Yes, the Carnivore Diet comes with side effects and yes, they are not awesome. But they are mostly short-lived and relatively easy to get through. The most common side effects are diarrhea, constipation, nausea, headaches and cravings. These are just part of the withdrawal and adaptation phase.
What are the Carnivore Diet Side Effects?
If you’re starting the Carnivore Diet, like any diet, there will be side effects. Many of them will be benefits, but some of them – not so much.
Let’s discuss the most common side effects you may experience in your first couple of weeks on the Carnivore Diet. They might be less than awesome, but forewarned is forearmed.Â
Let’s get into detail about what these side effects are, and how to get through or fix them.
Carnivore Diet Side Effect 1: Diarrhea
Why Does the Carnivore Diet Cause Diarrhea?
The first side effect is arguably the most common. So common in fact, that there is a saying in the Carnivore community “Don’t trust a fart”.  Rest assured this does pass.
Why does this happen? There are 2 main reasons why diarrhea is so common.
First is a change in the microbiome. By removing all carbohydrates, fiber and processed foods, bad bacteria in the gut start to die off. The gut will be flushed with water to clear out the dying bad bacteria, causing the diarrhea.
Second could be related to increased fat intake. This does not mean fat is bad, just that the body is unaccustomed to digesting high levels of fat. The body will adapt over time.
How to manage the Carnivore Diet side effect of diarrhea
To manage the first issue of the change in microbiome, unfortunately the only thing to do is wait. This should be over within a week. Do your best and be prepared.
If the diarrhea has not subsided or eased significantly within a couple of weeks, it is now likely due to fat intake and not being able to digest properly.Â
Here are some tricks to manage fat intake if this is causing diarrhea:
- Reduce the amount of fat you are eating. If your body is not able to handle the constant intake of fat, ease up on that. Eat leaner meats for a couple of days, or eat a meal of lean meat followed by a meal of fatty meat to space out the fat intake. Â
- Do not eat hot rendered liquid fat. This will go straight through you. Even Carnivores who have been on this diet for years generally are careful about consuming hot liquid fat. This tells you that even after full adaptation, hot liquid fat causes toilet issues. Most commonly, this is the fat left in the pan after cooking ground beef. Drain that.
- Do eat warm semi-solid fat. This is the glorious melty fat on the side of a steak, or some fatty offcuts crisped up in the air fryer. This is an excellent source of fat and though it is hot, is much less likely to go through you quickly.
- Do eat cold fat. This is butter straight out of the fridge. This is also an excellent source of fat (if you can tolerate a small amount of dairy). Most people find eating butter this way (myself included) is an excellent way to increase fat intake without causing any digestive distress.Â
Fat is the ideal source of energy on the Carnivore Diet so work to increase your fat intake slowly, with the fats that will be gentle on your digestive system.
Carnivore Diet Side Effect 2: Constipation
The second side effect on our list is the flipside to diarrhea. As we’ve discussed, the microbiome is going through a shift when you change your diet.
If you have struggled with diarrhea, you might find yourself struggling with constipation for a while afterwards. The bowels have cleared and they are no longer being filled with copious amounts of fiber.  Conventional wisdom tells us that without fiber, we can’t poop.
This is patently false, as there are many people who have followed a carnivorous way of eating for over 10 years. If they were unable to relieve themselves, they would likely be dead. But they’re not (they’re happy, healthy and thriving) so that just proves the narrative incorrect.
Consider also the case of an infant. For the first 6 months of their lives, babies do not take in any fiber. I can certainly assure you, they have no trouble relieving themselves either.  How can fiber be a dietary requirement if it is not present in arguably the most important developmental stage of a human?
How Often Do You Poop on the Carnivore Diet?
Which leads us to constipation (or the illusion of it). Keep in mind, just because you are not doing twosies every day does not mean you are constipated. Once the body adapts to eating a Carnivore Diet, most people find they go once every 2 or 3 days.
Meat is incredibly nutrient dense and has high bio-availability. This means much of it is absorbed during the digestive process and not much waste remains, unlike a high-fiber diet. This naturally results in less waste, thus going less often.
If you’re not in pain, and don’t feel the urge to go, then you’re probably not constipated.
Best ways to overcome constipation on the Carnivore diet:
- Hydrate – water and electrolytes can help, as can bone broth
- Increase fat intake – remember point 1 above where too much fat might cause diarrhea? Not enough fat could be worsening constipation.  Eat more fat (not the rendered, hot liquid unless you’re truly desperate) and experiment with how much fat it takes to get things moving.
Carnivore Diet Side Effect 3: Nausea
Like the first 2 side effects, nausea is largely owing to the changes that are happening in the microbiome. It could also be caused by eating too much fat before your body is ready for it. Again, this will get better with time.
If you think it’s too much fat that is causing nausea, try eating leaner cuts. Otherwise, some simple nausea remedies can include sparkling water or taking some electrolytes.
My preference is sparkling mineral water. There’s something about the bubbles that helps settle the stomach. I’ve never taken electrolytes personally, I just find them expensive and have never felt the need. If you do feel like electrolytes can help, LMNT is a popular brand among the keto and carnivore community
Carnivore Diet Side Effect 4: Cravings
Cravings are definitely a big side effect on the Carnivore Diet. What the cravings will be for is anyone’s guess, but they undeniably will turn up.Â
Cravings are really your brain’s attempt to access those sweet easy dopamine hits that arise from ultra-processed foods. As your hormones regulate over time though, the cravings will subside. Be prepared that this can take weeks or even months.
The best solution for cravings is to eat more meat. Yes, I know. A diet that tells you to eat more. But meat (fat and protein) is more satisfying than any other food on the planet.Â
Being full and satisfied is the number one best way to defeat cravings. When you are full and satisfied, cravings are less likely to rear their ugly head. If they do show up, it is much easier to get through the craving and say no.
Trust me when I say this. If I (a self-diagnosed sugar addict) can stand in the chocolate bar aisle at the grocery store for 10 minutes trying to decide which one I want most and walk away calmly, having made the decision that I don’t really want any of them – that is the power of satiation. That is the power of eating meat.
Carnivore Diet Side Effect 5: Withdrawals
Withdrawals on the Carnivore Diet are no joke. In fact, all of the side effects previously mentioned (diarrhea, constipation, nausea and cravings) are really all withdrawal symptoms. It just goes to show how much of an effect some foods can have on the brain and body.
There are other withdrawal symptoms that you may experience as well in the first couple of weeks:
- Headaches – this is a classic detox symptom, and is nearly unavoidable if you decide to quit coffee at the same time (as I have). Fortunately, the headaches only last a day or two and can be managed quite easily with some aspirin if you are so inclined.Â
- Fatigue and lethargy – the Carnivore Diet removes the glucose (carbohydrates) that your body has been reliant on for energy. This means your body will need to relearn how to burn fat for energy. This will happen in due course, but in the meantime you might find you are struggling for energy.
- Irritability – this comes hand in hand with the fatigue and lethargy. Removing the easy energy source and the dopamine hits from processed foods leads to an unhappy brain in the short-term.
Withdrawal symptoms are inevitable and the only way through them is time and patience.Â
Conclusion
The Carnivore Diet definitely comes with some side effects. These are mostly short-term and mild and are related to withdrawals. Whether you are coming from a standard American diet (SAD) or a ketogenic diet, you might still experience some of these symptoms. Being prepared for them will ensure you successfully see them through to the other side.
Though the Carnivore Diet has some side effects that are to be expected, they are generally mild. If you have any concerns about any side effects or symptoms you may be experiencing, please see a doctor.
Additional Resources
Find all Carnivore Diet Beginner and Basic articles here
Excellent resources and further reading on the Carnivore Diet
