The low FODMAP diet is a short-term elimination diet designed to help people identify their food triggers for conditions such as irritable bowel syndrome (IBS). However, while the low FODMAP diet is effective for managing certain food intolerances and digestive issues, there are some psychological and nutritional risks to be aware of.
Since a strict low FODMAP diet limits intake of many common foods containing fermentable, short-chain carbohydrates, it can lead to low energy, headaches, decreased gut microbiome diversity, food anxiety, and more.
In this article, we'll review seven of the most common low FODMAP diet challenges and offer tips for managing them.
What Is a FODMAP Diet
The low FODMAP diet, which was developed at Monash University in Australia, is a short-term elimination diet with evidence supporting its effectiveness in providing significant symptom relief to people with IBS.
FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols. Simply put, FODMAPs are short-chain, fermentable carbohydrates that are poorly absorbed in the small intestine and instead get fermented by your gut bacteria. This produces gas, which can feel painful for people with a sensitive digestive system (such as IBS sufferers). Certain FODMAPs also draw water into the colon, which can cause diarrhea in some people.
There are 5 different FODMAP categories:
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Fructans
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Galacto-oligosaccharides (GOS)
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Lactose
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Excess fructose
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Polyols (also called sugar alcohols)
The low FODMAP diet temporarily reduces your FODMAP intake by replacing high FODMAP foods with low FODMAP alternatives. After the initial elimination phase, foods are reintroduced one FODMAP category at a time. This enables you to pinpoint which FODMAP groups (if any) trigger your digestive issues.
A strict low FODMAP diet should not be a long-term eating pattern, but many people end up getting stuck in the elimination phase, either out of fear that their symptoms will return or because they're unsure how to reintroduce high FODMAP foods. However, as you'll soon learn, this can lead to several unintended side effects, including negative effects on your gut health.
7 FODMAP Diet Side Effects
There are many potential side effects associated with the low FODMAP diet. Before starting a low FODMAP diet, ask yourself the following questions:
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Am I moving too fast? Starting a low FODMAP diet without investigating other potential causes of your symptoms could mean you miss the root cause of your digestive problems. Ruling out other digestive disorders, such as celiac disease and inflammatory bowel disease (IBD), is crucial in ensuring your digestive symptoms are managed appropriately.
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Are my stress levels too high? The low FODMAP diet is labor-intensive, and can be complicated to follow without the guidance of a registered dietitian or other qualified healthcare professional. If you're already stressed, adding the pressure of a restrictive diet may not be appropriate.
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Am I being too hard on myself? IBS is complex, and symptoms can change from day to day, even if you're eating the exact same foods. Even if you eat a “gut healthy” or “clean” diet, you may still experience symptoms. By asking yourself whether you're expecting too much of yourself, you can determine whether you're starting the low FODMAP diet for the right reasons or if you’re using it as an excuse to eliminate more foods.
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Am I taking care of myself? While FODMAP intolerance is one common IBS trigger, other lifestyle factors such as stress, lack of sleep, and certain types of exercise can also trigger symptoms. If you're not taking care of these areas, a restrictive diet is unlikely to make a meaningful difference to your symptoms.
If you still decide that the low FODMAP diet is something you'd like to try, keep the following potential side effects in mind.
Side Effect #1: Fatigue and Headaches
One of the most common side effects of the low FODMAP diet is fatigue and headaches, especially at the beginning. This typically occurs when restricting FODMAPs leads to lower food intake and consuming fewer calories than you normally would. Calorie restriction means your body isn't getting the energy it needs to function properly, which can lead to tiredness, difficulty concentrating, and headaches.
To help minimize this side effect of the low FODMAP diet, replace high FODMAP foods with low FODMAP foods rather than simply eliminating them. It's also important to ensure your meals remain balanced by including a source of protein, a source of carbohydrates, a source of fiber, and a source of healthy fats.
Side Effect #2: Decreasing Gut Diversity
Many high FODMAP foods are prebiotics (which act as food for your good gut microbes and promote a healthy gut microbiome). When you eliminate these foods, which typically make up part of a balanced diet, you significantly reduce the amount of food available to support the good bacteria and fungi living in your colon.
While we're still learning about the differences in your gut microbiome before and after the low FODMAP diet, some research suggests that it can cause dysbiosis (an imbalance of good and bad microbes in the gut). Some research also indicates that the low FODMAP diet can reduce the amount of beneficial bacteria, particularly butyrate-producing bacteria, which may be detrimental to overall gut health.
To keep your good gut bacteria and other microbes happy and fed, consider adding some of the following low FODMAP foods, which are rich in dietary fiber, to your diet:
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Rolled oats
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Quinoa
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Cooked and cooled white rice or white potatoes (cooking and cooling certain starchy carbohydrates increases their resistant starch content)
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Carrots
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Eggplant (up to 1 cup per meal)
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Green beans (up to 15 beans per meal)
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Kiwi
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Blueberries
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Strawberries
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Chia seeds
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Ground flaxseed (up to 1 tablespoon)
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Pumpkin seeds
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Sunflower seeds
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Psyllium husk
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Partially-hydrolyzed guar gum (PHGG)
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Firm tofu
Alternatively, consider using a digestive enzyme supplement that breaks down FODMAPs in common foods that can trigger digestive symptoms. This enables you to continue including high FODMAP prebiotics while minimizing gastrointestinal symptoms such as gas and bloating.
Side Effect #3: Nutritional Deficiencies
People following the low FODMAP diet, especially long-term, also run the risk of nutrient deficiencies. While fiber is commonly lacking on this elimination diet, some people also lack calcium, iron, and vitamin B12 (especially people who are following a vegan or vegetarian diet while also implementing low FODMAP eating).
Fortunately, some small swaps can help reduce your risk of deficiencies, even if you're following a restrictive diet. Here are some tips:
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If lactose upsets your digestive system, choose lactose-free dairy products rather than avoiding dairy altogether
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Use lactase enzyme supplements when eating lactose-containing dairy products to reduce symptoms
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Include small portions of canned, drained lentils and chickpeas, which are excellent sources of non-heme (plant-based) iron. Pair them with a source of vitamin C (like citrus juice) to boost absorption
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If you're following a vegan diet, sprinkle nutritional yeast on your meals for a boost of vitamin B12
If you're concerned about nutrient deficiencies during the elimination phase of the low FODMAP diet, consider working with a registered dietitian before making dietary changes to ensure you're getting the nutrients you need.
Side Effect #4: Food Anxiety
Trying to reduce your FODMAP intake, especially for an extended period or extremely strict reduction, can lead to hypervigilance, food fears, and an unhealthy relationship with food. In severe cases, people with predisposing factors who undergo long-term dietary restrictions could be at an increased risk of developing disordered eating behaviors and increased levels of anxiety.
The worst part? Stressing about food can worsen your IBS symptoms! This is due to the gut-brain connection, or the constant two-way communication between the gut and the brain. This system includes the central nervous system (your brain), the enteric nervous system (the "second brain" in your gut), plus hormones, immune signals, and even your gut microbiome.
When you're stressed, your body shifts into "fight-or-flight" mode, diverting resources away from digestion. In some cases, this speeds up digestion (hello, bowel urgency and diarrhea), but in some cases, it slows things down, leading to constipation and bloating. Stress also increases visceral hypersensitivity, leading to normal digestion feeling painful.
Think of it this way. Fear of symptoms leads to hyper-vigilance about the foods you're eating. This hyper-vigilance leads to increased nervous system activation, which, in turn, worsens symptoms. This creates a self-reinforcing gut-brain loop.
While not everyone following a low FODMAP diet plan experiences hypervigilance around food, it's important to be aware of this possible side effect. If you're experiencing a lot of anxiety around which foods you can eat, it may be helpful to speak with a psychologist who can help you develop coping strategies for food anxiety.
Side Effect #5: Increased Stress
Even if food anxiety and hypervigilance aren't a problem for you, you may still struggle with stress associated with preparing low FODMAP meals. This is especially true if you're cooking for a partner or family who likely aren't following the low FODMAP diet.
One way to manage the stress of preparing low FODMAP meals is to use a meal-planning app or calendar to plan your meals and grocery shopping for the week. By planning your meals in advance and keeping the ingredients you need on hand, you can reduce the need to think about what to make each day. Many people find that planning their meals and grocery shopping on the weekend works best for them, but find a time that works for your schedule.
Another way to reduce stress around low FODMAP eating is to batch-cook meals and refrigerate or freeze them for later. This lets you keep low FODMAP options available when time is limited or you don't feel like cooking.
Side Effect #6: Hurts Your Social Life
While many restaurants are getting better at accommodating special dietary needs, there's no denying that eating low FODMAP makes it harder to eat out at restaurants with your friends and family.
Events like weddings, where there's a set menu, can be even more difficult to navigate. If possible, ask the host for a copy of the menu beforehand. That way, you can see what you can eat and, if necessary, eat a low FODMAP snack before attending if a lot of the menu doesn't work for you.
Digestive enzyme supplements also make eating out a lot easier, especially if you don't have control over the menu. By using digestive enzymes to break down FODMAPs, you can enjoy high FODMAP foods without stress or gut symptoms.
Side Effect #7: Not Building a Long-Term Plan
The low FODMAP diet is a short-term diet designed to get your symptoms under control and help you determine which (if any) FODMAPs are triggering your symptoms. Unfortunately, many people feel that the low FODMAP diet is the only way to manage their symptoms, leading to long-term restriction of FODMAPs.
While a low FODMAP diet is one way to manage IBS symptoms, it isn't the only way. Here are some other potential elements of a successful IBS management plan:
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Stress management: Stress can worsen IBS symptoms, so using strategies like deep breathing, meditation, or mindfulness can help reduce stress-related digestive symptoms
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Sleep hygiene: Studies show that poor sleep is associated with worsened IBS symptoms. Sleep hygiene strategies, such as limiting screen time before bed and keeping your bedroom dark and cool, can go a long way toward promoting more restful sleep
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Gentle movement: While high-intensity exercise can sometimes worsen symptoms, low-to-moderate intensity exercise promotes gut motility and gas clearance, which can help with constipation, gas, and bloating
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Adequate fiber and fluids: Fiber keeps your digestive tract running smoothly, and water helps keep that fiber moving through your intestines. Focusing on slow, sustainable increases in fiber and fluid can help your digestive system function properly
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Gut-directed hypnotherapy: An evidence-based treatment for IBS that uses guided visualization to retrain and calm gut responses
Remember, there are many different ways to manage IBS symptoms, and not every strategy will work for every person. Consider working with a healthcare provider to determine which strategies work best for you, rather than trying to DIY a care plan on your own.
Get Your Food Freedom Back with FODZYME
Dietary change, even if it leads to better symptom management, can be difficult to maintain long-term. Fortunately, there are solutions that allow you to eat high FODMAP foods while minimizing gastrointestinal symptoms like bloating and gas.
FODZYME is a digestive enzyme supplement containing three enzymes to break down FODMAPs: lactase, alpha-galactosidase, and fructan hydrolase. Breaking down FODMAPs before they reach your large intestine reduces bacterial fermentation and helps control symptoms like gas, bloating, and abdominal pain.
Using digestive enzymes like FODZYME enables you to include a healthy balance of different foods in your diet, ensuring nutritional adequacy while managing symptoms. While it doesn't contain enzymes to handle excess fructose or polyols (sugar alcohols), it can help digest foods containing lactose, GOS, and fructans.
Try FODZYME today and experience food freedom.
FODMAP Diet Side Effects FAQ
What Are the Main Symptoms of FODMAP Intolerance?
There are many potential symptoms of FODMAP intolerance, but some of the most common include:
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Abdominal cramping
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Abdominal pain
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Gas
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Bloating
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Distention
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Flatulence
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Diarrhea
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Constipation
What's the Most Common FODMAP Trigger
While different FODMAPs affect different people, the two most common FODMAP triggers are fructans and GOS. Fructans are found in garlic, onions, wheat, and certain nuts, fruits, and vegetables. GOS are found in legumes, nuts, seeds, and certain fruits and vegetables. However, while fructans and GOS are the most common FODMAP triggers, they're also important prebiotics (food for beneficial bacteria in the gut) and promote the growth of butyrate-producing bacteria. Long-term restriction of these foods should be avoided to maintain overall gut health.
How Can You Calm a FODMAP Flare-Up
If you're experiencing a symptom flare-up due to FODMAPs, there are several different strategies you can try to find relief. Some people may find that temporarily following a diet low in FODMAPs for a few days can be helpful. Herbal remedies such as peppermint oil, which can help calm digestive tract contractions, can also be effective. Finally, a heat pack applied to your abdomen for 15 to 20 minutes can soothe abdominal pain and cramping.
How Do I Get Started With a Low FODMAP Diet?
The initial phase of the low FODMAP diet typically lasts from 2 to 6 weeks and involves replacing high FODMAP foods with low FODMAP alternatives. Then, over the course of 8 to 12 weeks, you will slowly reintroduce FODMAPs one FODMAP category at a time, which enables you to determine which FODMAP groups you're sensitive to. Once you've identified your triggers, you move on to the maintenance phase, which involves gradually including more higher FODMAP foods as tolerated.
What Should I Do Once I've Learned My FODMAP Triggers
Remember, the ultimate goal of the low FODMAP diet is to identify your triggers so you can liberalize your diet as much as possible. Once you've determined your triggers, you can go back to eating high FODMAP foods you tolerated. For foods that do cause symptoms, consider taking digestive enzyme supplements like FODZYME when you eat your known trigger foods (like onions and garlic) to reduce gastrointestinal symptoms.