/a>].<\/p>\n Organic meat from healthy animals has no less pathogenic bacterial contamination than factory- or conventionally-farmed meat. However, antibiotic-resistant bacteria is much more common in meat from factory- or conventionally-farmed animals<\/strong> [R<\/a>, R<\/a>].<\/p>\n However, organic meat still contains potentially dangerous bacteria.<\/p>\n Bacteria aren\u2019t the only potential threat of raw meat. Parasites may be present in the muscles and organs of common livestock<\/strong>, fish<\/strong>, and game<\/strong>.<\/p>\n Raw beef liver may contain Toxocara canis<\/em>, a roundworm that typically infects dogs but can cause a dysregulated immune system and lesions in the liver and lungs of humans. Raw pork and pig liver (often consumed as sashimi in Japan) can carry tapeworms. Wild game meats like bear and boar may contain Trichinella<\/em> roundworms. Raw and undercooked salmon often contains Anisakis <\/em>roundworms that quickly produce food poisoning-like symptoms [R<\/a>, R<\/a>, R<\/a>, R<\/a>, R<\/a>].<\/p>\n Deep freezing for 3-4 weeks will kill many<\/strong>, but not all parasites<\/strong>. Some species of Trichinella<\/em> can survive being frozen for more than a year [R<\/a>].<\/p>\n There\u2019s good evidence that humans evolved (in the last million years, but before Neanderthals and modern humans diverged) to eat cooked food, rather than raw [R<\/a>, R<\/a>].<\/p>\n One reason for this adaptation is that cooked food has more available energy than raw food<\/strong>. The same cut of meat provides more energy cooked than raw [R<\/a>].<\/p>\n The medical consensus is that we need fiber to make sure we have healthy bowel movements and prevent constipation, and carnivores claim this isn\u2019t true.<\/p>\n That\u2019s not the only point of contention, however.<\/p>\n Strangely, reducing or eliminating fiber resolved chronic constipation, as well as the pain<\/a>, bloating, and bleeding associated with it, in two studies with a total of 779 participants [R<\/a>, R<\/a>].<\/p>\n In a study of 63 people with constipation of unknown cause, eliminating fiber completely reversed their symptoms [R<\/a>].<\/p>\n Phytates in high-fiber foods such as fruits<\/strong>, vegetables<\/strong>, and grains could potentially decrease the amount of<\/strong> magnesium<\/strong><\/a> absorbed in the gut<\/strong>. This may expose people who eat a lot of plant-based foods to developing magnesium deficiency, which in turn causes gastrointestinal symptoms, fatigue, and weakness [R<\/a>, R<\/a>].<\/p>\n On the other hand, many plant-based foods are rich enough in magnesium to make up for this effect<\/strong>. Spinach, nuts, and seeds (such as pumpkin seeds) are especially high in magnesium [R<\/a>, R<\/a>].<\/p>\n High protein intake may also improve magnesium absorption, but it doesn\u2019t seem to matter whether the proteins are animal- or meat-based [R<\/a>].<\/p>\n<\/a>Common Arguments from Carnivores<\/strong><\/span><\/h2>\n
<\/a>1) \u201cRecommended Intakes Were Developed for the Western Diet, Not a Carnivore Diet\u201d<\/strong><\/span><\/h3>\n
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<\/a>The Potassium Exception<\/strong><\/h4>\n
<\/a>Incorrect Food Labels<\/strong><\/h4>\n
<\/a>2) \u201cNutrients are More Bioavailable in Meat\u201d<\/strong><\/span><\/h3>\n
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<\/a>Protein and Nutrient Absorption<\/strong><\/h4>\n
<\/a>Nutrient Deficiencies<\/h4>\n
<\/a>3) \u201cHumans are Adapted to Eating Meat, Not Plants\u201d<\/strong><\/span><\/h3>\n
<\/a>The Neanderthal Question<\/strong><\/h4>\n
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<\/a>The Evolution of Omnivory<\/strong><\/h4>\n
<\/a>Plant Food and Performance<\/strong><\/h4>\n
<\/a>In Brief<\/strong><\/h4>\n
<\/a>4) \u201cFresh, Raw Meat has Everything We Need\u201d<\/strong><\/span><\/h3>\n
<\/a>Bacterial Contamination<\/strong><\/h4>\n
<\/a>Parasite Risk<\/strong><\/h4>\n
<\/a>The Genetics of Cooking<\/strong><\/h4>\n
<\/a>5) \u201cWe Don\u2019t Need Fiber to Stay Healthy\u201d<\/strong><\/span><\/h3>\n
<\/a>Stool Quality & Constipation<\/strong><\/h4>\n
<\/a>Magnesium Absorption<\/strong><\/h4>\n