Q&A: Are some foods "binding"? Symptoms with milk. Poo transplants.

Welcome back to our weekly Q&A! The first question (are some foods binding?) is available to all subscribers. There are further questions behind the paywall (about dairy intolerance and allergy and about poo transplants).

If you have any questions that you would like to be answered in future weeks, please do submit them here.

We’re taking a short break from the newsletter this Friday, but will be back next Wednesday with another Q&A and the newsletter will return on Friday 21st April.

Medical Disclaimer. Although I’m a doctor, I can’t replace your registered doctor. As such, the information in this newsletter is for information purposes only. It is not intended to be a substitute for medical advice, diagnosis or treatment. Always seek the advice of your qualified healthcare provider for any medical conditions, and never disregard professional medical advice because of information you have found in this newsletter. The publisher and authors of this newsletter assume no responsibility for any adverse effects that may result from the use of the information contained herein.

Q. Hi Dr Philip. My mother always used to tell me that foods like bananas and cheese are “binding”. Is there any truth in this, please?

• Frazzled

A. Like many pieces of wisdom handed down the generations, there is a lot of truth in this. “Binding” in this context means something that firms up your bowel motion. Whether this is a good thing or a bad thing depends upon the starting point! A simple binding diet can be a very helpful thing if your starting point is diarrhoea. For example, if you’re suffering from travellers’ diarrhoea or food poisoning, a diet to help firm things up is an excellent idea! If, on the other hand, you have a tendency towards constipation (and the bloating, pain and toilet misery that goes with it) then you should avoid having too many of these food types. 

So which foods are binding? And how does it work? 

Some people recommend eating the BRAT foods diet for the short term to help control diarrhoea. BRAT stands for Bananas, Rice, Apple sauce and Toast. These foods are suggested as a simple diet that helps with binding. They are typically low in fibre and high in refined carbohydrates. This is helpful in the context of diarrhoea because the simple sugars are largely digested in the small bowel, and so little residue is left to reach the colon and trigger spasms and diarrhoea. There are nuances (of course!), such as the rice and bread should be white (as they contain lower amounts of fibre) and the bananas should be ripe. Did you know that a green banana contains about 50% more fibre than a ripe one? Or that a ripe banana is higher in sugars (and FODMAPs, which can cause bloating)?

Other foods that are classed as binding include dairy products (in particular cheese), red meat, eggs and fried foods. I wouldn’t suggest having too much of these whilst you are suffering or recovering from travellers’ diarrhoea though, as the high fat content will be challenging.

On the flip side, if you are someone who suffers from being “bunged up” then the BRAT diet should be avoided. Regular exercise, adequate hydration, good toilet practice (go when you get the urge) and a diet that is high in fibre can all assist in this situation.

The NHS has a helpful advice sheet on how to get more fibre into your diet. In the UK, the recommendations are for 30g dietary fibre intake per day. In the European Union the guideline is for at least 25g per day, to help with laxation, but a note is made that amounts higher than 25g can confer additional health benefits. Remember that fibre in the diet has many benefits other than just keeping you regular. It feeds the microbiome and reduces the risk of bowel cancer, as well as flattening the unhelpful high sugar spikes that can go with other less healthy food that we may eat alongside the fibre.