While there are several diets out there that have proven to be successful in treating IBS and other GI disorders, the low FODMAP diet is one of the most popular. FODMAP is an acronym standing for fermentable oligosaccharides, disaccharides, monosaccharides, and polyols, but we will discuss these categories more in depth later. Several studies suggest this diet is effective for improving symptoms of those with GI related disorders such as irritable bowel syndrome (IBS), inflammatory bowel disease (IBD), small intestinal bacterial overgrowth (SIBO), and gastroesophageal reflux disease (GERD). (1)
The FODMAP evolved from the fructose malabsorption diet, a diet used in the 90's to treat IBS. It wasn't until the early 2000's that researchers began looking more into fermentable sugars in food, and between 2004 and 2006 the first low FODMAP diet was created. Only recently has the diet become mainstream and today, several gastroenterologists recommend this diet to their patients suffering from various GI disorders.
Australian dietician, Dr. Sue Shepherd, is largely credited with the development of the FODMAP diet. After seeing such a high success rate with patients in her private practice who followed the fructose malabsorption diet, she joined the research team at Monash University in Melbourne, Australia who developed the Low FODMAP diet.
While FODMAPs do not cause the many gastrointestinal disorders we see today, avoiding them short-term has been shown to be an effective solution to improve symptoms.
A low FODMAP diet excludes foods that are high in FODMAPs, and as we said earlier, these are fermentable oligosaccharides, disaccharides, monosaccharides, and polyols. In healthy individuals with normal gut function, these carbohydrates are beneficial and act as prebiotics to increase healthy gut microbes. However, in those with digestive disorders, these foods often worsen symptoms such as bloating, gas, pain, and diarrhea. To really understand the FODMAP diet, let's break down each letter of "FODMAP" and see which foods are included.
Fermentable - This refers to the overall exclusion of carbohydrates that are fermented in the gut. These are mostly short chain carbohydrates that are poorly absorbed in the small intestine and make their way into the large intestine where they are fermented. In the large intestine, without a healthy array of microbes, fermentation causes carbon dioxide, hydrogen, and methane gas production, leading to the many unpleasant GI symptoms.
Oligosaccharides - These are short chains of monosaccharides that are larger than disaccharides, but shorter than polysaccharides. Foods high in oligosaccharides include wheat, legumes (chickpeas, black beans, and lentils), garlic, onions, beetroot, rye, Jerusalem artichoke, eggplant, cabbage, asparagus, and inulin.
Disaccharides - There are three main types of disaccharides found in the diet: lactose, fructose, and maltose. Each disaccharide is comprised of 2 of the main monosaccharides. Lactose, for example, is made up of one glucose and one galactose molecule. Lactose is the most commonly avoided disaccharide in GI protocols and is found in milk products such as ice cream, cheese, and yogurt. With all of the vegan and lactose free dairy options today, eliminating lactose isn't as hard as it once was.
Monosaccharides - The three main monosaccharides in the diet are glucose, sucrose, and galactose. As you can guess from the word "mono," this group of carbohydrates contains single carbohydrate monomers. These are often found in sweeteners and fruits such as honey, mangos, apples, watermelon, fruit juice, and dried fruit.
Polyols - These are found in certain fruits and vegetables such as blackberries, apricots, cherries, pears, peaches, plums, cauliflower, mushrooms and snow peas. They are also found in sugar alcohols such as sorbitol, isomalt, xylitol, and maltitol. Sugar alcohols are found in sugar free gum, cough drops, and diet beverages, and are strongly associated with GI symptoms.
The FODMAP Diet in Three Stages
The diet is often followed in three stages: restriction, reintroduction, and integration. The goal of this diet is to help you identify your personal trigger foods, not force you to follow a restrictive diet for the rest of your life. After all, this is a low FODMAP, not a no FODMAP diet. Another reason why it is important to introduce at least a few of these foods back into your diet is because good bacteria in the gut have been shown to diminish with long term reduction of these important prebiotics. (2) By following these steps, you will be able to identify your trigger foods and develop a gut-friendly diet that works for your body.
During this phase, all FODMAPs are eliminated. You can start looking at lists of low and high FODMAP foods and swapping out the high FODMAPs for the low FODMAPs. This phase can be followed anywhere from 4 to 8 weeks. Of course in the beginning it will be hard to know which foods are allowed, but the hard work has already done for you and you can find tons of delicious low FODMAP recipes and helpful food lists online to help you get started.
If you notice an improvement in symptoms during this phase, then you are probably on the right track and should continue with the protocol. If you do not notice any improvement and have been diligently following the protocol, then FODMAPs might not be triggering your symptoms. If this is the case, you should consult with a dietician or physician about other options.
The low FODMAP diet is not meant to be followed long term and this stage allows you to see which foods you are really sensitive to. You might notice that you do really well with lactose, but cannot handle excess fructose or polyols. Every body is unique and responds differently to the FODMAP groups.
It is recommended to reintroduce FODMAPs one group at a time over the course of 6 to 8 weeks. If you start to develop symptoms again after introducing lactose, for example, then you know this is probably a trigger for you. Introducing one food group at a time is important because if you add multiple at once, you will not be able to determine which group is triggering the symptoms.
During this stage it is recommended to keep a food journal and write down whenever you get symptoms. Journaling will help you notice patterns and identify which foods are causing your symptoms. In today's world there is an app for everything and the FODMAP diet is no different. The FODMAP app can help you track your progress and symptoms, allowing you to identify trigger foods. Of course the app is not necessary, but it is convenient.
By now you have already discovered which FODMAP foods you can handle. The purpose of this phase is to create a personalized diet plan based on your experience with the first two stages. Some foods or food groups you might be able to eat freely, while others you must eat in moderation or completely eliminate. It is only necessary to avoid the foods that you didn't tolerate well, but remember that sensitivities change and the gut can heal. You can try these foods again in a few months and see how you do.
Alternatively, you may become sensitive to foods in the following years that you handled without a problem during the reintroduction phase. You can go back to journaling or through the process again to identify new trigger foods in the future.
In a study that compared IBS patients receiving a low-FODMAP diet to those on a traditional IBS diet, it was found that the FODMAP patients had significant reduction in abdominal pain and bloating, as well as improved stool frequency (3). In addition, clinical trials found that 70% of IBS patients who reduced high-FODMAP foods had symptom relief. The diet has also been studied on IBD patients who had significant improvements in the severity of symptoms and overall quality of life compared to those patients who remained on a Western diet.
FODMAP vs SCD
The low FODMAP diet is often compared to the specific carbohydrate diet (SCD), which also reduces the amount of ingested carbohydrates. A major difference is that the SCD restricts all sugars except monosaccharides while the low FODMAP diet only restricts fermentable carbohydrates.
A few years ago when I was diagnosed with SIBO, I tried both the low FODMAP and specific carbohydrate diet (SCD). It seemed that the SCD worked better for me, but it really just depends on the person. If the FODMAPs doesn't work for you, there are several other successful GI diets such as the specific carbohydrate diet (SCD), Gut and Psychology Syndrome (GAPS), and autoimmune protocol (AIP) diets.
If you've had success with other protocols, the low FODMAPs diet might not be necessary, but if you are still struggling with GI symptoms, this diet might be the key to giving you your life back. And as we always say, it never hurts to try!
This article was written and published for informational purposes only. We are not physicians or dietitians and do not claim to be able to cure any disease or ailment. Please speak to your physician if you are experiencing medical symptoms and for health advise.