Low FODMAP Diet for IBS: A Beginner’s Guide

People with IBS often struggle due to their diet. It can feel like everything you eat triggers a flare-up. For some people, certain carbohydrates known as FODMAPs can trigger IBS symptoms. A low FODMAP diet can provide relief, helping people with IBS.

A low FODMAP diet is an eating plan that temporarily restricts what you eat. Foods are then reintroduced slowly to determine if they’re causing symptoms or not. It can help with common symptoms like bloating, abdominal pain, diarrhoea, or gas.

Once you’ve identified the triggers, you can return to your normal diet. It’s a smart solution for people who want to understand their dietary triggers.

What Are FODMAPs?

FODMAP stands for Fermentable Oligosaccharides, Disaccharides, Monosaccharides, and Polyols. FODMAPs are short-chain carbohydrates that are poorly absorbed in the gut. While most people don’t have any issues digesting these foods, some people can experience:

• Cramping

• Diarrhoea

• Constipation

• Stomach bloating

• Gas and flatulence

The underlying reason is that FODMAPs pull water into the bowel and trigger fermentation in the colon. Common high-FODMAP foods include onions, garlic, wheat, beans, and certain fruits.

How the Low FODMAP Diet Works

Phase 1. Elimination

The diet begins by eliminating all high-FODMAP foods. That’s harder than it sounds. You’ll need to make a list and think carefully about what you’re going to eat.

This phase lasts around 2-6 weeks, allowing your digestive system to settle.

Keep a list of symptoms, noticing what goes away. You’ll also want to make a clear list of what you’re going to reintroduce.

Phase 2. FODMAP Reintroduction

FODMAP reintroduction means you add a FODMAP group back one at a time. You’ll need to give it 1-2 weeks between each reintroduction to see if symptoms return. If they do, that’s likely a potential trigger. Remove that food from your diet and move on to the next FODMAP group.

Phase 3. Personalisation

The final goal is a varied, sustainable diet. You only want to eliminate the foods that cause symptoms. Once you know which ones are your triggers, you can return to eating everything else. Avoid unnecessary long-term restriction.

FODMAP Foods to Avoid During Elimination

If you’ve never heard of FODMAPs before, it’s hard to know where to begin. It can feel like they’re in everything. It’s best to separate them into around 6-7 categories. Here’s one way you could group them:

• Onions and garlic

• Apples and pears

• Wheat-based bread, pasta, and cereals

• Beans, lentils, and chickpeas

• Milk, soft cheeses, and some yoghurts

• Certain sweeteners like sorbitol and xylitol

• High-fructose foods such as honey and some fruit juices

Portion size also matters. Three chickpeas are unlikely to cause severe symptoms, while a spoonful of honey or a glass of fruit juice alone might cause problems. It really is individual and depends on the concentration of FODMAPs in each food.

Does the Low FODMAP Diet Work for IBS?

A low FODMAP diet really does work. In fact, it can reduce symptoms in up to 86% of people. That said, it’s challenging to perform the full elimination-reintroduction cycle. But if you’re dealing with chronic IBS, it’s worth making the effort.

However, IBS isn’t solely caused by FODMAPs. There are lots of factors, including stress, the gut-brain axis, microbiome, and food sensitivities. So even if symptoms improve, don’t expect them to disappear completely or forever.

Common Mistakes on the Low FODMAP Diet

Some of the most common mistakes people make on the low FODMAP diet include:

• Staying in the elimination phase for too long

• Cutting out more foods than necessary

• Relying on unreliable online food lists or social media advice

• Ignoring stress, sleep, and other lifestyle triggers

• Expecting diet alone to completely “cure” IBS

• Reintroducing foods too quickly or inconsistently

• Becoming overly anxious or restrictive around eating

Don’t try to wing it. It’s best to create a clear plan week by week, so you know what you’re doing. Just to reiterate, your goal is to personalise your diet, identifying problem foods, not permanently restricting what you can and can’t eat. You’re likely to find that some FODMAP foods are absolutely fine.

Should You Follow a Low FODMAP Meal Plan with Professional Support?

Yes, absolutely. You should never try to embark on the low FODMAP diet without the guidance from a registered dietician or nutritionist. This is vital to ensure you avoid nutritional imbalances or food anxiety that comes with highly restrictive dieting. Additionally, if you have a history of disordered eating then the low FODMAP diet is not advised, and other pathways should be taken with the help from a registered dietician or nutritionist.

The Functional Gut Clinic doesn’t offer dietary support. But we do offer a range of tests that can help you understand your symptoms and whether they’re really caused by IBS or something else. Alongside a FODMAP diet, it’s the best way to get to the root causes of your symptoms.

Check out the next interesting article: IBS in Women: How Periods, Hormones, Pregnancy and Menopause Affect Symptoms