Could this be the cause of your bloating and other embarrassing symptoms?

You put on that pair of pants in the morning, buttoning them around your waist with inches to spare. That’s a great feeling isn’t it? But as the day goes on, the waist band feels tighter and tighter. By the end of the day, you have a choice, either unbutton the pants or risk hitting someone in the eye with a flying button. This was an all too familiar occurrence for me. What’s going on?

The microorganisms are in the wrong place

Angela Larson wrote an informative article in Charm, May 2016 called “Trust Your Gut.” It was about how important the friendly microorganisms that live in our gut are to our health. You can think of our gut as a long tube starting from our mouth and ending with the colon. About 70 percent of the microorganisms that Angela was discussing live in our colon. As we move up through the digestive tract, from the colon to the small intestine to the stomach, the numbers decrease substantially.

But what if you have too many of these microorganisms living in your small intestine that shouldn’t be there? This condition is called small intestinal bacterial overgrowth (SIBO). Although controversial, many researchers and clinicians believe that SIBO is one of the causes of irritable bowel syndrome (IBS). Due to variations in population differences and diagnostic criteria for both IBS and SIBO, there is a huge range of people who have IBS and SIBO, from as little as 4 percent to as high as 84 percent. SIBO is what was causing my pants to pop!

How do you know if you have SIBO?

There are two ways to measure SIBO. One is the jejunal aspirate, which directly quantifies the amount of bacteria living in part of the small intestine. It is invasive and usually only done in a research setting.

There is a non-invasive method called the breath test. This measures the amount of gas produced by the bacteria that is excreted through the lungs after ingesting a special type of carbohydrate. This test is somewhat controversial but is becoming more common in clinical practice.

Some clinicians will treat the SIBO based on symptoms alone, if the symptoms are gone after treatment, then it may have been SIBO.

What are the symptoms?

One of the top symptoms of SIBO is bloating. We’re not talking about a little bloat. The SIBO bloat looks like you are 6 to 7 months pregnant. My children would often ask “Mommy, do you have a new baby in your belly?”

Here is what happens. The overgrowth of bacteria in your small intestine love carbohydrates. You wake up in the morning after a nighttime fast and have a comfortable, quiet, flat stomach. But as you eat throughout the day, they eat throughout the day, producing lots of gas as a byproduct. This gas can get trapped throughout your small intestine, causing bloating, which gets worse as you continue to eat throughout the day.

Other symptoms include flatulence (the gas either exits through your lungs or can make its way out through the other end). Diarrhea and abdominal pain are also common symptoms.

If the SIBO is severe, it can lead to an inability to absorb nutrients, causing weight loss and malnutrition. There are also other symptoms outside of the gastrointestinal (GI) tract that are associated with SIBO, ranging from rosacea (a skin condition) to restless leg syndrome.

You can’t just take a pill

SIBO can be treated with non-absorbable antibiotics, and one research study found that specific herbal antimicrobials also were effective. However, it isn’t as simple as just taking a pill.

Unfortunately, for about 70 percent of the cases SIBO can come back after treatment. This is because it is a symptom of something else, more like multiple something elses.

Finding the underlying cause(s) takes a lot of detective work for both the patient and the clinician. The mother of all underlying causes for SIBO is impairment in the migrating motor complex (MMC). This complex is known as the cleansing waves or housekeeper of the GI tract. It is responsible for sweeping out bacteria from the small intestine in between meals. In many cases of SIBO, the MMC isn’t working properly and we have to figure out why it’s impaired.

Control your symptoms with diet

If you have SIBO or IBS for that matter, diet can play a huge role in helping you control your symptoms. There are many SIBO diets and the premise of them all is to restrict certain carbohydrates that feed the bacteria in your gut.

I wrote a free guide on “What’s the Right SIBO Diet for You?” that you can download from for more information on the different diets.

For the purposes of this article, I’m going to discuss the most popular and well researched diet in the IBS population that also works well for SIBO. This diet is called the FODMAPs diet. It is an acronym that stands for fermentable oligo-, di-, mono-saccharides and polyols. Now that’s a mouthful!

FODMAPs are categorized based on their chemical structure. These categories include:

1. Excess fructose in excess of glucose: sweeteners, certain fruits and vegetables

2. Lactose: found in dairy products

3. Fructans: found in wheat, rye, vegetables and many other foods

4. Galactooligosaccharides (GOS), also known as galactans: found in legumes

5. Sugar polyols: sweeteners, certain fruits and vegetables

There are two approaches to starting the diet: 1) eliminate all of the high FODMAP foods or 2) eliminate foods from just one category.

If you go with this approach, my suggestion would be to start with foods in the lactose category, which is one of the biggest FODMAP offenders.

For a sample list of high FODMAP foods, visit: or download the Monash University Low FODMAP Diet App.

Everyone has difficulty digesting some of these FODMAPs, whether or not you have IBS or SIBO. It’s just that some of us have more problems with these foods than others, and eating them can cause a lot of pain, bloating and other uncomfortable symptoms.

Diet is your first step

The sooner you can find a diet approach that works for your particular SIBO, the quicker you can start feeling better and be on the road to recovery.

But diet is just the first step. There are many more steps that need to be taken to heal from this condition or from any gut issue for that matter. Being on a restrictive diet for long term is not good socially, psychologically and may even hurt the bacteria in your colon.

If diet only treats the symptoms, how do get rid of SIBO?

The answer to this question is this — you must find the root cause(s). In other words, why do you have SIBO to begin with? You can take antimicrobials and find the diet that controls your symptoms, but until you find the root cause(s), it will keep coming back. From my experience and training I’ve seen that most people have an average of three to four root causes.

In conclusion, SIBO is becoming more recognized by the medical community as research is exploding in this area. It can be associated with IBS and in some cases, is the cause of IBS. Symptoms include bloating, gas, diarrhea and abdominal pain.

Treating SIBO is important, but you also must find the underlying cause. If you have gut problems that are keeping you from enjoying your life, then please visit for a free 30 minute consultation.

Darla O’Dwyer is a registered dietitian and holds a Ph.D. in nutrition and food science. She is director of a dietetics graduate program at a small university and owns an online nutrition consulting business ( where she helps people heal from SIBO and other gastrointestinal disorders.