I have been planning to do a scientific review of various diets later this year, but with everyone talking about the Carnivore Diet, I felt compelled to speak about it rather sooner than later. Mind you, since it's a new trend, there is not much scientific data on this nutritional approach to begin with and I didn't have enough time to do a comprehensive scientific review, so today I will just share my impressions and some thoughts on it. I will definitely do a more thorough review later.
I would like to start with acknowledging some personal bias and expressing some skepticism related to all the hype about this "new" diet. I have been a huge proponent of low-carbohydrate living since 2002 or so and I have heard a lot of arguments against it. In part, the reason for creating my own YouTube channel was to stop convincing skeptics who do not hear your scientific arguments. Based on what I know, I see the Carnivore Diet as an extreme form of a low-carb diet – you just take one step further in eliminating carbs and here we go – you are eating exclusively animal products.
At this point, my bias is in the fact that I've been a proponent of essentially the same approach and I am supposed to support it wholeheartedly. But I prefer to be cautious and reserved in drawing my conclusions and making any recommendations now, so I'd like to express some criticisms and to propose some alternative explanations to the effects of the Carnivore Diet claimed recently by some quite influential bloggers and media personas.
First and foremost, I do not think that the carnivore diet substantially differs from a typical low-carb diet. In order to benefit from a low-carb diet you are supposed to limit your carbohydrate consumption, ideally down to 20 g of digestible carbs per day or even less. Plus, you'd have some fiber that we cannot process, but it helps with bowel functioning. So, if you transition to a completely animal-based diet you're effectively changing less than 5% of your macronutrients (20 g of carbs = 80 kCal = 4% of an average 2000 cKal diet). I doubt that such a change would be substantial for an average individual. And here we can talk about a couple of claims made by the carnivore diet proponents.
1) Plants are "chemists" and they try to protect themselves by poisoning us with toxins: This one is a bit ridiculous, but we can definitely think it through – as a truly open-minded person I never reject ideas without giving them a chance. So, I'd like to say that indeed many plants produce toxins that we use. The best example would be tobacco – nicotine in it is a perfect insecticide and we use it as such (as well as the tobacco plant). There are quite a few medicinal plants that we use for treatment of heart disease, hypertension etc. Some plants are hallucinogens, some have stimulant properties like coca leafs etc. There are lots of them, but are all of the plants toxic? The answer is no. Ok, I'll counter that presupposition with a question – how do herbivores survive? I bet the answer would be "they adapted / evolved". Well, what makes you think that we haven't? As much as I can't agree with some people saying that we are herbivores, I cannot agree with the fact that we are obligate carnivores – we definitely can process quite a few plant-based foods. Also, not only we have evolved, but we have highly selected and modified lots of plants to make them more suitable for consumption. On top of that, I can give you quite a few examples where plants would be "interested" in animals consuming them – most of the berries are meant to be consumed by animals, pass through their digestive systems with the seeds intact and "planted" into the soil with feces.
2) The Carnivore Diet "cures" autoimmune and inflammatory problems: I must say that I see how it can be helpful for some people with pre-existing issues – the diet is pretty much an epitome of the elimination diet. You just remove everything that might cause certain health problems in certain people (not everyone). They feel better and report success. I am not even skeptical about it, but what I'd like to see is a systematic study, not a bunch of anecdotes. Say, a group of people with autoimmune conditions should be monitored for several months on their regular diet and then switched to the Carnivore Diet for several months. All these peoples' symptoms, reactions and nutrient intake should be properly logged so that we would have data collected in a controlled fashion on everyone, not only on those who had some success with this diet and started feeling better.
3) Speaking of "feeling better" – I've seen quite a few people saying that they started the carnivore diet and immediately "felt better". I'm sorry, but it can be simply a placebo effect. Again, I'm not saying that the diet doesn't work, but I've heard people saying that they started "feeling better" on any diet. Ironically, it's especially prominent in vegetarians whose approach is the opposite to the Carnivore Diet. I've seen peoples' gastrointestinal tract functioning change when they received placebo, I've seen people getting "drunk" on placebo (and published it as case reports). Again, a proper research is necessary to clarify the effects.
The last item on my today's list is weight loss – people claim that they lost a lot of weight on carnivore diet. Again, I'm not surprised at all – they are effectively on a low-carb diet, which was shown to be effective for weight loss and likely are in caloric deficit. Their caloric intake likely doesn't differ much from what you'd expect on a typical low-carbohydrate diet and, as I said many times before if these people are consuming too many calories, they won't lose weight, but if their diet is hypocaloric, carnivore or not, they will lose weight. The carnivorous nature of the diet doesn't make any difference here. Again, a simple randomized controlled trial would be a perfect proof of this statement. To be honest, I would be happy to be wrong in this case as long as research gives us a definitive answer.
In summary, I don't think that this diet is a major breakthrough – it's too similar to existing protocols – but it might be helpful for some people with certain conditions as a form of an elimination diet. It also helps with weight loss as long as it creates caloric deficit. I'm not saying anything bad about it, but at the same time I find it hard to endorse it as a panacea. Proper research is needed to make these claims and unfortunately at them moment these claims are made without being substantiated.
I wouldn't mind trying it myself (it's so close to my regular low-carb diet that it doesn't make any difference for me), and also for the sake of science I would appreciate your opinions and stories – if you are going to try it shoot me an e-mail or a post on my YouTube channel with the description of your before and after situation. Also, if you tried it and didn't work for you – let me know too, we have to see the other side of the coin too.
As always, I hope that you find this information useful and encourage you to subscribe to both this website and to my YouTube channel so you won't miss anything. Feel free to ask questions, make comments – I'm always happy to answer them.
Sincerely Yours,
Dr.Sam