Side Effects Of The Carnivore Diet

17 min read
What You're About To Get Into
Why carnivore can be accused of being too restrictive.
The real side effects you can expect on carnivore.
How to prevent those side effects from wrecking your day.

Surely This Diet Can’t Be All Sunshine And Rainbows

There are a host of reasons to take a chance at this all-animal affair. It’s zero carbs, effectively forcing the body to turn its own fat stores into a fuel source. It can drastically cut down the surges of systemic inflammation, making it a very viable way to douse the flames of autoimmune and anxiety disorders. The limited array of foods counters the buildup of decision fatigue, which would otherwise put the office space dieter at the mercy of passing doughnut trays. 

There’s always a catch with these milk-and-honey promises. A diet this restrictive is bound to cause a few casualties along the way. If not in the first few weeks, then at least when it’s pushed into the long term. That’s when the wheel tends to snag on a rogue nutritional imbalance, your hormones get disrupted, and your face slams into the proverbial dirt. 

This is a question of whether the carnivore template is optimal for health, whether you can head into your 30 day makeover with peace of mind. And it’s worth pointing out that at this point, there are no long term studies to establish the possibility that you won’t keel over on the second anniversary. 

But there aren’t really any diets that come with the warranty of clinical long-term data. So things are always going to look a little murky, regardless of the diet you choose to play with. Nothing comes guaranteed. What we can do, is peer at the data and experience we’ve assembled at this point. And with that, make an educated guess on whether carnivore could be the diet that goes the distance. In that vein, I’ll tackle the classic charges that get brought up against this way of eating.

Dairy Intolerance

Carnivore itself has a few variations. Since all animal products technically get the greenlight, some make the most of it by throwing in a mountain of dairy. Since we have billions on the planet with a genetic inability to digest lactose and casein, that’s a problem. In this case, the imminent bowel crisis could be sidestepped by sticking to the fermented products, such as butter, cheese and yogurt. The lactose gets chomped up by bacteria during the fermentation process, leaving only trace amounts that are unlikely to cause issues.

That being said, the sensitive folk can still end up getting side effects, especially with the high histamine content in fermented foods, which is its own beast.

Dairy Side Effects
Skin breakouts
The Fix
Avoid milk for its high lactose content, while moderating the rest. But if push comes to shove, you may need to ditch this group altogether.

Nutritional Deficiencies

Here’s the one that’s most likely to come up from a concerned facebook relative. Surely you need to be eating your way through the rainbow in order to allow the body to remain healthy? Carnivore has the notoriety of containing about zero of the coveted five-a-day foods. That’s an inescapable sin the books of most dieticians. A multicoloured cocktail of fruits and vegetables contribute to a bulk of your vitamin and mineral requirements. A nutritional strategy that avoids the overlying issue: plants just don’t digest that well. They’re packed with antinutrients, severely limiting your ability to absorb any plant nutrients into your biochemistry.

On the meat side, you have walking all-in-one nutritional powerhouses. Beef liver, by the numbers of density and diversity, is the most nutritional food on the planet. A few servings of liver can easily make up for any shortcomings in muscle meat.

The body’s requirement for carbs nicely matches the typical macros involved in carnivore: zero. The brain is often said to rely on glucose, but those cells can gobble up fat-derived ketones just as greedily, at least once a bedding-in period has been allowed. Any remaining needs for glucose are met by gluconeogenesis, the process of turning amino acids (protein) to sugar. All the bases are covered. 

See My Article – How To Meet All Your Nutrient Needs In Carnivore

Side Effects Of Missing Carnivore Nutrition
There shouldn’t be any deficiencies in a well-rounded carnivore diet. Red muscle meat, liver, oily fish, hard cheese, and you’ve got yourself the whole set.

The Myth Of Keeping A Healthy Gut

To sum up what we know about making a healthy functioning microbiome: we just don’t know. The study of those little creatures living on our digestive tract, is still in its infancy. We do know that they play a huge role in our biochemistry, we just don’t quite know how they go about it. We also don’t have the means of lowering a population of ‘bad’ bacteria, while increasing the ‘good’. So the standard advice of ramping up fiber to feed the gut can end up turning a gut imbalance into full blown dysbiosis.

Not that you should necessarily resort to starving them out. Carnivore may lack the fiber to produce short-chain fatty acids that can go towards fuelling the gut. But it does have plenty of ketones, which can charge the microbiome by lending butyrate from betahydroxy-butyrate (BHB). Butter is also a great source of butyrate. The gut isn’t going to wither away and die without its favourite box of whole-grain cheerios.

As for the lack of diversity in foods that could result in a few populations of bacteria dying out, it would be hard to call that a bad thing. If those species are relying on sugars to survive, then they’re part of the problem that’s leading you to the fridge every evening.

The carnivore diet is an elimination protocol that would be more than capable of pulling you out of such a mess. By removing  the foods that cause indigestion and feed bacterial overgrowth, it can do wonders for ameliorating the symptoms of gut dysbiosis. And if anything, the perks only stand to get better with time. It’s not a side effect as much as a stand-out benefit.

Side Effects Of No Fiber
As the ultimate elimination diet, carnivore is brilliant at solving digestive disorders. And it can manage that just fine without turning the gut into a wasteland.

There are more bones to pick through. The apparent lack of fuel But rather than spending too much time quelling controversies, let’s look at the side effects that will likely arise on a carnivore diet. And I’ll start with the most obvious one in the room. 

The Keto Flu Initiation

Keto flu, an affliction that strikes carnivore as it might the standard Atkins version. This is a consequence of stealing away the carbs from the modern sugar-crazy metabolism, and leaving it in an energy purgatory. There’s no glucose coming in, and gluconeogenesis is far too slow of a process to shoulder the brunt of the body’s needs. Which leaves the ball squarely in the court of fat metabolism, but the body may well require some time to adapt to make the most of its own stores. 

This means there’s often a transitional phase, where fresh carnivore initiates have to grind through a few weeks of low energy, nagging hunger, and the occasional mild migraine. It’s the testing grounds for those seeking out the promised land.

But there’s no reason to suck it up, because you can sidestep most of these sides by making sure you’ve got plenty of electrolytes and fats coming in. That allows you to steady the ship while you wait for the body to reorientate itself. A bulletproof coffee in the morning, with a healthy pinch of salt, isn’t the worst idea for starting the day.

Side Effects Of Keto Flu
Brain fog
The usual soul-sapping cocktail that shouldn’t linger too long past its welcome.
The Fix
Ramp up your intake of electrolytes and high-fat foods while you wait for it to blow over.

Unrelenting Cortisol

Cortisol is a stress hormone that typically gets portrayed as the harbinger of doom, and the breaker of a peaceful content lifestyle. But like with any mechanism in the body, it’s not inherently a bad thing. The morning spike of cortisol is pivotal for lending you the energy to roll out of bed, and it’s equally decisive for healthy immune function. The problem arises when it’s constantly prodded into action, to the point where the body becomes resistant to its effects. More cortisol is secreted to get over the bump, and that gives way to chronic low-grade inflammation and cortisol levels that refuse to climb down before bedtime.

Acute pulses of cortisol are absolutely healthy. Chronically elevated levels, that’s where the damage is. Insomnia, anxiety, lethargy, muscle soreness, are just a few ways lingering stress can wreck the system.

Preventing this, or solving it for the matter, is really about balance. If everything you do spikes cortisol, then that’s contributing to excess stress. So you might want to be careful about throwing the switch too often. Fasting is a classic cortisol trigger, and low-carb diets like carnivore essentially mimic fasting by being devoid of insulin. Then there’s exercise, which naturally goes along with a fitness transformation. You’ll be unable to avoid spiking cortisol, and that’s absolutely fine.

The real trick is in managing sleep, nutrition, and recovery to ensure that you’re able to bring down cortisol in between episodes of fasting and training. All of these are excellent ways to pull the body down into a parasympathetic state, otherwise known as the rest and recovery system. Cortisol naturally plummets. And if that isn’t enough to balance the system in the face of all that nervous dieting, then there’s nothing wrong with throwing in a few carb-ups during the week. Carbohydrates elevate the neurotransmitter serotonin, which can put you in a happy stupor while bringing down cortisol. 

There’s nothing sinful in eating an apple every once in a while, just as long as it doesn’t break down the mental wall that was holding you back from a week-long chocolate binge. That comes down to your character. Some work better with complete abstinence, whereas others can allow a little bit of leeway. I’ll let you figure that one out.

In any case, carnivore does far more to curb cortisol than it has any part in fanning the flames. Since plant toxins and excess sugar play their role in ensuring the body is constantly sent reeling into an inflammatory state with each meal, taking them off the menu does wonders for curing chronic stress. So really, the ‘fasting spikes cortisol’ idea doesn’t have much weight to it.

Side Effects Of  Excess Cortisol
Poor recovery
The Fix
Make sure you’re doing the stuff that brings down cortisol levels. Include mindful practices like meditation and forest walks, ensure the body gets the full spectrum of nutrition, and hit the hay like it’s your life’s mission. In the meantime, taking on stress and learning to weather, even embrace the discomfort, will drastically reduce the negative effects of that stress.

It’s a tool of progress, not a demon to be avoided.

Read My Guide – Train For The Process, Not The Outcome

Histamine Reactions

Histamine is a multi-talented organic compound that acts as a neurotransmitter while also contributing to the immune response. Unfortunately, it’s the latter that tends to cause the speedbumps, as some unfortunate people will be a little too sensitive to high histamine content in foods. The reaction comes much like a seasonal allergy, with flushed skin and itchy sensations. This means that certain foods on carnivore are going to be tricky for those sensitive to histamine buildup. Fermented foods like cheese are notoriously high, while meat that’s been exposed to air, such as ground beef, can also be problematic. If you have histamine issues, then it may be best to skip the following foods and stick to fresher varieties.

  • Cheese
  • Ground beef
  • Bone broth
  • Gelatin
  • Liver

Fortunately, there is a way around this, but it’s not going to be for everyone. Kidney contains the enzyme DAO, which helps clear out histamine. However, the taste is something, and may take a pinch of culinary excellence to navigate past.

Side Effects Of  Histamine Buildup
Flushed skin
The Fix
Minimise histamine buildup by sticking to fresh meat and avoiding the processed options. Including kidney will help out with your tolerance, but that’s going to take some courage.

Loose Stools

Talking about poop may be a step too far for the prudish, but we can’t pretend it isn’t a key activity in the day. A solid Type 4 on the Bristol Stool Scale shows that the digestive tract is doing its job, and all is well with the rear-end of nutrition. But people stepping into carnivore can be in for a rude awakening in the first few weeks, where they end up with regularly Type 7s, otherwise known as diarrhea. 

This is once again partly due to a system that’s caught in the process of transition, with no fiber to clog up the process. Everything happens faster, and that can have unpleasant results at first. The best option would be to lie low on the rendered fats to begin with, which would be the fat that pools when heated. So ground beef is again a suspect, and fresh meat would be a means of averting a crisis. 

If the problems persist, then it may be a lack of stomach acid. I’d warn against trying to supplement your way to safety. Beta HCL and bile acids can certainly help out, but it may be best to step back and let the body adapt to the new system. Manipulating one ingredient in isolation can have the unwanted effect of throwing the mechanism out of balance. Supplying the body with the stomach acid it needs can prevent it from figuring out how to supply itself. 

The lack of stomach acid could very well be the result of a nutrient deficiency. In this case, keep the rendered fat low, ensure you’re getting all your micros in, and maybe consider dining on intestines every once in a while.

Side Effects Of  Loose Stools
Lack of self-belief
The need to stay within sprinting distance of the bathroom at all times.
The Fix
Ensure total nutrition with meat and organs, while minimising rendered fats such as ground beef and butter. 

Lowered Tolerance For Carbs

There are a few layers to this. For one, the carnivore diet can drastically cut down on adverse reactions to foods simply by taking them off the menu and allowing the body the respite it needs to heal itself. That’s very much a positive. The issue may arise when you bring a few of those foods back into the diet. 

The side effects of accompanying plant toxins often feel amplified, far worse than they ever did when you were blissfully following along with the modern diet. Long-term carnivores often report worse tolerance for plant foods when they try and reintegrate them, particularly those dealing with autoimmune disorders. Broccoli often comes back with a vengeance. 

In a sense, it’s a sign that the body is more vigilant and aware of toxins entering your body. There’s a clear signal being sent that you shouldn’t be eating broccoli. In the modern diet, plant toxins become the norm, and the body doesn’t ever really shift from its chronically inflamed state. So an extra boatload of toxins in your lunchtime salad doesn’t get to change that. 

But in any case, this can count as a negative to those who’d much like to keep their social appearances carefree, and don’t want to be defined by the rules of a diet. Just keep in mind this tolerance issue only really shows up with people who were suffering in the first place.

Side Effects Of Ditching Carbs
Heightened reactions when attempting to bring plant foods back on the menu.
Reluctance to go back to all that suppression.
The Fix
Slowly reintegrate foods after a spell on carnivore, and restrain the comeback to one or two foods at a time. Play the patient game.

Summing Up – Take The Plunge

All in all, there’s not really much to be concerned about. There’s nothing here that can be classed as dangerous. There can be some mild discomfort involved, but that’s to be expected when the metabolism has to stage a wild U-turn. Carnivore is drastically different from modern cuisine, and that’s going to be pretty apparent during the first weeks. But the sweeping upgrades it can make to prop up a fitness transformation, makes it worth the pain.

And when I conceded that carnivores lacked long-term studies, that was only true in the sense of lab data. As it happens, this all-meat affair has a pretty decent track record. 

See My Article – Were Our Early Ancestors Really Carnivores?

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5 months ago

This is the best article on the carnivore diet I have read. Thank you! I strictly followed the vegan diet for five years. In the beginning there was nothing wrong. After 3 years I started having bowel and digestive problems. After some research I arrived at the elimination protocol. Too bad I didn’t discover this article then. I feel like I’m browsing through my own story through this article. Also including the solutions. I have gone through all the negative aspects and almost all of them have been resolved. Histamine was a big problem for me.

By water fasting for five days and then following the carnivore diet for a month (with the tips you describe in your article), I can slowly tolerate fermented foods again. 🙂

My source of information was by watching various YouTube podcasts. Do your own research and don’t accept everything at face value. You really have to get to know your own body.

What works for you may work the opposite for someone else. 🙂