Knowing what to eat when you have irritable bowel syndrome (IBS) is challenging. Since no two people are alike, there is no one-size-fits-all IBS diet recommendation.
People with diarrhea-predominant IBS (IBS-D) may not have the same triggers as those with constipation-predominant IBS (IBD-C). Even within each subtype, identifying and avoiding the foods that set off IBS symptoms will be different for everyone.
With that said, there are several diet approaches that appear to provide relief for the various IBS subtypes. Some may require tailoring to ensure sustained relief, but, with a little patience and some trial and error, you’ll eventually find the eating plan that can help keep your IBS symptoms under control.
This article discusses what to eat to manage IBS. It explains common recommendations for an IBS diet, including a low-FODMAP diet and gluten-free diet.
How to Avoid FODMAPs to Lessen IBS
Dietary Recommendations for IBS
IBS is a complex disease, so there’s not just one ideal diet plan. Most clinicians recommend a two-stage approach:
- First, stick to a regular meal pattern while reducing insoluble fiber, alcohol, caffeine, spicy foods, and fat. Make sure to get regular exercise and drink plenty of fluids to avoid dehydration.
- If these interventions don’t provide relief, the next step would be to try a low-FODMAP or gluten-free diet. This should be explored under the guidance of a qualified healthcare professional.
Additional steps may be needed if you still have symptoms. This could involve identifying and avoiding food triggers, including those that cause allergies or food intolerances. Check with a dietitian or nutritionist to make sure you’re meeting your daily nutritional goals.
Low-FODMAP Diet for IBS
FODMAP (fermentable oligosaccharides, disaccharides, monosaccharides, and polyols) are short-chain carbohydrates found in many foods. They tend to ferment and increase the volume of liquid and gas in the small and large intestines.
Excessive consumption of FODMAPs can lead to flatulence, bloating, and abdominal pain. Given that these are hallmarks of IBS, it makes sense that eliminating high-FODMAP foods would help prevent or ease these symptoms. The diet can be challenging, as many common foods are high in FODMAPs.
There are five types of FODMAPs:
- Fructans (found in wheat, onions, garlic, barley, cabbage, and broccoli)
- Fructose (found in fruit, honey, and high-fructose corn syrup)
- Galactooligosaccharides (found in legumes and beans)
- Lactose (found in milk and other dairy foods)
- Polyols (found in stone fruits, sweet potatoes, apples, and celery)
A low-FODMAP diet is designed in two phases as part of an elimination diet:
- Phase 1: Foods high in FODMAPs are restricted for a short period of time, generally between three to six weeks.
- Phase 2: The foods are reintroduced into the diet, one FODMAP type at a time, to assess your tolerance to each.
The American College of Gastroenterology (ACG) recommends this be done under the guidance of a properly trained gastrointestinal nutritionist. If that’s not possible, they urge healthcare providers to give you high-quality materials to help guide you through it in a medically responsible way.
Studies found that approximately 75% of people with IBS who attempted a low-FODMAP diet experienced significant symptom relief.
Gluten-Free Diet for IBS
Many people with IBS will report an improvement in symptoms when they eliminate gluten from their diet, even if they do not have celiac disease. Gluten is a protein found in foods that contain cereal grains such as wheat, rye, and barley.
The notion that gluten plays a role in IBS is subject to debate. On the one hand, there are scientists who contend that IBS is a form of non-celiac gluten sensitivity, a poorly understood disorder similar to celiac in which gluten triggers adverse gastrointestinal symptoms. Others argue that the FODMAP fructan, rather than gluten, is the problem.
If a low-FODMAP diet is unable to provide relief, a gluten-free diet may be attempted to see if your symptoms improve. If so, gluten intake may be increased to see how much of the protein you can reasonably tolerate. This may allow you to eat a wider range of foods without such strict dietary controls.
A gluten-free diet is defined as having less than 20 parts per million (ppm) of gluten per day. A low-gluten diet generally involves less than 100 ppm of gluten.
Before starting a gluten-free diet, it is important to test for celiac disease by serological testing, Transglutaminase IgA antibody, and total IgA levels. If patients have low IgA levels (approx 2-3% of the population), then the Deamidated gliadin peptide IgG antibody is used for screening. If the serological tests are equivocal, then genetic testing is the next step.
If your symptoms do not fully resolve with a low-FODMAP or gluten-free diet, your healthcare provider may investigate whether you have specific food allergies or food intolerances. Such a diagnosis may require testing and the input of an allergist. Your diet, then, would need to be further adjusted accordingly.
Foods for IBS-C
To ease chronic IBS-associated constipation, you will almost inevitably need to eat more fiber. It is important to increase the intake gradually to allow your body time to adjust. Generally speaking, soluble fiber is better tolerated by people with IBS than insoluble fiber.
You will also need to eat foods that contain healthy polyunsaturated or monounsaturated fat. Foods that are high in saturated fat and sugar are known to promote constipation.
Whole-grain bread and cereals
Fruits (especially apples, pears, kiwifruit, figs, and kiwifruit)
Vegetables (especially green leafy vegetables, sweet potato, and Brussels sprouts)
Beans, peas, and lentils
Non-fat milk (in moderation)
Yogurt and Kefir
Fish (especially fatty fish like salmon and tuna)
Seeds (especially chia seed and ground flaxseed)
White bread, pasta, and crackers
Fast or fried foods
Baked goods (cookies, muffins, cakes)
Full-fat cream and dairy (including ice cream)
Alcohol (especially beer)
Foods for IBS-D
If your IBS symptoms involve diarrhea, it is best to stick with bland foods, especially if your symptoms are severe. Fatty, greasy, or creamy foods are to be avoided as they can speed up intestinal contractions, causing cramping and runny stools.
Avoid insoluble fiber, which draws water from the intestine, making stools loose or watery. Though you should make every effort to eat fruits and vegetables, it is best to limit your intake of fiber to less than 1.5 grams per half-cup during acute episodes.
White bread, pasta, and crackers
Whole grains (unless you are gluten intolerant)
Lean fish (like halibut, flounder, and cod)
Boiled or baked potato
Beans, peas, and legumes
Rice milk, almond milk, or coconut milk
Low-fat lactose-free milk
Low-fat probiotic yogurt (in moderation)
Unsweetened clear fruit juice
Hard cheeses (in moderation)
Fast or fried foods
Foods high in sugar (e.g., baked goods)
Fatty meats (e.g., bacon and sausage)
Processed meats (e.g., hot dogs and lunchmeat)
Sardines and oil-packed canned fish
Cruciferous vegetables (e.g., cauliflower, broccoli, cabbage, and Brussels sprouts)
Salad greens and raw vegetables
Bean, peas, and legumes
Milk and dairy products (e.g., butter and soft cheeses)
Sweetened juices and fruit nectars
Artificial sweeteners (sorbitol and xylitol)
Once you find the right diet for you, it’s important to stick with it. Unlike some eating plans, IBS diets are generally intended for a lifetime and often require you to make significant lifestyle changes.
This may not only include avoiding alcohol, caffeine, and fatty foods, but also regular exercise to normalize bowel function and lose weight. A diet alone can often fall short in controlling IBS symptoms if you remain inactive and/or overweight.
At present, there is no indication that a low-FODMAP diet or gluten-free diet can be used on an “as-needed” basis to treat acute symptoms. With that said, you may want to increase your intake of certain foods if you have diarrhea or eat extra prunes or bran on days when constipation symptoms are acute.
Many people with IBS find that eating smaller, more frequent meals places less stress on the digestive tract than sitting down for three large meals. Doing so ensures that the bowels move regularly and gently, as opposed to suddenly being full and then having nothing in them for five to six hours straight.
However, some people with IBS-D may be advised to eat a substantial breakfast or sip coffee first thing in the morning to stimulate a bowel movement (referred to as a gastrocolic reflex). Doing so may keep you regular throughout the day. Taking a short walk after eating also helps, as can sitting in a chair during meals rather than slouching on the sofa.
How you eat plays a role in whether you experience IBS symptoms or not. Eating slowly with concerted pauses between bites can reduce the amount of air you swallow during a meal.
The same applies to eating on the run, sipping drinks through a straw, and chewing gum, each of which introduces air into the stomach and increases the risk of gas, bloating, and stomach pain.
When embarking on an IBS diet, the number-one rule is to avoid any deep-fat frying. As much as you may enjoy French fries, donuts, or fried chicken, these types of foods are banned whether you have IBS-C or IBS-D.
Instead, grill, roast, or pan-fry meats with as little oil as possible. One trick is to spray oil onto the meat rather than pouring oil into the frying pan. You can also lightly sear meat, chicken, or fish to get a nice crust and then finish it off in a hot 425-degree oven for a few minutes, just like restaurants do. An air fryer may also be a good investment.
Steaming vegetables make them more digestible, especially if you are prone to diarrhea. If you love salads but find them hard to digest, look for cooked salad recipes (like a Mediterranean Heart of Palm Salad or a Grilled Eggplant Salad). Peeling vegetables, tomatoes, and fruit also makes them more digestible.
Instead of salad dressings or sauces, use a squeeze of lemon or lime, some chopped fresh herbs, or a mild tomato or mango salsa to flavor foods.
To reduce gassiness from canned beans, rinse them thoroughly and allow them to soak in a bowl of cold water for 30 minutes. If starting from scratch, soak the dried beans twice—first in hot water for a couple of hours, then in cold water overnight—before cooking them slowly in fresh water until very soft.
Some people claim that adding ground ajwain (a type of caraway) or epazote (a Mexican herb with a pine-like aroma) can dramatically reduce the gassiness of beans as they cook. While there’s no proof of this, it can’t hurt to try it.
Diets as restrictive as the low-FODMAP and gluten-free diet can be difficult to sustain. They require a commitment on your part as well as buy-in from your family. By focusing on the benefits to your health and well-being rather than the foods you’re deprived of, you can learn to cope with the challenges of the diet and begin to normalize IBS in your life.
Both the low-FODMAP and gluten-free diets have their benefits and shortcomings. Both are considered safe in adults as long as the daily recommended intake (DRI) of protein, carbohydrates, and nutrients is met. With that being said, nutritional deficiencies are common due to the diets’ lack of whole grains, dairy, and other important food groups.
For the most part, the diets can be used safely in people with diabetes and hypertension (high blood pressure) since many of the foods are considered beneficial to these conditions.
Both diets require a period of adjustment, during which time you may experience short-term side effects like tiredness or bloating. Most of these resolve over time, although some (like food cravings) take a concerted effort to control. The greater concern is the long-term impact of these diets on your health.
Nutritional demands increase during pregnancy, and following these diets may not meet your dietary needs. Both low-FODMAPs and gluten-free diets eliminate wheat and may be low in:
All of those nutrients are necessary for normal fetal development. While prenatal vitamins can help overcome these deficiencies, these shortcomings demonstrate how detrimental these diets can be if left unsupervised.
The above-mentioned nutrient deficiencies are one of the reasons why low-FODMAP and gluten-free diets are used with extreme caution in children who otherwise need a healthy, balanced diet to ensure normal growth and development.
In children, a low-FODMAP diet is only used with a confirmed IBS diagnosis and a lack of response to conservative therapies. Similarly, a gluten-free diet should only be used in children who are positively diagnosed with celiac disease or non-celiac gluten intolerance.
Risk of Eating Disorders
Beyond the aforementioned risk of nutritional deficiencies, some scientists are concerned that restrictive diets like these (particularly those used without medical motivation) can lead to disordered eating. This was evidenced in part by a 2017 study from Sweden in which young girls with celiac disease were 4.5 times more likely to have anorexia than those without.
Altered Gut Flora
Others question whether the long-term use of restrictive diets might permanently alter the gut flora, increasing the risk of bowel infection.
There is even evidence that certain food restrictions can affect heart health. A 2017 study in the BMJ Clinical Research suggested that the avoidance of gluten in people without celiac disease increases the risk of cardiovascular disease due to the lack of beneficial whole grains.
Sustainability and Practicality in the Real-World
One of the common drawbacks to the low-FODMAP and gluten-free diets is the impact they have on one’s social life.
A 2018 review of studies in Gastroenterology & Hepatology reported that persistent dedication to a restricted diet contributes to increased rates of social isolation as well as feelings of anxiety and inadequacy if adherence to the diet falls short. Luckily, there are ways around some of these concerns.
Unlike previous decades, gluten-free dining options have increased considerably, making it easier to dine out with friends, families, and work associates. Some casual dining chains have even gotten in on the act.
Even if a restaurant isn’t gluten-free or doesn’t have low-FODMAP options, you can check the online menu before you arrive and usually find something you can eat. Some restaurants may even make accommodations if you call far enough in advance and advise them of your dietary concerns.
Home cooking has obvious health advantages but is especially valuable if you have IBS, as it provides you full control over your ingredients. The advent of low-FODMAP and gluten-fee cooking has inspired food bloggers to post their favorite recipes online, many of which are good for the family as well as friends.
For those who are too busy to cook, there is a growing number of meal kit delivery services that specialize in gluten-free foods as well as several that have started to offer low-FODMAP options.
Another issue is the typically higher cost of gluten-free and low-FODMAP foods at grocery stores.
A 2018 study from the United Kingdom reported that gluten-free foods were 159% more expensive than their regular counterparts. This can make the cost of gluten-free eating prohibitive (although the costs can usually be reduced by avoiding packaged foods and eating real foods prepared at home).
By contrast, low-FODMAP packaged foods are relatively difficult to find, with only a handful of specialty producers (Rachel Pauls Food and Fody) offering snacks, spices, dressings, and soup bases. These also tend to be quite costly.
Support and Community
It is hard to go it alone if you decide to start an IBS diet. As much as you may want to avoid “burdening” your family with your decision, you may find it harder to cope if you isolate them from what you are going through.
Instead, make them a part of the process by educating them about what IBS is and how the diet is meant to help. In some cases, it may open the door to making positive changes to your entire family’s diet, rather than ones that only benefit you. Looping them in also means you are more likely to gain their support and less likely to be sabotaged by those who might dismiss the diet as a “fad.”
If you are struggling to cope with the diet, let your healthcare provider know so that adjustments can be made. You should also seek support from others who have experienced what you are going through.
There are plenty of IBS support groups on Facebook as well as community forums offered by the non-profit IBS Patient Support Group. Your healthcare provider may also know about live IBS support groups in your area.
There are even low-FODMAP apps and gluten-free apps that can help keep you on track if you need support, encouragement, or inspiration.
The relationship between food and IBS is a complex one, but there are changes you can make in both how you approach meals and the foods you choose to eat. A smart eating strategy can dovetail nicely with the medical treatment you receive from your healthcare provider to relieve and control IBS symptoms.