You are currently viewing Low FODMAP Diet 101: What You Need to Know to Get Started

Low FODMAP Diet 101: What You Need to Know to Get Started

Are your digestive problems becoming more debilitating no matter what you try to do to get them under control? Your diet might be to blame, but not for the reasons you expect.

Intestinal issues like SIBO and IBS can cause chronic discomfort if you aren’t addressing their root causes. For many people, switching up their diet to reduce the prevalence of FODMAP foods is a reliable way to find relief. But what are FODMAPs, and what do you need to do to follow a low-FODMAP diet? Let’s dig into the details to find out.  

What is FODMAP?

FODMAP is an acronym, and it stands for ‘Fermentable Oligo Di-and-Monosaccharides and Polyols.’ In plain English, FODMAPs are a collection of sugar-based carbohydrates (including glucose, lactose, fructose and others) that are easily fermentable but usually not wholly absorbed when you eat them.

Many FODMAPS are naturally present in foods, while others are added during processing to enhance their texture or flavour. These compounds are common in a variety of foods, and many people are sensitive to them without realizing it. If you continuously deal with a bloated, uncomfortable stomach for no discernable reason, a FODMAP sensitivity might be to blame.

The main groups of FODMAPs include the following:

  • Oligosaccharides: Consisting of carbs like fructans (fructo-oligosaccarides and inulin) and galacto-oligosaccharides, dietary sources of oligosaccharides include wheat, rye, certain fruits and vegetables, and legumes.


  • Disaccharides: Disaccharides mainly include lactose, and familiar foods that contain them are milk, soft cheeses, and other dairy products.


  • Monosaccharides: The categorization for fructose, monosaccharides consist of fruits, agave, and honey.


  • Polyols: This group’s carbs include sorbitol, mannitol, and xylitol, which are found in certain fruits, vegetables, and sweeteners.  
Foods to avoid on fodmap

What Problems Do FODMAPS CAUSE?

woman-holding cup

To be clear, there’s nothing inherently dangerous about eating FODMAPs. These compounds are perfectly healthy for most people, but some of us are more sensitive to their effects than others. For instance, research reveals a close connection between FODMAPs and IBS, as it shows that roughly 70 percent of IBS sufferers see an improvement in their symptoms when they follow a low-FODMAPs diet.

If you’re part of the population that is most sensitive to their effects, there are two main ways that FODMAPs cause problems in your gut: by drawing fluid into your intestines, and through the fermentation of your gut bacteria.

Drawing Fluid into the Intestine: FODMAPs are “osmotically active,” which means that they work to pull  water into your intestines from the rest of your body. In extra sensitive people, this can lead to symptoms like bloating or diarrhea.

Ferments Gut Bacteria: Your body processes carbs by using enzymes to break them down into single sugars that are absorbed through your intestinal wall. However, you don’t have enzymes available to process all FODMAPS, which means that these substances can travel through the small intestine and into the large without being digested. There, the compounds are fermented by the trillions of bacteria that call your gut home, leading to gas production that can trigger bloating, stomach pain, constipation, and Irritable Bowel Syndrome.  

Do you have a feeling that your digestive symptoms are signs of a FODMAP sensitivity? The most substantial evidence is often abdominal discomfort like bloating, cramping, and or nausea after meals that contain FODMAPs ingredients, usually within 30 minutes to two hours after eating.

Fodmaps cause digestions issues

How to Follow a Low-FODMAP Diet


I don’t need to tell you that digestive discomfort isn’t ideal. The good news is that following a diet to fix your FODMAP problems is easier than you think. Best of all, a low-FODMAP diet is often only needed as a temporary measure, even though it can provide you with long-term relief.


Just as you’d expect, a low-FODMAP diet is one where you cut out as many foods with FODMAP compounds as you can so that you reduce your sensitivity to them over time. Some of the FODMAP-rich foods that you avoid include inflammatory agents like gluten, peanuts, nightshade vegetables like tomatoes and eggplant, and unfermented soy. You’ll also need to eliminate fructose-filled foods, including most fruit, honey, and other sweeteners. Citrus is okay in moderation.

Avoiding fructans requires that you stay away from any dish that contains wheat, garlic, onions, shallots, leeks, asparagus, mushrooms,squash, and green peppers. Galactans, on the other hand, are commonly found in beans and legumes.  

Dairy can be a tricky food category to deal with on a low-FODMAPs diet. Soft cheeses, yogurts, and other moderately-processed dairy products are usually best avoided, though many FODMAP sensitive people still do fine with hard cheeses like cheddar in their diet. However, it’s common to misdiagnose a dairy intolerance as a FODMAP sensitivity, so it’s a smart idea to cut out all dairy for the first 30 days of a FODMAPs diet to see if that alleviates your symptoms.   

Still confused what you can and can’t eat? A quality resource for identifying high and low FODMAP foods can be found at


Tips for Success with a Low-FODMAPs Diet

Is the process of eating for your digestive health still leaving you confused…and constipated? Low-FODMAP diets can be confusing because there’s a lot of room to customize it to your situation. As you start, keep these tips in mind for a better chance of success.  

Remember, “Low” not “No” FODMAPs: When it comes to diets, we’re all used to getting lists of foods that are entirely restricted. However, FODMAPs are beneficial in small amounts for almost everyone, as they are beneficial for gut health in the right quantities. This means you don’t want to eliminate them entirely. Instead, cut down your levels until you find a serving size that works for you.

You Don’t Have to Go Gluten-Free: While a Low-FODMAP diet is naturally lower in gluten because you don’t eat fructan-rich wheat bread, certain breads with gluten like sourdough and spelt are considered okay, despite their gluten content.


It’s Not a Long-term Lifestyle Change: While this diet will seem restrictive at first, you won’t have to follow it forever. In fact, it’s not recommended that you stay on it for more than two months at a time, and that you end the diet with specific steps to reintroduce the restricted foods back into your diet.


Ending a Low-FODMAPs Diet


The goal of a low-FODMAP’s diet is to repair your digestive system so that it can naturally renew its gut lining, destroy pathogens, and help you digest food better than before. Because the diet isn’t meant to be followed for more than two weeks to six months, you need to plan on eventually introducing these forbidden foods back into your diet.

The best time to start finishing your FODMAP diet is when you experience a significant decrease in symptoms. Plan to pick one FODMAP sub-group at a time to reintroduce into your diet so that you can adequately assess its impact on your digestive system.

Start with small samples of one food to begin with, and slowly increase its quantity until you can confirm whether or not it irritates your system. Any sign of irritation is an indicator that you should get back on an elimination diet for another week before continuing to experiment. If you come out clean, move on to the next group and keep testing your sensitivities.

Once you have an overall sense of the ways you respond to different FODMAP foods, you can organize your diet accordingly. The overall goal is to set up your diet to provide you with a range of healthy foods that don’t leave you feeling sick after you eat.

Low food map re-introduction guidelines

Concerns with a Low-FODMAPs Diet

While a low-FODMAP diet can make a positive digestive difference for many people, the eating strategy isn’t for everyone.

One concern with the diet is that it’s often restrictive to the point that you might put yourself at risk of nutritional deficiencies. For instance, high fiber foods are often also high in FODMAPs, so it’s easy for your levels to get low. To offset the risk, supplement your diet with low-FODMAP fiber sources like oranges, strawberries, green beans, spinach, oats, brown rice, and gluten-free bread.

Calcium deficiency is another common concern, so focus on keeping your levels high without dairy by drinking calcium-fortified nut and rice milks and eating oats.

In some instances, following a FODMAP-restricted diet will negatively affect your gut flora because it limits your dietary variety. For this reason, it’s smart to keep your meals as diverse as you can throughout the elimination phases so that you don’t develop further digestive problems. And, by undergoing a reintroduction phase every three months, you can ensure you consume a good variety.  


Low-FODMAP diets have been rigorously studied, and the evidence is clear that they are healthy when followed correctly. However, not everyone responds precisely the same way to the restrictions, and they tend to make a more positive difference for some people than others. For instance, some people on the diet experience symptoms like mineral deficiencies, unexplained weight loss, and rectal bleeding. If you have a history of bowel or ovarian cancer or live with a digestive disease like Celiac, a low-FODMAP diet may not be the best strategy for you.

FODMAP Diet Advice at The Dempster Clinic- Center for Functional Medicine

Eating for optimal health isn’t always a clear-cut as we wish it could be, and sometimes you need to work with an expert to ensure you stay on track. At The  Dempster Clinic- Center for Functional Medicine, I can work with you to address any dietary concerns you have, from food sensitivities to an over-reliance on caffeine, and everything in between.

I am pleased to offer a Complimentary 15-minute Discovery Session for all potential patients. This session can take place over the phone or at the clinic in person. It provides an opportunity for you to learn more about the services I offer and how they can be of benefit to you.  

Please schedule an appointment today! Your best health awaits.

Dr. John Dempster

The Dempster Clinic- Center for Functional Medicine