The carnivore diet…should you do it? Have you heard of it?
The carnivore diet
So many people ask me about the carnivore diet, and I’m a little bit torn. There seem to be some benefits, clearly, but there are a lot of unknowns. I was introduced to the carnivore diet by several influencers on YouTube. You might have heard of them: Ken Berry, Shawn Baker, and Bart Kay – some very vocal folks. What do we really know about the carnivore diet, and how would you think critically and scientifically about it? Some people think back to the ancestral way of eating and claim that humans were designed to eat this way without vegetables, and I’m not really compelled to write home with that level of information. I need more than that. It may be that that’s true, but it could be that we evolved to need different nutrients today that might not have been provided in the past, different infections, etc.
The way I look at any kind of diet is: does it provide all of the nutrients that we think we need today? I say “think” because even new vitamins are being discovered and having new uses. So we use our best judgment. I think the carnivore diet, an animal-based diet with no vegetables, can fulfill the need for all of the essential nutrients. One of the things I was able to do was to ask people in the carnivore world to put together information about this approach. I asked Amber O’Hearn to write a paper on “Can a carnivore diet provide all essential nutrients?” It’s a scholarly view of what nutrients may be required and may or may be missing.
Of course, the classic comparison is that animals that are true carnivores really just eat other animals. And so, for those mammals, there really is everything you need in other animals. It’s very rare for a dog or a cat to want to eat grass, for example. When I look at the internal anatomy of different animals, it’s clear to me that the gastrointestinal tract of a human is more like that of a carnivore than of an herbivore. There is a great video that I learned a lot from by a gentleman named Barry Groves, called “Homo Carnivorous.” In this video, Barry makes the argument that humans should be carnivores. The most important part, I think, which is the internal anatomy, the gastrointestinal tract, is from 7:43 to 14:48, showing the comparative absorption of nutrients among different mammals. This was really striking and shocking to me. I’ve seen doctors talk about how cows can eat grass, so humans can too, but the internal anatomy of cows is totally different from humans, and even then, the gorillas, our ancestors, eat plants; therefore, humans should. No, the internal anatomy of a gorilla is very different from a human, so check out the comparative absorption and the different internal anatomy in this “Homo Carnivorous” video.
The human body is made to absorb animal products
The way I start is, what do people need in terms of nutrition? What we eat is different than what we absorb, or what an animal eats is different than what it absorbs. In the video, Barry will show you that actually, the bacteria inside an herbivore turn the grass and the grain into short-chain fatty acids, and the protein that a ruminant animal gets is actually the bacteria itself. A couple of my patients have addressed their medical concerns by cutting out vegetables and by doing carnivore-type diets. So in the short run, I think there are clear examples of how a carnivore diet can be healing, actually.
Studies on the carnivore diet
There was a survey done by the Harvard Nutrition Group, Dr. David Ludwig and Belinda Lennerz, who surveyed a social media group of folks doing a carnivore-type diet. It’s a publication in Current Developments in Nutrition, and they had about 2,000 respondents who said they were doing carnivore diets, and put in their health information and blood tests. There are at least some social media publications about what people say they’re doing. However, that’s not sufficient to sign off on it. It’s not enrolling people into randomized trials, and the selection bias of people who do well generally join these groups. It is like the people who go to high school reunions are generally doing well. This doesn’t tell the whole story. It’s really important for prospective research to be done on any type of diet, including the carnivore diet, and I haven’t seen that done. I know there was some grassroots attempt to get these research studies going. I’m not sure of an update on that, but I’m curious and cautious about those.
Does the carnivore diet offer all of the nutrients humans need?
Amber O’Hearn said in her paper that there might be a few nutrients of concern, for example, calcium if you don’t eat the bones. There are a lot of animals that are carnivores which do eat bones. You might also get calcium from fish. Like any extreme diet, you want to follow a reasonable teacher who has done it for a while and can tell you the possible pitfalls. If you are going to do a vegetarian or vegan diet, you want to make sure you know about the need for Vitamin B12, for example. Vitamin B12 is really an animal source nutrient. There’s really not anything in the plant kingdom that isn’t available in the animal-sourced nutrition. Yes, the amounts of certain things are different, like vitamin C is the one everyone talks about, but the cultures that were carnivorous, like the Inuit, didn’t have scurvy as a problem, which is the vitamin C deficiency. So either there’s enough vitamin C in the way they were eating the food, or it’s not needed as much if you don’t have a glucose-based metabolism. That’s one current level of thinking.
The carnivore diet is a mixed bag. There are possible benefits from it, especially if you are sensitive to the things that are in vegetable matter. However, we’re a little bit worried about getting all of the nutrients you need for a long period of time just because it’s often a period of years before a nutrient deficiency, a minor one, will become apparent. But I’m open. I think new science needs to be done. In the meantime, if you’re going to do this, you do it under the direction of someone who’s been teaching lots of people, and you want, like anything, you want to measure everything that doctors typically measure to know that you’re in good health. Although, I’m finding that there may be a new normal of the blood levels, so that you don’t want to be forced into treatments of blood levels because it just seems like it’s different. For example, if you’re on a keto or carnivore diet, you might have ketones in your blood; it’s not abnormal, that’s normal for someone who doesn’t eat carbohydrates. If you compare it to a lab value of all of those people who eat carbohydrates, it will look abnormal because ketosis isn’t typically seen in those who eat carbohydrates, and our laboratory values are from people who eat carbohydrates.
You want to go into this with your eyes wide open. I’m not against something that seems reasonable, and we just don’t have long-term data yet. I’m not fear-mongering about the idea that since we don’t know, it must be bad. A lot of people take that position, which I think is lacking curiosity and maybe a little bit smug. Eyes wide open on this one, it may actually turn out to be good. Watch the full video here.