Low FODMAP Diet for IBS: A Beginner’s Guide
- Michaela Harron
- Mar 30
- 6 min read
Medically reviewed and written by Michaela Harron, Registered Dietitian. March 30, 2025.
Roughly 60% of people with irritable bowel syndrome (IBS) report that eating triggers their symptoms—an impact that can be both physically and emotionally exhausting. If you have IBS, chances are you’ve heard someone mention the low FODMAP diet. Maybe a doctor handed you a pamphlet, or a friend told you to “just Google it.” If that left you feeling overwhelmed and unsure where to begin, you're not alone.
I’ve been there. As a registered dietitian living with IBS, I know firsthand how confusing and frustrating the low FODMAP diet can feel at first. In fact, I attempted it not once, not twice, but three times during my nutrition degree before I finally felt like I had the right tools to do it properly.
In this blog, I’ll share some science-backed strategies, practical tips, and insights from both my personal journey and the clients I’ve supported through this process. And, of course, I’ll answer the big question we all want to know: does it actually work?
If you've spent more dinners scanning for the nearest bathroom than enjoying your meal or curled into a ball post-meal wondering what went wrong, this blog is for you. The good news? The research is incredibly promising.
In This Blog:
What is IBS?
Irritable bowel syndrome (IBS) is a disorder of the gut–brain interaction, often referred to as a functional bowel disorder. It’s characterized by recurrent abdominal pain along with changes in bowel habits, bloating, and excessive gas.
There are several subtypes of IBS, depending on the predominant stool pattern:
IBS-D (Diarrhea-predominant):
Loose stools occur at least 25% of the time
IBS-C (Constipation-predominant):
Hard or lumpy stools occur at least 25% of the time
IBS-M (Mixed type):
Both loose and hard/lumpy stools occur at least 25% of the time
These symptoms can fluctuate and significantly impact daily quality of life, which is why understanding your specific IBS subtype is an important first step in managing it effectively.
What are FODMAPs?
FODMAPs are a group of fermentable carbohydrates that aren’t fully digested or absorbed in the small intestine. When they reach the large intestine, they draw water into the gut and are fermented by gut bacteria, producing gases like hydrogen and methane as byproducts.
In people without IBS, this process is usually harmless and often goes unnoticed. But for those with IBS, the gut tends to be more sensitive—a phenomenon known as visceral hypersensitivity. This means the stretching caused by gas and water buildup can lead to uncomfortable symptoms such as:
Bloating
Abdominal pain or cramping
Excessive gas
Changes in bowel movements (diarrhea, constipation, or both)
Understanding FODMAPs and how they interact with a sensitive gut is key to managing these symptoms more effectively.
Who Is the Low FODMAP Diet Right For?
The low FODMAP diet can be a helpful tool for managing IBS, but it’s not suitable for everyone. Because it involves temporarily eliminating a wide range of foods, it’s important to approach it with care and under the guidance of a qualified healthcare professional.
This diet is not recommended for:
Individuals with a history of disordered eating
Those at risk of nutrient deficiencies
Anyone without a formal diagnosis of IBS
Before starting the low FODMAP diet, it’s essential to consult with a registered dietitian or healthcare provider to determine if it’s the right fit for your unique needs and health history.
The Low FODMAP Diet
The low FODMAP diet is a relatively new but well-researched approach to managing IBS symptoms. The first study on this diet was published in 2008, and since then, research has grown significantly. Studies consistently show that the low FODMAP diet leads to better symptom relief compared to other dietary approaches for IBS.
In fact, according to Monash University the leaders in FODMAP research up to 75% of people with IBS experience symptom improvement when following the low FODMAP diet correctly.
That said, IBS is a complex condition with many contributing factors. While this diet can be highly effective for many, it may not work for everyone. In my experience, because IBS is now understood as a gut–brain disorder, managing stress is just as important as managing food triggers. If stress is a major player in your symptoms, dietary changes alone might not be enough.
Just one more reason to finally try that meditation app or book the relaxing yoga class you’ve been eyeing!
Looking to dive deeper into digestion? Check out our top picks in The Best Gut Health Books to Health Your Gut hand-selected by dietitians to help you feel better, faster.
The 3 Stages of the Low FODMAP Diet
The low FODMAP diet is a structured, three-phase approach designed to identify and manage individual food triggers. It’s not about eliminating foods forever—it’s about creating a more personalized, symptom-friendly way of eating that works for your unique digestive system.
1. Elimination Phase
This first phase involves removing all high-FODMAP foods for a short period of time—typically 2 to 6 weeks. The goal here is to reduce IBS symptoms by giving your gut a break from foods that may be causing distress.
2. Reintroduction Phase
Once symptoms are under control, the next step is to systematically reintroduce foods—one FODMAP group at a time. There are six main categories of FODMAPs, and by testing them individually, we can pinpoint which specific types are triggering your symptoms.
3. Personalization Phase
This final and most important phase is where your diet becomes uniquely yours. Based on what you tolerated (or didn’t) during reintroduction, you’ll expand your food choices and create a long-term eating pattern that supports both symptom relief and a diverse, balanced diet.
For example, I personally tolerate fructose and sorbitol quite well, which means I can enjoy a full apple without issue. But I have a low tolerance for the GOS category of FODMAPs, so even ½ cup of chickpeas can leave me doubled over in pain. This kind of insight allows us to stop avoiding everything and instead focus on what actually matters for your body.
Why the Personalization Phase Matters
Many people stop after the elimination phase, but long-term restriction of FODMAPs can be harmful to your gut health. That’s because FODMAPs serve as prebiotic fibers, which feed the beneficial bacteria in your gut. These trillions of microbes play a crucial role in digestion, immunity, and overall health.
A more diverse, well-fed microbiome is strongly associated with better gut health and better overall health too. So, the goal is not to avoid FODMAPs forever, but to strategically reintroduce them in a way that works with your body, not against it.
Key Takeaways
IBS is a complex gut–brain disorder that can significantly impact quality of life. Understanding your subtype is key to effective management.
FODMAPs are fermentable carbohydrates that can trigger symptoms like bloating, gas, and abdominal pain in people with IBS.
The low FODMAP diet is a structured, three-phase approach (elimination, reintroduction, and personalization) designed to identify your unique food triggers.
It’s not meant to be followed long term. The goal is to expand your diet while keeping symptoms under control.
The diet can be highly effective, but it’s not right for everyone and should be done with guidance from a trained healthcare professional.
Working with a dietitian can make the process easier, more effective, and more sustainable so you can feel better and eat with more confidence.
You Don’t Have to Do This Alone
As you can see, the low FODMAP diet is more than just a list of “yes” and “no” foods. It’s a nuanced process that carries risks if done without guidance and it's absolutely something that should be done under the support of a trained medical professional.
Our dietitians at In Good Nutrition are dietitians are experts in digestive health, including the low FODMAP protocol and specialize in helping clients like you navigate each step—from elimination to full personalization. If this article resonates with your experience, we’d love to support you in building confidence with food again.
Book your consultation or learn more about our services today. You deserve to feel better in your body and we’re here to help you get there.