Food Freedom Friday Edition 269 - Going Carnivore

When talking about a carnivore-type diet, people often wonder is others are really only eating meat, and expecting to be healthy?

It might seem like another fad diet geared at grabbing attention more than anything. After all, despite the many differences of various popular diets, the one thing almost everyone seems to agree upon is that eating vegetables is good for you.

Not anymore.

Is there research on a carnivore diet? Is it a thing?

To be upfront: no, not really. Carnivore is so new (and so unusual) that nobody has studied it yet. Most of the claims about carnivore are speculative, or are based on personal experiences.  

That said, there is a fair amount of research on aspects of carnivore (just not the diet itself), and enough people report major success on a carnivore diet (along with individual blood work and lab testing that they make public) that carnivore is worth exploring. The carnivore diet does, however, deserve some due consideration whilst addressing some common concerns and exploring the possible reasons it seems to be working so well for so many..  

The Benefits Of A Carnivore Diet

There are a few aspects to carnivore that may explain why some people do so well on it. 

·       Ketosis. Eating only meat will put you into ketosis, which is well-established as a good way to lose weight and decrease inflammation. Ketosis also suppresses hunger signaling, which could explain why people report more satiation and fewer cravings on carnivore.

·       Higher testosterone and lower estrogen. Eating more fat and less fiber increases testosterone. Higher testosterone also increases muscle gain and accelerates fat loss. 

·       Decreased inflammation. A high-fat, low-carb diet decreases inflammation and improves blood lipids more than a high-carb, low-fat diet does.

·       Better digestion. A zero-fiber diet reverses constipation and reduces or eliminates gas and bloating entirely.

·       Avoiding food sensitivities. Carnivore is, by definition, an elimination diet. If you have sensitivities to certain foods, you may feel better on carnivore because you cut those foods out (unless you’re sensitive to meat, in which case carnivore will be a disaster).

It’s worth mentioning that these studies were not done using carnivore diets but rather keto diets or high-fat, low-carb diets, which means the results might not necessarily apply to a carnivore diet. That said, the study findings seem to line up nicely with common benefits people report on carnivore, namely, fat loss, decreased inflammation, fewer cravings, more energy, higher testosterone, muscle gain, and more.

Common Carnivore Diet Concerns 

Nutrients In Meat

Meat alone will not meet your recommended daily intake (RDI) for many micronutrients. Meat is not a good source of manganese, folate, vitamin K1, and a variety of other nutrients.

However, a fair number of long-term carnivores (a year or more) report blood work that shows no nutrient deficiencies and no symptoms of nutrient deficiencies either.

A popular explanation in the zero-carb community is that your vitamin needs change on a carnivore diet and there is research to back that theory. Micronutrient needs can shift according to metabolism. It makes sense that your body would run differently on a carnivore diet than it does on a high-carb diet, or even a standard ketogenic diet.

As an example, the body uses a large portion of dietary vitamin A to metabolize carbohydrates, and if carbohydrates are avoided, vitamin A requirements may decrease.

That said, there isn’t enough research on changing micronutrient needs to say definitively whether carnivore will provide all the micronutrients you need. If you decide to follow a carnivore diet, it is recommended to get micronutrient blood tests for the first few months, to make sure your nutrient profile is sufficient. 

Vitamin C In Meat

A related concern is that carnivore will cause scurvy from lack of vitamin C. Humans are unable to make vitamin C, it needs to be obtained from the diet. 18th-century sailors lost teeth to scurvy after months of surviving on nothing but dried meat and grains.

It is worth noting, though, that scurvy-ridden sailors were eating dried meat. Vitamin C is water-soluble, and drying out meat would remove any vitamin C that was present in fresh beef.

Surprisingly, fresh beef contains vitamin C -- about 16 mcg/g in grain-fed meat and 25 mcg/g in grass-fed meat.

That is a small amount of vitamin C, but it could be enough. Many have eaten nothing but beef, salt, and water for well over a year without developing scurvy, symptoms of which should show up within 3 months of starting the diet. The theory is that your vitamin C needs decrease when you cut vegetables out of your diet, and that the little bit in fresh beef is enough to keep you scurvy-free, as long as you don’t cook the vitamin C out by eating your meat well-done.

Some interesting research on this idea includes people on a  ketogenic diet who had higher vitamin C levels than people who went on a moderate-carb diet, despite the fact that, when getting only 4% of calories from carbohydrates, it’s difficult to consume large amounts of vitamin C. It is possible that very-low-carb diets decrease your vitamin C needs. 

Meat And Heart Disease

Eating nothing but meat means getting several times the recommended daily intake for saturated fat, and saturated fat intake is infamous as a risk factor for heart disease. Should you be worried about all that saturated fat?

In my opinion, no. I’ve written about saturated fat before. In a nutshell, I think the studies correlating saturated fat with heart disease are based on weak evidence and are unconvincing.

Recent research has found that saturated fat intake actually improved blood lipid profile and heart disease risk in people who followed a low-sugar, low-carb diet for a year (people on a low-sugar, low-fat diet saw similar improvements).

Saturated fat is probably not a concern, especially in the context of a low-carb diet.

Meat, Fiber And Cancer

A variety of epidemiological studies have found that red meat correlates with an increased risk of colon cancer, particularly in developed countries.

However, no such correlation exists in Asia, including in regions where people, on average, eat far more red meat than Westerners do. It is possible that the correlation is due to confounding factors other than meat intake (like PUFA consumption).

A high-fiber diets also seem to correlate with decreased risk of colorectal and colon cancer, while a low-fiber diet correlates with increased risk. Do you need fiber to keep your colon healthy?

Evidence is divided when it comes to the need for and benefit of fiber. There are a few cases for eliminating fiber intake:

·       Avoiding constipation, gas, and bloating. Zero fiber intake completely eliminates gas and bloating and reverses constipation, which suggests that carnivore could improve your digestion, especially if you’re prone to constipation or bloating.

·       Decreased risk of diverticulosis/diverticulitis. A low-fiber diet also correlates with a lower risk of developing diverticulosis -- a very common condition where sacs form along your colon due to weakness in your intestinal walls (note that this is correlation, not causation).

·       Decreased intestinal stress. Fiber is also an intestinal irritant -- because you can’t digest it, it passes through your intestines intact, physically rubbing against your gut lining, causing micro abrasions. That may not be an issue for the average person, but if your gut is sensitive (if you have IBS, for example), fiber can cause diarrhea and severe bloating and pain.

Alternatively, there is compelling evidence that fiber is good for you. Fiber feeds good gut bacteria, helping them crowd out damaging microbes in your gut, and those bacteria turn fiber into short-chain fatty acids that improve overall intestinal health and decrease gut inflammation. Low-fiber diets, on the other hand, can promote the growth of damaging gut bacteria.

It is hard to say whether following a low to no fiber diet, like the carnivore diet, is good or bad for you digestive tract. The effect may vary from person to person -- but if you find you have digestive issues after ~4 weeks of letting your gut adapt to carnivore, you may want to add some variety back into your diet.

Evolution And Eating Only Meat

There is a hypothesis that humans evolved to eat plants out of necessity, because it was sometimes challenging for ancient man to access meat. Meat is a denser source of nutrition and the body does prefer it as a food source, but it was not always available, so humans adapted by learning to digest plants as well to ensure survival, despite the fact that plants are a less-optimal and less bioavailable nutrient source.

There is actually some research to support this hypothesis. Humans absorb a variety of nutrients better when they come from animal sources. Iron, zinc, vitamin A, protein, and vitamin B12 are all nutrients that are better absorbed when obtained from meat. The same is true of omega-3s. DHA and EPA animal-based omega-3s are readily and easily absorbed, whilst only about 6% of plant-based omega-3s are so readily available as they need to be converted into, and we have to convert them into animal form. 

Furthermore, plants contain antinutrients that actively block nutrient absorption, so while plants may have higher raw levels of many vitamins and minerals, your body might not actually be able to access them.

Today, though, there is a steady access to a wide variety of edible plants, and cooking destroys most of those plants’ antinutrients. That means you can readily absorb the vitamins and minerals in vegetables, fruits, and even well-prepared seeds, grains and legumes. Even if all-meat diets were evolutionarily ideal for in the past, this does not necessarily imply carnivore is the healthiest diet today, considering the exceptional access to a variety of foods.

This is just scratching the surface of the link between evolution and carnivory. It’s a fascinating topic that requires a much greater in-depth discussion.

Getting Started

If you are curious about whether following a carnivore type diet will be beneficial for you and you are not already fat adapted (or have not been following a low carb protocol), you can expect many of the initial, adaptation-related side effects that come with a low carbohydrate or ketogenic diet: 

·       Keto flu, where you feel weak and tired as your body switches from burning carbs to burning fat for fuel

·       Digestive changes such as diarrhea as your digestive system adjusts to a zero-carb diet

·       Nausea from increasing your fat intake

These side effects should be temporary, and generally go away after two to four weeks on a carnivore diet. If they persist, you may need to make modifications or a purely carnivore may not be for you. You may also need to work on some gut healing protocols to effectively digest and absorb all the nutrients you are now consuming

If you are going to try carnivore, I suggest, as with any dietary change, to check in with a trusted and knowledgeable practitioner and possibly getting blood work done to ensure your micronutrients are where they should be. Pay careful attention to how you feel, too; if you’re having any strange symptoms, you may want or need to make certain adjustments and modifications for your unique needs.