Is it actually healthy to follow the low FODMAP diet long term?


We know that the majority of IBS sufferers will experience symptom relief when following the low FODMAP diet. Finally attaining symptom relief after many years of experiencing the pain and inconvenience of IBS flares can make IBS sufferers reluctant to re-introduce foods that have been eliminated. This is understandable. Eliminating pain, bloating, urgency, diarrhoea and constipation are all key in managing IBS, but a prolonged strict low FODMAP diet can negatively affect your health in other ways. Read on to find out why it’s important to limit the FODMAP elimination phase, as well as why it’s healthy to reintroduce FODMAPs as much as we can, and how we can achieve this balance.

healthy diet

Potential negative effects & drawbacks of a low FODMAP diet

1) FODMAP elimination reduces the numbers of ‘healthy bacteria’ in your gut which can lead to low mood

Specifically, those following the low FODMAP diet have been shown to have lower levels of the beneficial bacteria Bifidobacterium in their large intestine. These usually look after our gut by reducing inflammation, and have been linked to improved mental health. This means following the low FODMAP diet for longer than the suggested 4-8 weeks can lead to low mood. Some dietitians recommend taking a Bifidobacterium containing probiotic during the elimination phase to mitigate the risk of low mood and depression, for example Vivomix, Symprove, Multibionta or Biokult.

2) Fibre, iron and calcium intake can fall during a low FODMAP diet

It’s imperative that you seek support from a registered dietitian, so that when you eliminate high FODMAP foods you can replace these with alternatives that are equal in terms of nutritional content. Here are the main nutrients at risk:

      • Calcium. Inadequate intakes can lead to weak bones and teeth. Lactose free sources of calcium can be obtained from lactose-free dairy or fortified dairy alternatives such a nut milks, just check the nutrition label to ensure it is fortified with calcium, vitamin D, and ideally Iodine also.
      • Iron. Low iron intake can cause tiredness, lack of ability to concentrate, apathy and low mood, and hair loss. Iron can be obtained from unprocessed meat and fish as well as firm tofu, nuts and seeds, quinoa and oats. Eating both animal and plant sources of iron together can help absorption, e.g. eggs and spinach – yum!
      • Fibre. Many high FODMAP foods are high in fibre. When fibre is reduced this can lead to constipation. High fibre fruit, veg, seeds and grains that are also low FODMAP such as berries, green beans, linseeds and oats should be included in the diet, and may improve your response.

3) The low FODMAP diet is complex to follow

FODMAPs do not fit neatly into the categories of foods we are used to dealing with. The low FODMAP diet is not to be underestimated, and is another reason why talking the diet through with a dietitian can really help in terms of negotiating label reading, social plans, food shopping, meal planning for the whole family, and the cost of low FODMAP alternatives. There are a huge array of websites, books, apps and podcasts on the low FODMAP process. It’s best to check that these are written by a registered dietitian (RD) to ensure they are trustworthy. Dietitians are the only statutorily recognised nutrition professional and hold the only legally recognised graduate qualifications in nutrition and dietetics. Advice written by an ‘RD’ is therefore impartial, evidence based, and reliable. RD’s are recognised by the medical profession and therefore are in a position to liaise with your GP or gastroenterologist if this is required.

4) Support is not always easy to come by

The gold standard for successfully implementing a low FODMAP is a series of 1:1 consultations with a registered dietitian. NHS waiting lists vary, and many Trusts offer group sessions, which may mean you are in a group where patients symptoms and baseline diets vary greatly. Apps produced by Monash and KCL can help, but should be supplementary to dietitian advice, not instead of. To book in for a 1:1 consultation with myself visit my website here, or to find a local dietitian trained in FODMAP modification and IBS visit the BDA freelance dietitians directory.

How to avoid the negative effects of the FODMAP elimination phase

1) Limit the elimination phase

The suggested length of time to eliminate foods high in FODMAPs to bring about symptom relief is 4-8 weeks. Some people will experience symptom relief quicker than this. Once you have had no symptoms for 2 weeks you can move onto the reintroduction phase where you challenge high FODMAP foods one by one to assess what you can tolerate and at what portion size. If you reach 8 weeks of FODMAP elimination and have not experienced symptom relief this means FODMAP elimination will not help you, and you should slowly reintroduce high FOMDAP foods back into your diet. Other causes of symptoms should be investigated at this stage if they have not been already such as coeliac disease, inflammatory bowel disease, bile acid malabsorption, food chemical sensitivity, and depression. Referral back to your GP or gastroenterologist will enable the appropriate investigations to be carried out.

2) Repeat the reintroduction phase every 3 months

After eliminating FODMAPs the reintroduction phase reveals which FODMAPs trigger your gut symptoms and in what quantity. This can change over time as your gut health improves – you can help by nurturing your gut-brain connection with regular yoga and mindfulness, getting enough sleep (7-9 hours a night), and daily gentle movement such as walking or stretching. After 3 months have passed try challenging foods that were not initially tolerated by using half the portion size you previously tried. You might benefit from breathing exercises before challenging foods in case you have anxiety around eating foods that were previously trigger foods for you.

3) Don’t skip the Personalisation phase

Following on from the reintroduction phase comes the personalisation phase. This involves looking at the foods that are available to you that will not trigger IBS, and structuring your diet going forward. Here are some key aspects that a dietitian can help you with:

    • Modify recipes you would usually make, rather than finding completely new recipes.
    • Menu plan, and look ahead to make sure there is no ‘FODMAP stacking’ so the overall FODMAP intake is spaced throughout the day rather than lots at one meal.
    • Focus on the personalisation phase with the help of a dietitian has been shown to increase the numbers of ‘healthy bacteria’ within IBS sufferers’ guts, as well as leading to a healthier microbiome and gut environment, and therefore improved mental health.

So, in answer to my initial question ‘Is it actually healthy to follow the low FODMAP  diet long-term?’ the answer is ‘no!’. Ideally it should be a ‘low FODMAP process’ involving three key stages of FODMAP elimination, reintroduction, and personalisation. It’s all geared around maintaining as much FODMAP as your body can possibly tolerate in your diet without triggering symptoms of IBS. Here are your key take-home messages:

      • Limit the FODMAP elimination phase to the time it takes to become symptom free for 2 weeks, and follow for an absolute maximum of 8 weeks.
      • If you do not experience symptom relief after 8 weeks go back to your GP or gastroenterologist for further investigations and treatment.
      • Take Bifidobacterium containing probiotics during FODMAP elimination.
      • Your tolerance will change over time also, so never stop trying to reintroduce FODMAPs back into your diet (retry every 3 months), and your overall health, especially mental health, will be protected.
      • Get the support of a registered dietitian to maintain diet quality and variety at all times.
      • Don’t skip the personalisation phase of the low FODMAP process.

If you would like to book on for a 3 appointment bundle to go through first, second and third line advice for IBS, including support following the low FODMAP process, visit my scheduler to see my services, or book in for a free 15min phone call to discuss best how I can support you. Not only does my 3 appointment bundle include a 60min initial Zoom consultation and two 40min follow-up Zoom calls, it also covers WhatsApp support between consultations, to give you support and motivation when you need it the most.

Other blog articles you may be interested in are:

Food Intolerance or IBS? How to get a reliable test and diagnosis

5 Ways to increase Variety and Enjoyment on the Low FODMAP Diet

Article written by Helen Phadnis, Registered Dietitian and Nutrition Coach at The Bespoke Nutrition Coach

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