Irritable bowel syndrome (IBS) is a chronic gastrointestinal (GI) tract condition where symptoms like abdominal pain, bloating, and diarrhea, can affect everyday life. Medical intervention is important in treating IBS, but certain diets may also help. Changes in what you eat may help treat your symptoms. In fact, around 8 in 10 people with IBS find that particular foods worsen their symptoms. If you’ve been living with bloating, pain or unpredictable gut symptoms, you already know how much it can take over your day.
The low FODMAP diet involves the restriction of certain carbohydrates to improve symptoms of irritable bowel syndrome (IBS) and uncover “trigger foods”. It may not be useful or suitable for every patient with IBS but can be useful in other gastrointestinal disorders.
Understanding FODMAPs
In 2004, Australian researchers at Monash University first established the low FODMAP diet marking a significant milestone in the management of IBS-related symptoms. So the NHS didn’t actually create the FODMAP diet. FODMAP is an acronym for Fermentable Oligo-, Di-, Mono-saccharides And Polyols, encompassing specific types of carbohydrates believed to trigger GI symptoms in some people. So the official name is ‘low-FODMAP’, rather than simply ‘FODMAP’. FODMAPs are types of carbohydrates that are not completely digested or absorbed in our intestines. When FODMAPs reach the small intestine, they move slowly, attracting water. The acronym “FODMAP” stands for “fermentable oligosaccharides, disaccharides, monosaccharides, and polyols.”FODMAPs are fermentable sugars that may cause gastrointestinal distress in some people. They’re usually more difficult to digest and absorb, so they can pass through the small intestines and end up in the colon intact, where they are fermented by bacteria. This fermentation in the colon produces the gas associated with IBS symptoms like bloating, abdominal pain, and diarrhea. FODMAPs also pull water into your intestines, which may contribute to distention (abdominal swelling).
To break it down further:
- Oligosaccharides: The name oligosaccharide comes from the Greek oligos (‘a few’) and sacchar (sugar). Saccharide is just the scientific name for sugar. Chemically, every type of sugar (carbohydrate) is made up of one or more units of molecules. Oligosaccharides are a part of the fibre found in the plants we eat.
- Disaccharides: Also called a double sugar, a disaccharide is formed by two monosaccharide units, or simple sugars.
- Monosaccharides: Monosaccharides (from the Greek monos, meaning single) or simple sugars consist of one sugar unit that can’t be further broken down into simpler sugars.
- Polyols: Upon reaching the colon, bacteria ferment these sugars generating gas and chemicals that can stretch the colon walls, leading to symptoms like abdominal bloating, distension, cramping, pain, and alterations in bowel habits- all especially prevalent among IBS patients.
How the Low FODMAP Diet Works
The diet works by restricting particular kinds of carbohydrates. The low-FODMAP diet changes your microbiome by restricting the carbohydrates in your diet that bacteria love to eat. A low FODMAP diet is a type of elimination diet. It involves limiting your intake of high FODMAP foods for 4 to 6 weeks to see if symptoms improve, then gradually reintroducing foods to find out which ones worsen your symptoms.
Read also: Foods and Fibroids
The Three Phases of the Low FODMAP Diet
This package gives you a clear, structured plan to figure out what’s triggering your IBS and how to get back in control again.It’s based on the low FODMAP approach, fully tailored to your symptoms, food preferences, and lifestyle. No generic meal plans, no guesswork, just a step-by-step process that’s worked for thousands of my clients across the UK.
- Elimination Phase: Lasting 2-4 weeks, all FODMAPs are removed from the diet. Weeks 4-8 - elimination of all high-FODMAP foods: This is the elimination diet stage. The idea during this phase is to alleviate symptoms and return to a level of comfort to improve quality of life. Many clinical trials have shown a high level of success from IBS patients who reduce or eliminate FODMAP containing foods from their diet.
- Reintroduction Phase: Once the elimination phase is over and your symptoms have gone (or are at least better), you can start reintroducing FODMAP foods into your diet one at a time, about every six days. Weeks 6-10 - re-introducing individual FODMAP-containing foods: You’ll gradually re-introduce specific FODMAPs, such as lactose (by consuming some milk, for example), to see which individual FODMAPs you respond to and which you don’t. On the first days, eat one serving of a food from the FODMAP group you’ve chosen, increasing the serving size every day if your symptoms don’t come back. If they do, fast-forward to the three rest days.
- Personalization Phase: This is where you return to a regular diet as much as possible, limiting only the FODMAP foods that cause IBS symptoms. Once trigger FODMAPs are identified, patients may avoid these foods while still consuming other FODMAPs to maintain nutritional diversity. Weeks 10+ - maintenance and FODMAP personalisation: Hopefully, you’ve identified which FODMAP-containing foods you’re more sensitive to so you can design your diet and meals accordingly. Studies show (Source: PUBMED NCBI) that symptoms can continue to improve for a long time after reducing FODMAPs in your diet and even after reintroducing some of them.
Benefits of the Low FODMAP Diet
Eliminating restricting FODMAPs from the diet can significantly alleviate symptoms of IBS and other functional GI diseases, particularly in individuals who perceive a connection between their food intake and GI symptoms. A 2019 review found that around 3 in 4 people with IBS who tried a low FODMAP diet experienced improvements in symptoms. In one 2014 study, a low-FODMAP diet improved the IBS symptoms of both constipation and diarrhoea. As FODMAPs are known to produce gas and draw water into the colon, it makes sense that people with abdominal pain and diarrhoea improve on the diet, but people with constipation can also improve. The results showed that the low-FODMAP diet was 66% more likely to reduce the severity of IBS-like symptoms than a typical diet based on national dietary guidelines.
FODMAPs and the Gut Microbiome
The conditions below are all possible causes of IBS symptoms. There’s one thing they all have in common: dysbiosis (an imbalance of the microbes in your gut). Some people-for a variety of reasons-don’t produce enough digestive enzymes in their guts to break down FODMAPs before they reach the colon (Source: NCBI). Emotional and physical stress contribute to the development of IBS symptoms, and could induce FODMAP intolerance for reasons we don’t understand yet (Source: PDFS), but an unbalanced microbiome is likely to blame. One of the underlying causes (or outcomes) of IBS and IBS-like disorders seems to be an altered gut microbiota. You must take a holistic approach to your gut health.
Fructans and galacto-oligosaccharides (the ‘F’ of FODMAPs) are prebiotics: that means they feed bacteria. So restricting them may starve beneficial bacteria (Source: NCBI). Studies have also demonstrated reduced Bifidobacteria in IBS patients compared with healthy controls (Source: NCBI), which suggests that the effect of a strict low-FODMAP diet might be counterproductive. Interestingly, the low-FODMAP diet has also been shown to reduce some butyrate-producing bacteria.
Considerations and Potential Drawbacks
Opinions vary on whether you ‘have’ to start reintroducing FODMAPs after the initial exclusion phase. At Healthpath, we always try to balance managing your symptoms with tackling the root cause of them.
Read also: Diet Plan for Picky Eaters
However many constipation sufferers report the opposite effect: their symptoms get worse on a low-FODMAP diet. This could be because FODMAPs have a natural laxative effect which speeds up their digestion. It could also be because if you don’t follow the low-FODMAP diet well, you could end up inadvertently reducing fibre, which can worsen constipation. To avoid nutritional deficiencies, consider speaking with a healthcare professional or a registered dietitian before starting the low FODMAP diet.
The low-FODMAP diet starves gut bacteria. That’s how it works. The low-FODMAP diet addresses the symptoms of IBS, not the causes.
Low and High FODMAP Food Options
There are FODMAP diet lists all over the internet, and they’re all different. We recommend going straight to the source: the Monash University FODMAP web pages. Our Functional Medicine Practitioners and Registered Nutritional Therapists create each person’s food plan based on the results of their tests and their individual symptoms. They use their own expertise and experience to decide what to recommend to each client.
High FODMAP Foods to Limit
foods containing lactose, such as cow’s milk, ice cream, cheese, and yogurtcertain fruits, such as peaches, watermelon, pears, mangoes, apples, plums, and nectarineslegumes, such as chickpeas, kidney beans, and lentilshigh fructose corn syrupartificial sweetenerswheat-based breads, cereals, and pastascertain vegetables, such as artichokes, asparagus, broccoli, onions, and Brussels sprouts
Is pasta good for IBS? Pasta is typically made of wheat, a component of food that most people with IBS react to.
Read also: Vegan Diet for Diabetes Management
Low FODMAP Food Options
Low FODMAP foods you can eat on this diet may include:lactose-free milk or nondairy alternatives, such as rice milk and almond milkfruits, such as oranges, blueberries, strawberries, and grapeseggsmeats, such as skinless chicken and turkey breastsfish, such as cod and halibutvegetables, such as carrots, eggplant, green beans, pumpkin, and zucchinirice or quinoatofusoy milkhard cheeses
Rice-based pasta is a great alternative if you need to avoid gluten completely. Chickpea pasta may be suitable if you’re sensitive to gluten, but it should be limited if you need to avoid high FODMAP foods.
Some budget low Fodmap foods you can consider looking out for include:
- Potatoes
- Carrots (fresh or frozen)
- Broccoli (fresh or frozen)
- Green beans (fresh or frozen)
- Cabbage
- Cucumber
- Lettuce
- Tomatoes (fresh or canned but check there are no added garlic or onions in canned)
- Peppers
- Squash/ Pumpkin
- Chickpeas
- Canned lentils
- Canned tuna (good protein alternative)
- Rice (white or brown)
- Oats
- Peanut butter
- Rice cakes
- Eggs
- Consider chicken thighs or legs rather than chicken breast
- Firm tofu as a meat substitute
Additional Dietary and Lifestyle Considerations for IBS
Fiber Intake
A 2023 review suggests that fiber absorbs water in your gut, which helps bulken and soften your stool.This could help:regulate bowel movementsrelieve diarrhea symptomsreduce intestinal gasrelieve bloating and abdominal pain
- Soluble: This type of fiber dissolves in your intestinal tract, creating a gel-like substance to help digestion. It’s found in foods like fruit, beans, and oats.
- Insoluble: This type of fiber passes through your intestinal tract undigested, which helps bulken stool and increase digestion speed. It’s found in foods like brown rice, nuts, seeds, and grains.
The review authors note that soluble fibers are recommended for IBS, not insoluble fibers. Insoluble fibers may worsen IBS symptoms, especially if you experience excessive intestinal gas, abdominal pain, and diarrhea. The Dietary Guidelines for Americans recommends that adults consume 22 to 34 grams (g) of fiber daily, depending on their sex and age. However, more than 9 out of 10 adults fall short of this. If you’re finding it difficult to eat more fiber, consider speaking to a registered dietitian or doctor about incorporating more high fiber foods or fiber supplements into your diet.
Gluten-Free Diet
Gluten is a protein found in grains like barley, rye, and wheat that may damage the intestines of people who have a gluten-related disorder, such as celiac disease and non-celiac gluten sensitivity (NCGS). A gluten-free diet is usually recommended for people with a gluten intolerance, but research suggests that a gluten-free diet may also help reduce IBS symptoms. For instance, a 2016 study involving 41 people with IBS found that following a gluten-free diet for 6 weeks reduced symptoms. Those who followed the diet for 18 months continued to have decreased symptoms. That said, a 2018 review found that there isn’t enough high quality research to support a gluten-free diet for IBS. Consider eliminating gluten from your diet for 1 week to see if your symptoms improve, then gradually reintroduce foods to see if symptoms reappear.
- bread
- cereals
- crackers
- pastas
- some sauces
- malt vinegar
- beer
These are traditionally made from wheat, which contains gluten. However, many of these foods can be gluten-free if they’re made from ingredients like oats, rice, spelt, beans, and potato starch. You can find gluten-free versions of your favorite products in health-food stores and many grocery stores. It’s important to note that gluten-free diets are only necessary for people with celiac disease, and they may be helpful for people with NCGS and other gluten-related disorders.
Low Fat Diet
Regularly consuming high fat foods is associated with various health conditions and may worsen IBS symptoms. Healthcare professionals may recommend a low fat diet for IBS, especially if you experience frequent diarrhea. This may involve eating fewer than 27 g of fat per day. More research is needed to fully support the benefits of a low fat diet for IBS. However, healthcare organizations like the United Kingdom’s National Health Service (NHS) recommend minimizing your intake of fatty, spicy, and processed foods. This may include fried and greasy foods.
A low fat diet might involve focusing on eating the following foods:lean meatsfruitsvegetablesgrainslow fat dairy products
General Dietary Recommendations
The foods that you should eat or limit may depend on several factors, such as your dietary needs, IBS symptoms, and the foods you can tolerate. Everyone’s IBS diet will be different, and you may end up consuming a combination of different diets. It’s important to monitor your symptoms and talk with a healthcare professional before starting a new diet.
Other Lifestyle Changes
Making dietary changes may help calm the symptoms of IBS. This may include eating foods containing soluble fiber and temporarily limiting your intake of high fat foods, FODMAPs, and gluten.
- getting enough sleep
- reducing stress
- exercising regularly
- taking over-the-counter medications, such as antidiarrheals and laxatives
Holistic Approach
Like many health conditions, such as type 2 diabetes and obesity, there’s no single cause. A recent randomised controlled trial demonstrated the connection between mental health, the gut, and IBS. These studies demonstrate the connection between our psychological and physical health.
Budget-Friendly Tips for Following a Low FODMAP Diet
Check your cupboards Remember to check your cupboards, fridge and freezer before you go shopping! Sounds like an obvious thing but we’ve all been to the supermarket to find out that we already had the ingredients needed, after all. Going through your cupboards, fridge and freezer beforehand will guarantee that you only buy what you need.
Plan meals and create a shopping list Planning what you are going to eat for the week ahead will not only help you to budget during your food shop but it will also help to take the stress out of what to eat, especially when you are short on time or lacking energy. Creating a shopping list will help you to stay on track in the supermarket and not be lured by a hungry brain.
Consider cheaper cuts of meat Quite often it’s cheaper to buy a whole chicken and butcher it down yourself or the legs and thigh rather than chicken breasts. Looking at alternative beef cuts such as brisket or flank that can be slow cooked and just as tasty as steak. Quite often at the end of the day, supermarkets will reduce the price of some of their meats and these are useful to snap up and freeze for another day.
Prepare Fruit and Veg at home Buy loose fruit and vegetables items and prep them yourself. If you are able to, consider buying loose fruit and vegetables as this means you only buy what you use, creating minimal food waste. It is also cheaper per unit as you are not paying for the preparation and packaging. It’s kinder on the planet and you can compost your peelings too!
Frozen can be your friend! If you struggle with veg prep, then it may be worth considering buying frozen vegetables. They are often considerably cheaper than fresh prepped and packed veg and will last longer. Despite misconceptions, frozen vegetables don’t contain less vitamins or minerals than their fresh counterparts as they are often picked and frozen straightaway.
Bulk out your meals Cupboard staples such as chickpeas, rice and certain lentils can bulk out meals. Chickpeas, rice and lentils are great staples that last in your cupboard for ages, available either pre-prepared or dried and can be used alongside veggies to create a cost effective gut friendly meal.
Check out the ‘per unit’ costs It’s worth knowing that supermarket labels will show a ‘per unit’ price, so although a product might seem cheaper, it might not be as cost effective overall as buying a similar product with another brand. Multi-buy offers can also be tempting but make sure that you can use the product in good time, or that it will store well until you’re ready to use it.
Consider what time you shop Many supermarkets will start to lower the price of certain fresh foods that are nearing their sell by date towards the store’s closing time so it can save you money to do your food shop in the evening. This can be especially useful if you buy ready cooked meat products as delis will need to sell off the day’s produce.
Try online You can get some great offers by signing up to do your first online shop with a supermarket. Quite often, they will entice you with offers of shopping discounts to get you to sign up. It’s worth looking at all the different supermarket sites and seeing what offers are available to you.
Think seasonal Seasonal foods can often be lower in cost than foods that are grown all year round, or imported. With the autumn season upon us, now is a great time to try out recipes with squashes and pumpkins!
The ‘sniff’ test There is a difference between a ‘best before’ and a ‘use by’ date. Best before, means exactly that. A product is at its best before that date and in most cases is still safe to eat after. You can use the ‘sniff test’ on best before products as a sensory cue as to whether a food is safe to eat and this can help to extend the life of your food. For foods with a ‘use by’ date, such as fresh meat, the sniff test wouldn’t be appropriate as these foods can still contain harmful bacteria that we can’t see or smell.