It may be the case that almost all of the challenges people experience on a carnivore diet come back to dysfunction in the digestive system. Digestive dysfunction is extremely common as a result of a Standard American Diet, and if this exists prior to adopting a carnivore diet, the carnivore diet can, unfortunately, bring these issues to the forefront more than ever before. This doesn't mean carnivore is bad! In fact, through an adaption process a carnivore diet may the best way to reverse digestive dysfunction, and by identifying and addressing the roots of your digestive dysfunction you can reap the multitude of benefits of a carnivore diet more than ever before.
There are several common complaints from those following a carnivore way of eating that can make people wonder if this diet is right for them, or cause them to abandon it before they've experienced the benefits. Most commonly I see questions that people don't have enough appetite to eat enough or, on the other hand, that they can't get full; that they lose their appetite for fat or meat; that they struggle with diarrhea or constipation; and sometimes that they experience some weight gain. Although I'm writing this from the perspective of a carnivore diet, most of this information applies to keto diets as well.
If you see these complaints continue to crop up in online support groups, don't be discouraged from believing that carnivore is an abundantly healthy, healing diet. Keep in mind that support groups are where people go to get solutions for their complains, and they shouldn't overshadow the hundreds of benefits people are discovering every day. See my list of anecdotal reports of 150+ different benefits of a carnivore diet.
I believe most or all of these complaints can be directly tied to poor digestion, originating in the stomach, pancreas and especially the fat metabolism functions of the gallbladder.
After the digestion process starts with chewing in the mouth, food travels to the stomach where sufficient levels of hydrochloric acid are needed to begin the process of breaking down the food. Next it travels into the duodenum, the lower part of the stomach, where pancreatic enzymes are secreted to break down proteins and fats, and where bile is secreted from the liver and gallbladder to break down fats into fatty acids. These broken down food particles can then move into the intestines where nutrients and fatty acids are absorbed into the blood stream and used by the body. If the body is not able to perform any of these functions sufficiently, you can fail to receive the benefits of the micro and macro nutrients of your food, and experience symptoms directly related to poor digestion.
When I first transitioned to carnivore I was hungry a lot, and although I wasn't craving sugar, the hunger made me really want to eat food other than meat. I was able to recognize that this was probably a symptom of poor fat digestion, and I may have had issues with fat digestion my whole life. As a kid, I always avoided excess fat on meat. I would even cut the fat streaks out of bacon, while my twin sister Victoria loved fat on meat. "Kat sprat would eat no fat and Vic would eat no lean" my parents joked. I avoided hot dogs because I would throw up every time I ate one, and when my mom first introduced me to keto and made me some particularly high-fat meals, it made me nervous since I was used to so much fat making me sick. Following a ketogenic diet greatly improved my tolerance to fat, but the symptoms I experienced following carnivore indicates to me that my fat digestion probably still wasn't where it should be, especially since I can identify some family history of gallbladder problems (which doesn't mean gallbladder problems are unavoidable, but that I might be especially prone to them without treating my gallbladder appropriately).
Why this is especially a problem on carnivore
Digestive dysfunction can cause a myriad of problems for people eating any diet, probably most notably long-term nutrient deficiencies, but they can get by day-to-day with minimal symptoms by eating foods that are simple to digest. If one has pre-existing digestive dysfunction, a carnivore diet may demand attention to the digestive system for the first time.
There are several reasons the carnivore diet exacerbates digestive dysfunction. The fats found in animal products contain longer chain fatty acids than those fats from plant products and therefore require extra work to digest. Even fats like coconut oil and MCT oil, very popular in ketogenic diets, do not depend upon bile emulsification or pancreatic lipase for assimilation like animal fats, so dysfunction in teh gallbladder or pancreas won't cause issues with them the same way it will for digesting animal fats.
Additionally, protein is a much more complex molecule than that of fat and especially carbohydrates [2]. A carnivore diet generally includes higher protein than even a ketogenic diet, and these proteins require some extra work and time to digest. When proteins aren't digested properly, they are very prone to stay in the digestive system and putrify.
Just as we know that carbohydrates are a very quick, simple source of energy, they are easy and simple for the body to digest. This is one of the reasons foods like crackers are recommended for an upset stomach, and "digestive biscuits" are a popular food item in the UK.
This doesn't mean that carnivore is bad, or even bad for someone with digestive issues! In a healthy state, which can be achieved by identifying and addressing the root causes of compromised digestion, proteins and animal fats can easily be digested properly and the body can reap all the awesome benefits.
Symptoms of poor fat and protein digestion
Nausea
Along with breaking down fats, bile from the liver and gallbladder is essential for eliminating toxins. Without sufficient bile, toxins can build up and cause nausea associated with eating. Detox reactions are common with a carnivore diet as the body, finally equipped with extremely nutrient dense foods and unimpaired by sugar and phytonutrients, adjusts hormones and toxins, but I believe impaired bile production could significantly delay these detox reactions.
Floating stools, greasy or shiny stools, light or clay colored stools
It may be a good habit to start checking out your poo regularly because it can be very indicative of what's happening in your body! Any of these signs are clear indicators that your body is not digesting the fat in your diet well. Without sufficient bile, the fat you eat is passing right through you and showing up in your stools, rather than getting broken down into the fatty acids and being used for energy the way you need. Since fat doesn't mix with water, the undigested fat in stools causes them to float, and if you see shiny looking stools, you'rel looking right at the fat that shouldn't have made its way all the way through your digestive system.
Intolerance to eating fat, loss of taste for meat
This are simple, strong signs from your body that it is not digesting fats or proteins. If fats are not tolerated, the issue almost certainly resides in bile production, while undigested proteins most likely stems from low stomach acid.
Bloating, belching, gas
These are some of the main symptoms people are relieved to lose when switching to carnivore, but unfortunately for others they persist. Generally bloating and gas are simple indications that your body is struggling to digest a certain food, which is why it's commonplace to experience them when eating indigestible foods like grains and high fiber. In fact, following a carnivore diet usually increases sensitivity to plant based foods and bloating can be an immediate sign that some snuck into your diet. But if bloating, belching, or gas occurs from simply eating animal-based products, it can be a sign that this food isn't being digested. Gas builds up in the digestive system as undigested foods, especially protein, putrify and create gas.
Experiencing these symptoms within an hour of eating is a sign that this is happening higher up in the digestive system, probably as a result of low stomach acid, while symptoms an hour or more after eating are probably a sign that the undigested food is further along, associated with insufficient pancreatic enzymes.
Not hungry in the mornings
If you are following a ketogenic or carnivore diet and wake up not feeling like eating until late morning or lunch time, my first assumption is that this is simply a good sign of fat adaption, as you are hungry less often and your body is affording you the opportunity to fast a little each day. I am happy to generally not eat until about between 10 a.m. or noon each day. However, it could also be a sign that food is digesting too slowly from the night before because of insufficient hydrochloric acid and/or pancreatic enzymes.
Weight gain, resistance to losing weight
Weight gain and weight loss stalls on keto and carnivore are hot topics that are still being fully understood. I believe there are several different reasons they can occur. It's also very important to realize that these cases are the exception, not the norm, and any high-fat, low-carbohydrate diet is without a doubt the best method for losing weight. We shouldn't get concerned about keto/carnivore in general when we see these concerns on online support groups. However, impaired digestion of micro and macro nutrients can affect weight gain and weight loss through impaired satiety and metabolism.
Diarrhea, constipation
Although these symptoms are opposites, both can be signs of impaired digestion. Both have a variety of different causes. It's not uncommon for diarrhea to be a normal detox reaction as people adapt to a carnivore diet, even coming from keto. But when bile is improperly reabsorbed in the small intestine, often as a result of the walls of the small intestine being compromised by undigested food particles originating in the stomach and duodenum, the bile in the small intestine can cause diarrhea. On the other hand, undigested fat in the small intestine as a result of insufficient bile flow can stick to the walls of the small intestine and cause constipation. If diarrhea or constipation last more than four to six week after switching to carnivore, I would suspect a cause other than adaption.
Food sensitivities, such as dairy
Allergic reactions to certain foods should not be considered unavoidable, genetic phenomenon. Usually, they are a sign of impaired function in the small intestine. When improperly digested food as a result of insufficient stomach acid and pancreatic enzymes makes it to the small intestine, it can compromise the lining of the intestines and cause these undigested food particles to leak into the blood. Instead of the blood receiving the micronutrient and macronutrient byproducts it should be from the digestive system, it is not equipped to handle these large food particles and the immune system produces antigens against them, causing symptoms of a sensitivity or allergic reaction.
It makes sense that a lot of people converting to a carnivore diet are doing so because they react badly to so many other foods, indicated pre-existing digestive dysfunction, and this may be the reason so many carnivores also find it beneficial to avoid dairy, but this may not need to be the case after addressing dysfunction higher up in the digestive system.
Insatiety, binge eating
If food, especially the high-fat, quality foods you are getting on a carnivore diet, do not seem to be filling you up, causing you to constantly feel hungry or overeat, it may be because you are simply not digesting them. If pancreatic or bile insufficiency is keeping fats and proteins from being absorbed, it may feel quite simply like you are not eating these foods at all, because in reality, you're not. This means you can also look for any symptoms of a low-fat, low-protein, or even low-calorie diet, such as low-energy and nutrient deficiencies. If someone on a carnivore diet is experiencing symptoms of nutrient deficiencies, I believe it is much more likely that they are not absorbing those nutrients than that they aren't getting them from their diet. Also look for undigested food in the stools as a sign of pancreatic insufficiency.
How digestive dysfunction occurs
If digestive dysfunction is so common, how does it happen? There are a myriad of reasons.
High carbohydrate diet
Low stomach acid can easily result from the carbohydrate load of a Standard American Diet, probably as a result of the inflammation and stress on the body it causes and its affect on the microbiome.
Stress
Chronic stress, which is extremely common in our culture, puts the body in a "fight-or-flight" type response, which devotes the body's resources to life saving functions rather than, say, digestion. Over time stress can significantly impair all digestive processes, especially stomach acid levels.
Impaired gut bacteria
We hear a lot about the gut microbiome and for good reason. Keeping the digestive system working properly is one of its many important functions. Without healthy gut bacteria, stomach acid, bile production, and macro and micro nutrient absorption are impaired. There are many reasons one could end up with impaired gut bacteria- chronic stress, exposure to toxins, antibiotic usage, a history of poor diet, low exposure to environmental and dietary bacteria, and even factors occurring very early in life. Someone born via C-section or not breastfed as a baby can suffer an impaired microbiome throughout their life without some intentional intervention to make up for the important, early bacterial exposure they missed.
Use of anti-acids, Proton Pump Inhibitors
There are a variety of over-the-counter and prescription drugs that are designed to inhibit stomach acid for acid reflux relief. However, this directly inhibits the critical digestive functions of stomach acid and over time can significantly repress digestive function in general. Ironically, acid reflux is actually associated with low stomach acid, because it is not caused by a dysfunction of too much stomach acid, but by the esophageal sphincter letting acid into the esophagus, which is usually associated with low stomach acid and other digestive dysfunction.
Poor or low-fat diet
The main culprit in impaired bile function is not overuse of fats, it's a history of a low-fat diet, or a diet of poor, processed vegetable fats. Bile is produced in the liver and stored and concentrated in the gallbladder where it is secreted to help with fat digestion. When sufficient fat never triggers emptying of the gallbladder, it stays in the gallbladder and becomes sluggish and creates stones, which means sufficient bile will not be able to be secreted in the future, and could be painful.
Liver damage
Because of the liver's many important functions including those involved with digestion, impaired liver function can affect bile production as well. Sources of liver damage include low stomach acid, a high-carbohydrate diet, and toxic overloads.
What you can do
The good news is that following a keto, or even better, a carnivore diet, is the best thing you can do to help re-set these impaired digestive processes.
If your gallbladder is sluggish due to a history of low or poor fat diets, it can re-adapt with increased fat in your diet. The old, sluggish bile that is trapped inside the gallbladder will eventually get released as a high-fat diet starts triggering bile release again, and then the cleared out gallbladder will be able to function well once again. I have seen first hand accounts of people who had trouble eating fat because of gallbladder problems lose all of their gallbladder related symptoms by transitioning to a much higher fat ketogenic diet.
If a history of a poor, high-carbohydrate diet has caused low stomach acid, it will rebuild as you move to a quality ketogenic or carnivore diet. I have heard from medical professionals who use ketogenic diets with their patients that acid-reflux is one of the first symptoms they see disappear when people make the switch.
It's been posited that one of the main culprits behind pancreatic enzyme insufficiency is the blockage of pancreatic ducts by fiber [5]. It shouldn't come as a surprise then that following a low or no-fiber diet would free up these pancreatic enzymes.
Removing sugar and, although controversial, fiber, from your diet will stop feeding harmful gut bacteria allow your beneficial gut microbiome to rebuild.
All of these body processes are connected, and as they each heal, in time, the others will be able to as well. For example, sufficient pancreatic enzymes will be able to properly neutralize stomach contents and prevent unintended acidity from damaging the gut bacteria, which will therefore be able to support proper stomach acid and bile production.
The process of these digestive dysfunctions causing symptoms, and then healing, could be a reason for some of the adaption symptoms people experience when transitioning to a carnivore way of eating. However, there are several other things you can do which can give sufficient assistance during the transition, or which may be required to re-set particularly insufficient digestive processes, or are just always great practices to help ensure proper digestion.
Supplement with bile salts, ox bile, hydrocholic acid, pancreatic enzymes
The functions of the stomach, gallbladder, and pancreas can be directly supported with supplementation of stomach acid in the form of betaine hydrochloric acid, bile acid and bile salts, and pancreatic enzymes. This supplement from Thorne Research does all three together in one simple, high quality form.
Chew more
The digestion process starts in the mouth and simply focusing on chewing your food more can give your digestive process a significant head start.
Relax while eating
Likewise, ensuring you are eating in a relaxed, parasympathetic state will ensure the digestive system is unimpaired and the functions of digestive organs can heal. I recommend avoiding eating while driving, working, or any time you feel anxious, if at all possible.
Try a liver or gallbladder flush
Although I haven't experimented with them personally, a liver or gallbladder flush could be quick way to clear out and rest the bile production processes of these organs.
Eat larger, less frequent meals
Bile accumulates in the gallbladder from a steady production from the liver, but frequent eating will trigger bile to be secreted before it has sufficiently accumulated in the gallbladder. Eating less frequently will give the bile the chance to re-set and be able to handle the fat load of a carnivore meal.
Rebuild gut bacteria
By avoiding sugar and fiber and getting lots of micro-nutrients, the carnivore diet should give the digestive system great resources to rebuild, but if you suspect your microbiome needs some outside help, try a probiotic supplement or try to include carnivore friendly, fermented foods in your diet such as raw dairy products or kefir. I include some raw milk in my diet for this purpose.
References
[1] Sign and Symptoms
[2] Do Some Foods Take Longer to Digest Than Others? SF Gate. https://healthyeating.sfgate.com/foods-longer-digest-others-11622.html
[3] If You Eat Excess Protein, Does It Turn Into Excess Glucose? The Ketogenic Diet for Health. http://www.ketotic.org/2012/08/if-you-eat-excess-protein-does-it-turn.html
[4] Trouble Digesting Fats? 8 Hacks to Improve Fat Metabolism. Dr. Jockers. https://drjockers.com/trouble-digesting-fats-hacks/
[5] How to Restore Intestinal Flora and What Happens if You Don't? Gut Sense. https://www.gutsense.org/gutsense/flora.html