Unexpected Results from the Carnivore Diet
Here's the story: A bunch of people with medical conditions like obesity, diabetes, autoimmune disorders, gastrointestinal problems, and any one of several other miserable things decided to cast their fate to the winds of the carnivore diet. No plants. No fruits. No Cocoa Krispies. Just meat. Scores of chickens. Petting zoos of lambs, small herds of steer, and sties full of pigs.
The conventional thinking is that such a diet would ultimately lead to poor health, but that's not what a study of over 2,000 human carnivores found.
American researchers from various medical centers, universities, and research centers collected self-reported data from respondents who'd been following the carnivore diet for at least six months. Their goals were as follows:
- Characterize the diet consumed by participants.
- Describe perceived health status and any changes in health since starting the diet.
- Assess perceived nutritional deficiencies or other adverse effects.
- Evaluate the satisfaction and practicality of the carnivore diet.
The respondents were recruited from a slew of social media platforms, including Facebook, Instagram, Twitter, World Carnivore Tribe, and others. While the researchers received info from 3883 dieters, only 2029 were eligible and willing to jump through the requisite hoops (filling out survey data forms).
Beef, lamb, venison, buffalo, goat, and other non-pork red meats were the most commonly consumed foods, followed by eggs and non-milk dairy, pork, poultry, and seafood.
Organ meat and non-milk dairy was consumed at least once a week by 42 and 72% of respondents, respectively. Fewer than 10% of them ate starchy vegetables, non-starchy vegetables, fruits, or grains more than once a month.
Most of them seemed to think that their meat-heavy diet would meet their nutritional requirements, as only 37% reported using any vitamin supplements.
Amazingly, most of the participants reported improved health outcomes. Nearly every chronic medical condition either resolved itself or showed improvement. The only exception (among things reported) was ophthalmologic conditions, where only 48% (just shy of a majority) reported resolution or improvement of their eye problems.
For the vast majority, general health improved, as did energy, sleep, strength, endurance, mental clarity, memory, and focus. Everything got better. Eating meat appeared to be a cure-all.
Here are a few examples of the tallied responses to certain chronic conditions:
Fewer than 1% experienced worsened conditions. The only rotten piece of meat in the statistical butcher shop concerned LDL cholesterol – it went up significantly in most respondents.
However, triglyceride levels remained favorable, and the scientists offered up the theory that LDL cholesterol elevation, when coupled with normal triglyceride levels, may reflect "more buoyant" lipoprotein particles, which might mitigate any increased cardiovascular risk.
Also reassuring was the fact that as LDL cholesterol rose, so did levels of desirable HDL cholesterol. Plus, the associated weight loss and improved insulin sensitivity might also reflect positive cardiovascular outcomes.
Further, the respondents LIKED being meat-eaters. It provided high levels of satisfaction and it had little social impact. Even their doctors didn't tsk-tsk them, especially when they saw the proof-in-the-meat pudding.
We have to be careful when analyzing studies like this. Remember, all the info presented was self-reported. There was no objective, second-party analysis of any of the data. No physiological exams. No way of telling if they weren't lying their meat-stained pants off.
And there's the possibility of "selection bias." Respondents who might not have had success with depending so heavily on their canine, meat-tearing teeth might have abandoned the diet and therefore not reported their results.
Still, the published results are intriguing, thrilling, and frustrating, all at the same time.
There's not much historical precedent for meat-only diets in humans, at least not in our recorded, non-caveman history. As the authors of the paper point out, most of what we know about such diets can be gleaned from two sources: Arctic societies or the treatment of diabetics in the 19th century.
Regarding the former, they've famously existed on animal-based diets with very little plant matter for a very long time. Most have displayed no vitamin deficiencies of any kind, but Arctic societies depend heavily on organ meats, which are incredibly rich in vitamins, even more so than many fruits and vegetables.
As far as diabetics, in 1797, a Dr. John Rollo successfully treated two diabetics by putting them on a meat and fat diet where they avoided plant foods entirely. This pretty much became the standard treatment for diabetics until insulin was invented. Even so, these meat-eating diabetics didn't live that long.
Another recent meat-eating study compiled results from 175 countries and declared, rather disingenuously, that eating meat makes you live longer. Instead, what you gather, after you read the entire study carefully, is that it wasn't specifically meat that contributed to good health and a long lifespan, but all-around proper nutrition.
But that brings us back to the carnivore diet survey. My initial response, as it might be for you, was to start eating breakfast, lunch, and dinner at the Outback Steakhouse. But is that smart?
Let's look at the results objectively (which, for me, as a devoted "well-rounded diet" guy, is a little difficult). As the study authors point out, over 50% of the respondents started the carnivore diet to improve allergies, skin conditions, autoimmune conditions, digestive problems, or inflammatory conditions in general.
Given that most food allergies and inflammatory responses arise from plant-based components, it appears to make sense that a carnivore diet could work. However, anyone who avoids plants is missing out on the vast array of polyphenols and carotenoids, many of which have also been shown to have anti-inflammatory effects, as well as a breathtaking array of other health benefits.
And then there's the question of certain critical nutrients. Humans require vitamin C, and they get most of it from plants. You can certainly get enough vitamin C from organ meats, provided you eat the organs raw, or at least rare.
However, only 42% of the respondents ate organ meat at least once a month. That may not be enough to compensate for any vitamin C deficiencies, and it certainly doesn't bode well for those that didn't ingest organ meats at all.
Calcium, too, might be a problem. Meat contains very little, but they'd likely get all they needed from dairy sources, provided dairy was part of their diet.
Are the trade-offs worth it? It certainly seemed to be in the case of the respondents, but would they suffer in the long run? Remember, many of them had only been on the diet for six months. It'd be nice to revisit them again in a year or so.
As far as why the carnivore diet seems to be a cure for what ails you, there might be a relatively simple or at least straightforward explanation, one the authors didn't bring up.
The most immediate result from eating a meat and fat diet concerns insulin, or rather, lack of it. While the amino acids in meat do, in fact, elicit a rise in blood sugar and a corresponding rise in insulin, it's marginal, especially when you combine the protein with fat.
However, plant-based foods, particularly starchy plant-based food, elicit high blood sugar levels and large insulin responses. If chronically high blood sugar levels aren't ameliorated by exercise, anti-hyperglycemic drugs, or certain polyphenols or carotenoids, they can lead to a number of physical maladies, chief among them, of course, diabetes.
If, however, you build/re-build insulin sensitivity by eating foods that don't elevate blood sugar, like meat, you generally lose body fat. That in itself has a plethora of downstream benefits. Being lean suppresses inflammatory proteins that can cause a host of problems, including cardiovascular problems, autoimmune problems, and even dermatological problems.
These same inflammatory proteins can even damage the nerves around the gut, which can lead to symptoms of IBS and gastrointestinal problems in general.
All of this happens because of high blood sugar and insulin insensitivity. And therein lies the possible answer to all or most of the benefits of the carnivore diet – favorable blood sugar levels and increased insulin sensitivity.
Again, I'd like to see what happens to the carnivores after a couple of years. I suspect the nutritional deficiencies and lack of beneficial phytochemicals would catch up to them. Of course, Arctic peoples have been eating meat-based diets for a long time and done relatively well.
That being said, Arctic populations generally don't face the same stressors as people in industrialized societies might, like pollution, xenoestrogens, processed foods – all things that carotenoids and polyphenols might combat. (Not to say that having to fight for survival in harsh Arctic climes isn't a stressor.)
Obviously, there are plenty of ways to keep blood sugar low and remain insulin sensitive without becoming an obligate carnivore. One simple way is to stick to a Mediterranean-ish, high omega-3, lots of olive oil, lots of supplements, lots of fruits and vegetables, and lots of fish and moderate-meat diet.
That's the path I'll continue on, at least until more definitive info is available.
- Lennerz BS et al. Characteristics and Self-Reported Health Status among 2029 Adults Consuming a "Carnivore Diet." Curr Dev Nutr. 2021 Nov 2;5(12):nzab133. PubMed.