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Guest Blog: Everything you need to know about SIBO by Katie McKersie

Guest Blog: Everything you need to know about SIBO by Katie McKersie

Hey everyone, 

My name is Katie & I am a Functional Diagnostic Nutritionist who runs a virtual women’s health practice focusing on hormones and gut health called Holistico! I help women all over the world get their periods back, overcome PCOS, recover from birth control, beat the bloat, stop their acid reflux, heal their metabolism, clear their skin & so much more. You can find me over at or on Instagram @holistico & other social media platforms @holisti_co. Feel free to get in touch as I would love to chat with you! 

I am super excited to be teaching you all about SIBO during this blog takeover! It is a condition that I have dealt with myself in the past and I see so often in my practice. The majority of my clients suffering from skin conditions and/or IBS have SIBO present. It is never the whole picture as SIBO is not really a root cause per say (keep reading to find out why) but it’s a crucial step you need to address in your health journey. 


Let’s dive in! First off, what is SIBO and what are the typical symptoms of SIBO?


SIBO stands for small intestinal bacteria overgrowth and occurs when there is a build up of either good and/or bad bacteria in the small intestine. The majority of our bacteria should always be living in our large intestine. The two most prominent symptoms I see are; excessive gas & chronic bloat. 


9 times out of 10 if you have any kind of SIBO you will have one of those symptoms. However, I have had clients in the past that present with more of the secondary symptoms like; 

  • constipation
  • diarrhea
  • nutrient deficiencies (A, D, E, K)
  • abdominal pain 
  • acne, rosacea & other skin conditions 
  • chronic fatigue
  • anxiety and/or depression
  • undigested food in stool
  • dark under-eye circles 
  • rashes 
  • frequent nausea 
  • weight gain or weight loss
  • acid reflux
  • brain fog
  • joint & bladder pain 


If you are suffering with any of these, it is important to work with a knowledgeable practitioner that you trust as SIBO is a very serious condition and is complicated to eradicate on your own. If you want to schedule a free call to see how I can help you, I would love to talk: I also posts lots of amazing gut health tips on my blog:


Some of you may have heard of a less common condition called SIFO which is small intestinal fungal overgrowth that can present with similar symptoms. Luckily, most comprehensive SIBO protocols will address this as well. 


There are 3 types of SIBO (not just two): 

  1. Hydrogen Dominant (phase 1)- This is the most common type and is associated more with diarrhea, abdominal pain and nutrient deficiencies 
  2. Hydrogen Sulfide Dominant (phase 1.5)- This is the most undiagnosed type and is associated with gas that has a rotten egg smell, histamine intolerance, joint pain as well as altering constipation & diarrhea
  3. Methane Dominant (phase 2)- This is the least common type and is associated more with constipation, acid reflux, weight gain and brain fog 


I like to explain these types in phases. It’s starts with FODMAP’s (fermentable, oligosaccharides, disaccharides, monosaccharides and polyols) which are short chain carbohydrates that are poorly absorbed by the small intestine. When a slow metabolism is present, these will be slowly digested and act as fuel for the bacteria in the small intestine. When bacteria ferments it produces hydrogen gas which we call Hydrogen Dominant SIBO or phase 1. Methane dominant SIBO is one step further because the hydrogen gas will then feed the archaea (anaerobes) which will produce methane gas as a byproduct of that. This means that with methane dominant SIBO, it’s not necessarily the bacteria causing the high levels of methane gas, it’s more the methane producing archaea which is why I like to call phase 2. With hydrogen sulfide dominant SIBO, it’s important to know that this is a totally different gas than Hydrogen. This is when sulfate reducers (bacteria) feed on the hydrogen gas produced by other bacteria to produce hydrogen sulfide gas which is why I call it phase 1.5. 


It can be hard to tell which type someone has as all of these types are likely to present with bloat and/or abnormal gas. You also can have more than one type! The “gold standard” for testing SIBO is a breath test but I don’t usually find these super beneficial and here is why: 


  1. They are expensive and not 100% accurate leading to false accusations and hope
  2. They usually are only testing hydrogen dominant or methane dominant SIBO. It will come back normal if you have hydrogen sulfide SIBO leaving many people confused and discouraged
  3. It does not tell us the root cause of why SIBO has occurred in the first place 
  4. Many antibacterial agents used to eradicate SIBO are multi-faceted and will take care of all types present
  5. It is easy and fairly quick to identify SIBO through specific nutritional changes 


With my clients, I like to run both a GI Map and HTMA test while starting a metabolically supportive lower fodmap protocol. Here is more info on these two tests: The GI map will give us a lot of insight if SIBO is present along with other pathogenic bacteria, parasites, fungus, viruses and more. It also tests immunity, detoxification, inflammation and mucosal barrier health which are all critical pieces to the SIBO puzzle. The HTMA is a comprehensive mineral test to give us more insight into detoxification, adrenal function, nervous system balance and most importantly metabolic health. A poor metabolism at the cellular level is truly the root cause of SIBO because it is going to slow down your entire gastrointestinal tract allowing this bacteria to ferment and SIBO is very much a motility issue. 


This is exactly why I don’t recommend cutting all sugar/carbohydrates or going on the typical “Low FODMAP” diet because it is extremely suppressive to your metabolism. After all, how can you heal a body that is restricted from its primary source of fuel (glucose)? I have watched other people try the Low FODMAP diet and although their SIBO symptoms are temporarily suppressed a lot of the time, they usually return with a vengeance because the root cause was never addressed. Instead, I recommend doing a modified lower FODMAP diet temporarily that still includes a variety of micronutrients and a lot of metabolically supportive foods. This does not involve cutting out any macro but you do need to be super strategic with your nutritional choices. For example, raw honey and sweet potatoes will feed SIBO whereas pure maple syrup and white potatoes will not. Usually within a couple weeks of this modified diet, many of my clients feel a massive relief of symptoms which is how we know SIBO was present. Typically, it takes my clients and I about 8-12 weeks to eradicate and then we focus heavily on rebuilding their metabolism and restoring their mucosal barrier so they do not run into digestive problems again in the future. My metabolically supportive lower FODMAP meal plans and grocery lists coupled with specific binders, biofilm disruptors and wild anti-bacterial herbs have proven to be extremely effective over and over again. Although, some clients come to me in a very under-nourished and depleted state so we need to take a step back to balance their minerals and support their detoxification pathways as well as immune system before doing any sort of eradication. I never recommend starting a SIBO or any gut protocol without first ensuring you are having at least one full bowel movement every single day because we want to be excreting these toxins regularly, not re-circulating them. 


If any of this has resonated with you, I hold SIBO group programs called “Trust Your Gut” twice a year where I work with a small group of women to help them get rid of their SIBO for good! Many of these women have been diagnosed with IBS and didn’t even realize they had SIBO. This program lasts 3 months and is about half the price of what it is to work 1:1 with me yet just as valuable if you are suffering from gut distress. Here is what other women like you have been saying: 


“Katie is by far the best nutritionist I have ever worked with and I can honestly say I have worked with many of them” says Chloe Lapenat.


“Katie taught me how to get rid of my bloating for good. I no longer see blood in my stool and I don’t vomit mucus every morning” says Stefanie Dubois. 


“I have suffered from celiac disease for years and always assumed it would be something I lived with for the rest of my life. Katie looked at the big picture to figure out the root causes of my issues instead of fixing it with a band-aid approach” says Julia Somerville. 


“I have dealt with brutal stomach pain, heartburn and bloating for years and all I was ever told is that I have IBS. I didn’t know I could possibly have H Pylori and SIBO until I found Katie” says Sylvia Martin. 


“After a few months I saw drastic improvements in my skin that I never thought I could achieve without medication” says Jessica Garcia. 


You can get more info and secure your spot in the next program here: as it fills up quick! Please reach out if you have any questions. Looking forward to e-meeting you soon and tackling your chronic health issues together! 



Katie McKersie

Hormone & Gut Nutritionist 



M: 416-737-5121

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