A beginner’s guide to the low FODMAP diet

Has your doctor has told you to try the low FODMAP diet for your IBS symptoms? But you’re confused about what to actually eat? Take a look at my guide to FODMAPs.

What is the low FODMAP diet?

The low FODMAP diet is a specially created diet for people with IBS. The low-FODMAP plan removes fermentable carbohydrates from your meals in order to reduce digestive symptoms such as bloating, excessive gas, pain, or diarrhoea.

It’s an acronym standing for:

• fermentable,
• Oligosaccharides,
• Disaccharides,
• Monosaccharides,
• And
• Polyols.

FODMAPs are types of short-chain carbohydrates found in foods which draw water into the small bowel. Then as they reach the large intestine they are fermented by our gut bacteria.

• Listen to my podcast >> Ep 17 – Demystifying the low FODMAP diet
• Listen to my podcast >> Ep 18 – Mastering FODMAP Reintroduction to your IBS diet

FODMAPs can cause problems for some people by osmotically drawing water into the bowel. This can create loose stools, bloating and cramps.

The other disruption to your digestion can be through the fermentation process which can create excess gas.

This might all sound really bad, but foods high in FODMAPs are healthy, common foods.

What are high FODMAP foods?

High FODMAP foods include things like apples, mushrooms, nectarines, cherry tomatoes, wheat, milk, onions, avocado, or artificial sweeteners.

Common foods in each FODMAP category include:

• Oligosaccharides (GOS & Fructan) – beans, nuts, onions, garlic, wheat, courgette
• Disaccharides – lactose containing dairy foods e.g. milk, yoghurt, creamy cheeses
• Monosaccharides – fructose containing foods such as red pepper, grapes, mango, asparagus
• Polyols – foods with sorbitol (cherries, apricot) and mannitol (mushrooms, celery)

Avoiding all these might sound like a nightmare. However, you only need to reduce FODMAPs to a lower level in the short term.

The elimination diet is an intervention to help you identify what kind of foods might be triggering your IBS symptoms. It’s definitely not a way of life, although I have multiple clients who start working with me after following it for years! 

How to get FODMAPPed!

The diet works in 3 phases:

1. Low FODMAP phase (removing all high FODMAPs from your diet for 2-6 weeks)
2. Reintroduction – Careful reintroduction of the higher FODMAP foods whilst you carefully monitor all your symptoms. This phase can take a long time as there is a specific way to do this.
3. Your new diet – a longer term version, eating as many of the higher FODMAP foods again. You can exclude any FODMAPs that triggered symptoms during the reintroduction phase.

It’s important to use this process as a tool to help you find your triggers, rather than a diet to follow in the long term.

Read more >> How to work on reintroduction of non-FODMAP foods after an elimination diet

Who is the low FODMAP diet for?

This elimination diet is for people with IBS. If you haven’t yet had your digestive symptoms looked at by a doctor, then you shouldn’t start on the low FODMAP diet.

This is because there are lots of digestive conditions that can present the same as IBS. These could include coeliac disease, IBD or colon cancer. Whilst the low FODMAP diet is well tested for people with IBS, it could potentially mask the symptoms, and delay diagnosis of other medical conditions.

Some people with IBS do well on a Mediterranean diet. This diet may be beneficial because it’s high in fibre which supports good gut health, and includes a wide range of legumes, wholegrains, fruits and vegetables. The Mediterranean food plan also switches processed foods for more vegetables, fibre and focussed on healthy fats like olive oil, avocados and nuts, as well as lean protein such as fish and chicken..

What are the benefits of avoiding FODMAPs?

This diet has been well researched and tested on thousands of people with IBS across the world.

Most people with irritable bowel syndrome who try removing FODMAPs feel better. In fact, 50% to 86% of patients feel better after using this dietary intervention.

Most of the research data suggests 3 out of 4 people get some benefit to their digestive symptoms. That does still leave 25% of people who don’t feel better. If this is you, it might be because your IBS isn’t caused by what you eat. 

There are other factors that can influence IBS including irregular eating patterns, mental health, exercise (too much or not enough), alcohol and caffeine intake, food intolerance or other conditions and medication. 

Does it help with weight loss?

This isn’t meant to aid weight loss. You may find at first you eat a little less as you work out the right portion sizes for the diet, but you shouldn’t be hungry, and the goal is not to cut calories.

Read more >> The low FODMAP diet and weight loss

How to use a guide to going low FODMAP

This isn’t a very easy process to follow at first, but you will soon learn which foods are high and low in FODMAPs.

1. First, familiarise yourself with the foods you can eat lots of because they don’t contain many FODMAPs (e.g.  foods like potato, oats, rice, rocket, green beans, carrots, olives, parsnip, pineapple, rhubarb). You can also eat protein foods such as meat, fish, and eggs as these don’t contain any FODMAPs.
2. Next, identify which foods are allowable in moderate portions (e.g. 1/4 avocado is ok, but 1/2 an avocado is high)
3. Make a plan for 2-3 versions of breakfast, lunch and dinner.
4. Check for FODMAP stacking – this is where you have more than one portion of a moderate FODMAP, which when added to a portion of another moderate portion makes a high FODMAP meal.

More on stacking FODMAPs

For example if you’re having a apple and avocado in the same meal:

• 2 tablespoons of apple is moderately high in sorbitol
• 2 cherries are moderately high in sorbitol

On their own these foods could be fine, but if eaten together they could add to your symptoms by tipping the amount of sorbitol into ‘high’ in one meal.

If you’re feeling a bit overwhelmed with planning meals you can download my 7 day low FODMAP meal plan for inspiration for tasty low FODMAP meals.

If you make a mistake and eat higher FODMAP foods during the restriction phase it isn’t the end of the world. Just switch back to a lower FODMAP plan and keep going.

Get support with a low FODMAP diet

Make sure you are eating a healthy, balanced diet during the restriction and reintroduction phase.

I know that this can be feel a bit daunting, and can be technically very challenging whilst avoiding so many vegetables, fruits and most dairy.

It’s important to eat enough protein, iron, calcium etc to keep up your energy whilst you’re avoiding so many FODMAPs.

Working with a registered nutrition professional is the best way to do this. It will help you be sure your diet will cover the basics whilst you’re cutting out so many foods.

Pro tip – You can also download the Monash University app for the complete list of foods high and low in FODMAPs. It covers most foods and it’s really handy to take out and about with you.

Make a plan for assessing your low FODMAP phase

If you’re going to embark on this restrictive diet you need to know exactly what you’re looking for. How will you know it’s working?

I suggest tracking your food intake and symptoms whilst in the restrictive phase, and the reintroduction phase.

Track your IBS symptoms through the low FODMAP diet

It’s important to monitor how you feel whilst undertaking the restriction phase. Think about more than just your digestion, for example: 

• Bloating – when do you bloat, how does it feel?
• Bowel movements – are there more or less trips to the toilet, how well formed are your stools?
• Excess gas – is there a change in amount or odour?
• Sleep – is it better or worse, are you waking in the night?
• Headaches
• Skin – are there any changes in skin conditions (e.g. eczema or psoriasis)?
• Mood – how do you feel?
• Appetite and nausea

These are important factors to notice when you undertake any elimination diet.

>> You can download my symptom tracker for free to help you organise your data. <<

If your IBS doesn’t get better with this way of eating, then you don’t need to carry on to the reintroduction phase. This means the digestion of FODMAPs probably aren’t causing your issues.

Don’t worry though, there are other things you can try which I’ve written about in this post on what to do when the low FODMAP diet doesn’t work.

Common issues with the low FODMAP diet

Frequently I see new clients who report they’ve tried cutting FODMAPs but it didn’t work.

This could be because FODMAPs aren’t their issue, but it often comes down to either

1. how effectively the diet has been followed, or
2. Other lifestyle issues that need to be addressed.

If you are restricting FODMAPs, but still going to bed at midnight, waking up at 5am, relying on coffee to get you through the day, then drinking a glass of wine each night to relax it’s not going to help your digestion. 

Getting your exercise, sleep and stress levels sorted are often as important as your diet. 

Can I drink alcohol on this diet? 

I normally advise my clients to stay off alcohol whilst restricting FODMAPs. This is because alcohol can unsettle your digestion. This can muddy your results of the test and reintroductions. 

The FODMAP amounts for alcohol are pretty small, so if you’re used to drinking a lot this might not seem like much!

• 1 glass beer – 375ml (small can = 330ml)
• 1 glass wine – 149ml (normal UK wine servings are 125ml or 250ml)
• spirits are classed as low FODMAP (except rum which is high)

After these amounts the drinks are considered higher for FODMAPs.

The main issue with spirits like vodka, gin or tequila is what to mix them with! Most mixers are either high FODMAP (e.g. fruit juices), or sugary fizzy drinks which can cause bloating. Ideally you will cut right down, or eliminate alcohol from your diet for the whole FODMAP-ing journey. 

What about vegetarians?

Getting the right mix of protein and key nutrients can be more challenging for people avoiding meat and fish. Vegetarians should focus on eating a good balance of eggs, low lactose yoghurt, tofu and maintaining small amounts of low-FODMAP beans and pulses. 

It’s especially tricky for people following a vegan way of eating without eggs or yoghurt but not impossible. You may need to eat a lot of tofu. Also use alternative meat products such as veggie sausages to bulk up your protein. 

• Read more >> You can read more about a healthy vegetarian diet for IBS 
• Read more >> How to increase your vegetarian protein when you’re on the low FODMAP diet

Eating a diet without many FODMAPs, and accurately following the reintroduction process is quite hard.

Especially with conflicting information online. You may find some websites say tomatoes are ok, some low FODMAP site say they aren’t! This is normally down the portion sizing.

Foods aren’t in or out, it’s all about how much you eat. 

If you’re going to try avoiding FODMAPs, make sure you are getting the most information you can from the process. You don’t want to go through all that effort and then still be unsure if these foods are a trigger or not. 

The aim is to get back to eating a wider variety of foods again.

Do you need some help changing the way you eat?

Are you worried about starting the FODMAP diet? As an IBS nutritionist, trained in the FODMAPs I can:

• guide you through process giving your clarity on what to do. You won’t lose sleep wondering what comes next
• give you recipes and meal ideas so you don’t waste more time searching for ‘low-fodmap meal ideas’ online. 
• help you identify other non-FODMAP triggers to help you reduce bloating and IBS.

Contact me to start the Gut Reset with a free phone call on info@goodnessme-nutrition.com