Low Residue: Can it do more harm than good?

A few weeks ago, I wrote a blog post on the low FODMAP diet– a diet that’s had considerable press of late but is still as poorly understood as ever. I felt that low FODMAP ( a diet that reduces certain carbohydrates) has become faddy; with everyone trying the extremely restrictive diet- without guidance or support.  It’s been proven that it can quickly alter our gut bacteria due to the limitation of foods- which got me thinking. If low FODMAP was so restrictive then what about low residue? For those of you don’t know, low residue is a popular diet prescribed to patients with inflammatory bowel disease who are flaring or have strictures and is also sometimes used for IBS-D. However, while it (like low FODMAP) is undoubtedly necessary for some patients, it too has become overused; with patients staying on it for many years and getting very little advice on staying healthy along the way.

Tell me more about the low residue diet…

The low residue diet is defined by the NHS as a diet of foods that will leave ‘a minimal amount of undigested material in the digestive tract. It stresses that the ‘low residue diet is usually followed on a temporary basis’ and may be used ‘during a flare-up in inflammatory bowel disease where the bowel walls are inflamed. It’s also used to prepare for colonoscopies and when there are obstructions and strictures.

What do you eat on a low residue diet?

The basic aim of a low residue diet is to limit the amount of fibre in the diet. The diet focuses therefore on meat,  well-cooked vegetables, and low fibre carbs. There are several different lists of foods that are ‘safe’- I note that American versions of the low residue diet (like this one) seem to allow a wider range of foods than the UK ones (like this one: sorry it’s not the clearest to follow, I couldn’t find another NHS one)

What’s the problem?

The first issue with low residue is that by perception or poor guidance, patients sometimes believe they cannot eat any vegetables at all and tend to stick to foods such as potatoes and rice. I know this first hand as I wrote a blog post entitled 7 ways to get more vegetables into your diet (even on low residue) which some people got very angry about saying that it was not possible to eat any vegetables on low residue diet. The NHS guide above states that well cooked sweet potato is fine, as is the flesh of most well-cooked seeded vegetables.

Read: 7 Ways to get more fruit+veg into your diet (even on low residue)

What’s the problem with this? Well in the short term, perhaps nothing. However, many patients are using low residue on a long term basis. You might argue if you’re reading this that’s because it’s the only diet that works. Trish from my Facebook group (Healthy Living with IBD) said: “ low residue is the only diet that keeps me normal and out of pain.and I have tried all the IBD fad diets over 45 years with Crohn’s and low residue has come out the best.”

Therefore, if you are in a position of being on this long-term then it’s really important to be aware of potential deficiencies- noticeably vitamin C, D, A, Iron and B12 that may arise from the diet.  Also be conscious that fibre helps slow down our blood sugar absorption so therefore if you are eating lots of low fibre carbs, you might have blood sugar spikes and energy dips Finally, fibre helps sweep through the colon, getting rid of ‘toxins’ (for want of a better word).

Therefore, it’s wise to consider healthier soluble fibre veggies such as sweet potatoes or consider juicing and blending- which may help the fibre become easier to digest (I’ve got lots of juicing posts to get you started or you can download my free juicing for IBD ebook). The below recipes are easily adapted to low residue but still contain veg.

   Try this recipe: Turmeric fish and sweet potato

Try this recipe: Pad Thai (peel and courgettes!)

Try This: Pumpkin Pie Smoothie

Are there any other issues?

Yes, there are several. One is that any kind of restricted long term diet can cause problems. A study by Stamford (in mice, I may add) suggested that restricting fibre long term caused an irreversible depletion in good gut bacteria.  Now, remember gut bacteria is linked to all sorts of things -not just IBD. Everything from our skin to our mental health.

Another is that it is quickly recommended by doctors but little support is offered to some patients- this seems to vary widely between individuals. Martin from Facebook explained: “ At first, I found the care pretty poor since then I have moved to Stoke on Trent and I have even been able to see the dietician who is helping me to lose excess weight and set me straight on what fruit and veg are soluble.”  Simon felt that while he was told he could eat a few vegetables if very well cooked, ” there was no recognition of too much sugar, something I’ve  learned more recently and the inflammatory effect it can generate”  Comments varied- some people found they had lots of support but others felt they were just left to go at it alone with a handout.

Fair enough but does it work?

There’s also not that much evidence that it works in the long-term and therefore this suggests it’s over relied on. A two-year trial in Italy compared long-term effects of a low residue diet, which in this case was quite restricted and defined as the elimination of whole grains, legumes and all fruits and vegetables (except for bananas and skinless potatoes). 71 patients were randomized to either continue following the low residue diet or transition to an unrestricted Italian diet. There were no differences in outcomes between the two groups when evaluating rates of flares, intestinal obstructions, need for a hospital admission and/or need for surgery. The addition of fibre into the “regular” Italian diet was tolerated well overall. The study’s authors concluded that patients should be encouraged to eat an unrestricted diet as tolerated. I would like to say that while this included patients with strictures- this is not an area I am extremely knowledgeable in  (and several of you on Twitter said the diet was vital to prevent blockages or worsening strictures) – but for patients who are without blockages and strictures, the study seems to suggest that there is no reason why they should have to stay on low residue long term.

What should I do if I am on low residue and don’t want to risk a flare up?

• Ask your doctor to check for deficiencies– it’s useful to figure out if you should be supplementing to get the vitamins and minerals you need.
• Consider introducing fruit and vegetables gradually- start with well cooked sweet potato, carrots and squash- these tend to be the most easily tolerated.
• Always talk to your doctor about dietician support.
• Checkout my healthy recipes for inspiration- most are easily adaptable for low residue.
• Keep a food diary- you can click here to download your free 7-day food diary for IBD- print it out and keep a record of your diet and introduce new foods.
• You might also want to consider a protein supplement-this can help balance sugar levels if you are eating lots of simple carbs.

I hope this blog post helped! I received lots of feedback on social media about this topic- so I’d love to hear your ideas and comments below. Am I being too harsh about low residue? Has it helped you?

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