Low FODMAP Diet: A Simple Guide to Managing Digestive Symptoms

What Is the Low FODMAP Diet?

The Low FODMAP diet seems like just another made-up gut health diet fad from social media, but Monash University's development of the diet has helped improve symptoms of those with irritable bowel syndrome (IBS) for decades. 

The list of high FODMAP foods is actually quite long, but they are mostly in fruits, vegetables, and some dairy products. In grains, they are less common, with only wheat, rye, and barley (i.e. gluten-containing grains) falling into the high-FODMAP category.

This all may sound scary, but with the help of a dietitian, a FODMAP elimination diet can help one manage these symptoms. An eating plan like this is temporary, unlike something like a gluten-free diet, and the purpose is to identify foods that cause symptoms so that one can avoid them. It can take quite a bit of restriction and be tedious in terms of the timeline, but it’s meant to be approached as a discovery process to provide you with an eventual list of “safe foods” to make eating less anxiety-inducing.

Breaking Down FODMAP: What These Foods Actually Are

FODMAP is an acronym that stands for Fermentable Oligosaccharides Disaccharides Monosaccharides and Polyols, four types of special carbohydrates that certain people have trouble breaking down, especially if their gut is inflamed from conditions like IBS. Some examples of these carbohydrates include the lactose in milk (disaccharides), the sweeteners in sugar (polyols), and the raffinose in beans (oligosaccharides).

FODMAPs cause issues during digestion because they tend to pull water into the gut and often are too small to absorb in the small intestine. The extra water can cause diarrhea and discomfort, especially for those with IBS who can’t handle the stretching of the intestines the extra water can cause. When these sugars travel past the small intestine to the colon without absorption, they are broken down by the bacteria in our gut, which can produce bloating, gas, and pain. This is where the term “fermentable” comes from. 

Who Should Try a Low FODMAP Diet?

If you often experience symptoms like abdominal pain, bloating, excess gas, diarrhea, or constipation after eating, you may have a sensitivity to FODMAPs. If you have not been diagnosed with any sort of bowel condition, talk to your doctor about getting tested for a diagnosis before taking on a digestive health diet, especially without professional supervision. 

The FODMAP elimination is most useful for those with IBS, SIBO, or other disorders like celiac disease that isn’t responding to a gluten-free diet or other IBS diet. However, it’s important to note that, even though you follow a low FODMAP meal plan doesn’t mean you should expect dramatic improvements. About 75% of those with IBS see a reduction in symptoms. 

The low FODMAP meal plan is not recommended for those with a BMI below 18.5, people with a history of disordered eating, or children due to the restrictive nature of the diet. If you fall under these categories, it’s critical to seek out a physician and a registered dietitian for guidance to navigate the diet safely. 

How the Low FODMAP Diet Works: The Three Phases

The Low FODMAP diet must be approached slowly and gradually to be effective. Remember, it’s LOW FODMAP diet, not a NO FODMAP diet as there may be foods that are triggers that you can eat, but below a certain threshold. That’s what participants find out during the three-step FODMAP diet phases which typically take anywhere between 8 and 14 weeks to complete. 

Phase 1: The Elimination Phase (2-6 Weeks)

This is the hard part as it requires the removal of all high FODMAP foods to result in solely low FODMAP eating. This means only having foods in the diet that are low in FODMAPS compared to high; some examples being choosing pineapples over apples or almond milk over cow’s milk. The purpose of the elimination phase isn’t to identify triggers just yet, but to give the digestive system a break from triggers and avoid unpleasant symptoms. 

If those following the diet are truly sensitive to FODMAPS, then a low FODMAP meal plan should elicit symptom relief within 2-6 weeks. Do not adhere to the elimination phase longer than 6 weeks. If symptoms are not improving by this time, talk to your healthcare provider. 

Phase 2: The Reintroduction Phase (6-8 Weeks)

This is where the “meat and potatoes” of the FODMAP elimination diet lives. It involves carefully and systematically testing high FODMAP foods in isolation over a course of 3 days. It is very important to not mix the foods being tested with other carbohydrates and risk recording one food for elimination that could be perfectly safe to eat. 

If symptoms are experienced, it’s vital to record what symptoms occurred and their severity, how long after eating the food it occurred, and if anything else was consumed with it or in the same time frame. Between the testing period, you return to the elimination diet to avoid overlap and inaccurate results. This is usually the phase many find to be the most tedious, but doing it correctly and completely provides the most personalized diet plan. 

Phase 3: The Personalization Phase (Long-Term)

After you’ve compiled your own personal list of “no foods” and “yes foods,” now all you have to do is structure your daily eating around them. Your no foods aren’t completely off limits, but you should be careful about how much you have and how often while occasionally retesting your tolerance as it can change over time. Though the fear of having symptoms can be scary, it’s important to still eat a diverse diet within the parameters of your food list to avoid potential nutrient deficiencies.  

What You Can and Can't Eat on a Low FODMAP Diet

Again, this diet isn’t as restrictive as it seems as many low FODMAP foods are common foods you eat everyday. Just note that just because you eat a low FODMAP food doesn’t mean you are immune to symptoms, as large portions could still cause them. Nowadays, low FODMAP foods are often labeled to make the IBS diet easier to follow. 

Foods to Enjoy (Low FODMAP Options)

Proteins

• Beef
• Chicken
• Eggs
• Fish
• Pork
• Shrimp
• Turkey

Grains

• Brown rice
• Corn tortillas
• Gluten-free bread
• Oats
• Popcorn
• Quinoa
• White rice

Vegetables

• Bell peppers
• Carrots
• Cucumbers
• Eggplant
• Green beans
• Lettuce
• Potatoes
• Spinach
• Tomatoes
• Zucchini

Fruits

• Bananas
• Blueberries
• Cantaloupe
• Grapes
• Kiwi
• Oranges
• Pineapple
• Strawberries

Dairy

• Butter
• Lactose-free milk
• Hard cheeses (cheddar, parmesan)

Foods to Avoid During Elimination (High FODMAP Foods)

Grains

• Bagels
• Rye bread
• Regular pasta
• Wheat products (bread, cereal, etc.)

Vegetables

• Artichokes
• Asparagus
• Baked beans
• Black beans
• Cauliflower
• Chickpeas
• Garlic
• Kidney beans
• Lentils
• Mushrooms
• Onions
• Sugar snap peas

Fruits

• Apples
• Blackberries
• Cherries
• Mango
• Peaches
• Pears
• Plums
• Watermelon

Dairy

• Cottage cheese
• Cow’s milk products (ice cream, yogurt, soft cheeses)

Garlic and onion are the most common triggers in the US, but remember, some of these foods could be eventually introduced again.They aren’t bad foods, just those that common cause symptoms. 

Getting Started: Practical Tips for Success

It’s key to seek out a registered dietitian with a digestive health speciality as this complex process needs specialized guidance to implement successfully. There are also certain apps and other resources to help keep your food and symptom lists organized to make the low FODMAP diet less overwhelming. 

For successful meal planning and grocery shopping, ditch high FODMAP foods you already own, go to the store equipped with a list of low FODMAP foods, and keep a keen eye out on the label for hidden ingredients that may be triggers. You want to start this process when life is calm rather than busy or with upcoming plans to reduce the likelihood of having to start over. 

What to Expect: Timeline and Results

Be patient; it could take up to a month to see improvements in symptoms and those with SIBO may even feel worse before feeling better. Be sure to complete all three FODMAP diet phases for best results, but remember it’s not meant to be followed forever to maintain optimal nutrition. If symptoms do not improve, work with your doctor to explore alternative interventions. 

Working with a Registered Dietitian

Some dietitians now have certification from Monash University for low FODMAP diet coaching, but dietitians with a background in gut health and IBS can also help. Seeking a food expert is vital to navigate the diet safely and many insurance plans cover counseling if you have diagnosed digestive issues. There are dozens of specialists at Top Nutrition Coaching who can help, and getting matched to an online gut health nutritionist that is perfect for you is a comprehensive, but easy process. 

The best part is the sessions are completely virtual, so you can get the help you need without ever leaving your home. All you have to do to qualify is check your insurance coverage to get matched with a specialist today. 

Beyond the Diet: Other Factors That Matter

A low FODMAP meal plan is just one piece to the puzzle of better gut health. Paying attention to managing stress, restful sleep, and regular physical activity can also help with digestive symptoms. It is possible for people with more severe disorders to need other therapies, such as medications, in addition to diet interventions, but a holistic approach to digestive wellness is often the most effective.

Frequently Asked Questions

What is the low FODMAP diet and how does it work?

The low FODMAP diet is a temporary elimination plan designed to identify food triggers in people with digestive issues like Irritable Bowel Syndrome (IBS)

What foods can I eat on a low FODMAP diet?

A low-FODMAP diet restricts specific short-chain carbohydrates (FODMAPs) that can trigger digestive distress in sensitive individuals. 

What foods should I avoid on a low FODMAP diet?

During the initial elimination phase of a low FODMAP diet, you must avoid all foods high in fermentable carbs—fructose, lactose, fructans, galactans, and polyols.

How do I start the low FODMAP diet for beginners?

The low FODMAP diet is a three-step medical nutritional therapy specifically designed to manage symptoms of Irritable Bowel Syndrome (IBS). Because this diet is highly restrictive and nutritionally complex, it is essential to consult with a healthcare professional or a registered dietitian before starting.

Is the low FODMAP diet effective for IBS symptoms?

Yes, the low FODMAP diet is highly effective for managing Irritable Bowel Syndrome (IBS)

What are the three phases of the low FODMAP diet?

The low FODMAP diet consists of three distinct phases aimed at managing digestive symptoms like bloating and gas: Elimination, Reintroduction, and Personalization.

How long should I follow the elimination phase of the low FODMAP diet?

The elimination phase of the low FODMAP diet should be followed strictly for 2 to 6 weeks, or until your gastrointestinal symptoms improve.

Are garlic and onions allowed on a low FODMAP diet?

Garlic and onions are strictly high in fructans (a type of FODMAP) and should be completely eliminated during the initial phase of a low FODMAP diet as they are the most common triggers in those with sensitivity.

Can I follow a low FODMAP diet if I'm vegetarian or vegan?

Yes, you can absolutely follow a low FODMAP diet if you are vegetarian or vegan, though overlapping both restrictions requires careful planning to ensure you still meet your nutritional needs.

Do I need to see a dietitian to start the low FODMAP diet?

While you are not legally required to see a dietitian, major health organizations (like Johns Hopkins Medicine) and diet creators (like Monash University) strongly recommend it.

Is it safe to follow the low FODMAP diet long term?

No, the strict elimination phase of the low FODMAP diet is not safe or intended for long-term use.

Can I drink coffee on a low FODMAP diet?

Yes, plain black coffee brewed from 100% beans is low FODMAP.

What happens if the low FODMAP diet doesn't work for me?

If the low FODMAP diet doesn't relieve your symptoms, FODMAPs may not be your primary trigger.