The Carnivore Diet: Good or Bad Idea?

Enter the latest fad diet: The Carnivore Diet. You might think from the title that it’s pretty much the same thing as paleo or keto, but this one takes carb avoidance to a whole new level. On the Carnivore Diet, you’re only allowed to eat meat, fish, and animal products including eggs and limited amounts of dairy (the parts that don’t contain lactose). That’s it. No veggies, no fruit, no legumes, nuts, seeds, grains… nothing else. 

Proponents claim that this diet can help with weight loss, arthritis, diabetes, anxiety, depression, migraines, and more.

Weight Loss, Diabetes, Metabolic Syndrome, and the Carnivore Diet

Would you lose weight on the Carnivore Diet? Probably, for the same reason that you would lose weight on the keto diet: you’ll be eating a lot of fat and protein, and (ideally in this case) zero carbs. Carbs are the body’s preferred source of energy, though it can, with effort, convert protein into glucose if need be. The body cannot convert fat into glucose though; fat can only turn into ketones, an alternative energy source. As a result of low glucose levels, insulin will plummet, helping to turn around diabetes and Metabolic Syndrome. And, of course, you’ll also lose weight (unless your body thinks it’s starving and puts on the breaks, which can happen with any low carb diet).

Does the Carnivore Diet Help Arthritis, or Decrease Inflammation?

Like any of the other diets mentioned (paleo and keto), the Carnivore diet will cut out many of the common allergens, as well as highly processed foods which are inherently inflammatory to everybody. For this reason, I don’t doubt the testimonials that claim the Carnivore Diet decreases inflammation.

As for migraines, according to this study, there is also a mast cell connection. Mast cells are those cells that hold and release histamine; but they also store serotonin. When allergies—be they food, environmental, or chemical—trigger the release of histamine, they can also release serotonin, triggering the blood vessels in the brain to constrict. The body always seeks balance, though, so this leads to rebound vasodilation, and therefore, a migraine.

The point: if your diet, whatever it is, cuts out foods that are allergenic to you and therefore can trigger this process, then it may well decrease migraines.

Does the Carnivore Diet help Anxiety and Depression?

Long-term stress depletes both dopamine and serotonin, the neurotransmitters associated with positive feelings. Stress eating occurs because sugar is a quick way to raise both of these in the short-term: in addition to helping glucose get into cells, insulin also allows amino acids from the protein in our diet (such as the precursors to serotonin and dopamine: tyrosine, phenylalanine, and tryptophan) to cross the Blood Brain Barrier (BBB). A craving for sugar may therefore really be a desire for more dopamine and/or serotonin.

But of course, if you’re eating straight carbs, while you’ll feel better briefly, you’ll end up depleting your already low stores of dopamine and serotonin because you haven’t replaced them with anything. Again, their actual source is from amino acids, found in protein: tryptophan, phenylalanine, and tyrosine. So eating more protein and keeping the blood sugar off the roller coaster certainly will help mood long-term. But this is also true of the paleo and keto diets, as well as any whole food-based diet plan.

The Down Sides: Lack of Fiber

Here are my concerns with a diet this extreme.

Fiber is found in plants, not animal products. A diet of all animal products will therefore lack the fiber necessary to keep your microbiome healthy. This can increase the risk of colon cancer, and (since about 80% of your immune system is in your gut) can also decrease immune function generally. An unhealthy gut can be a gateway to all sorts of evils. 

The Down Sides: Nutrient Deficiencies

Meat does not provide adequate amounts of Vitamin C (found highest in citrus fruits, broccoli, and bell peppers), Vitamin E (found highest in nuts, seeds, oils, wheat germ, and avocados), or folate (which is found in salmon, eggs, and dairy, but is highest in green leafies, berries, citrus fruits, and legumes.)

Low Vitamin C causes scurvy of course, if it’s extreme. Symptoms include bleeding gums, anemia, fatigue, aching bones, joints, and muscles, and poor wound healing. This could be exacerbated by low Vitamin K2; while Vitamin K1 is found in meat, the gut flora converts it to K2, and this likely wouldn’t happen as efficiently given the low fiber and likely microbiome disruption. Low K2 leads to easy bruising, bleeding gums, and poor wound clotting, as well.

Low Vitamin E causes loss of reflexes and gait disturbances.

Low folate can lead to depression (working at cross purposes there) and other behavioral disorders, loss of appetite, weakness, headaches, megaloblastic anemia, and glossitis (inflammation of the tongue).

While an adherent to the Carnivore Diet could offset both the low fiber and the low nutrient problem with supplements, taking supplements isn’t just as good as eating the food they come from. While I do believe that supplementation is unfortunately necessary in our world to offset nutrient depletion in the soil, there is increasing evidence that the bioactive compounds in foods work together synergistically.

So it’s not a good idea to just skip the food altogether and go straight for the supplements. It’s just not the same. 

The Down Sides: Sources of Meat

I wrote here about the health (not to mention animal rights) concerns about agriculture-industry meat products. The upshot is, they’re full of chemicals, hormones, GMO feed, and saturated fat (which isn’t bad in and of itself, but it can become bad if there are no essential fatty acids to counterbalance it.) Organic and free range meat (and wild-caught fish) can overcome these difficulties, but it’s very expensive. I can’t imagine how pricey it would be to consume a diet comprised entirely of organic and free range meat, and wild-caught seafood! For this reason, I have to assume that most people who are on the Carnivore Diet are going with the more reasonably-priced alternative: agriculture industry meat. Which is fairly toxic.

It’s even worse when cooked at temperatures above 300 degrees F, as these temps induce chemical changes that render the meat carcinogenic (and this would be true of the organic meats too). We all need to be aware of this when choosing how we prepare our animal products, but this issue would be compounded in someone whose diet is comprised of nothing but. 

Along those lines, processed meat products like bacon, sausage, hot dogs, etc, have been shown to be carcinogenic, unless nitrate-free. Nitrate-free processed meat products are available, but are also pricier than their nitrate-containing alternatives.

The Down Side: Acidity

Meat and animal products are very acidic, and while your blood has an awesome buffer system that can offset this problem, there’s no such thing as a free lunch: the buffering components have to come from somewhere. Where they come from is the bones, and then they get processed in the kidneys—which, over time, might increase the risk for osteopenia, osteoporosis, and/or kidney stones. I wrote more about this process here.

The Upshot

My suspicion is that proponents of the Carnivore Diet are primarily reaping the benefits of what the diet does not contain: namely, common allergens, processed, and inflammatory foods. Elimination of these foods will likely produce a host of health benefits.

That said, to me there are significant drawbacks that could be avoided, while the benefits could remain, with a less restrictive diet.