Diarrhoea – What’s causing it and how to feel better
This page is for people ruled by that twinge of your stomach. You know something is coming and you need to run to the toilet feeling sweaty with stomach cramps.
Loose stools and diarrhoea are a common symptom for many people with IBS and SIBO. Some people with IBS-D experience frequent bowel movements, even up to around 10 or 12 times a day. Other people will only go once or twice a day, but it’s very loose and watery each time.
👉 Diarrhoea in IBS can be triggered by poor diet, microbes in the gut, bile acid malabsorption or nervous system issues.
NB: If your diarrhoea is new or has suddenly worsened, always check in with your doctor first to rule out anything more serious.
What’s causing your loose poo?
Common causes of fast digestion can include:
Microbes in your gut
An overgrowth of bacteria in the small intestine can be a major cause of fast transit and smelly stools.
Also, people with diarrhoea may have reduced microbe diversity in the large intestine, leading to more undesirable bugs making their home in your gut.
Stress & anxiety
When you feel on edge the higher levels of stress hormones can increase the gastrocolic reflex. This is our natural way that eating triggers the need to make room for the food coming in by pushing food along the digestive tract.
Stimulants
High levels of alcohol, caffeine, tobacco or sugars can also cause frequent loose stools.
Bile acid malabsorption
BAM could account for up to a third of cases of IBS-D. If bile doesn’t get absorbed in the small intestine it can irritate the lining of the large intestine causing frequent, urgent watery diarrhoea.
How constant diarrhoea affects you
Is this you?
- You are scared to leave the house some days and long car journeys or bus trips feel out of reach due to your digestion.
- Eating feels dangerous at times, and you’ve cut out several potential trigger foods, but still don’t know which foods make things worse.
- Bloating increases throughout the day, and you feel exhausted by bedtime.
Other issues with diarrhoea include haemorrhoids, soreness from wiping, nutrient deficiency due to fast transit and dehydration.
Everyday habits that make diarrhoea worse
Getting your eating routine set up for better bowel movements can make a big difference. If you’re doing any of these you might need to make some changes:
- Fibre maxxing – Do you eat a fibre rich breakfast but then your fruit and veg tails off throughout the day? Eating all your high fibre foods in one go can cause overwhelm your capacity to break it down
- Low fibre diet – Fibre might feel it irritates your gut, but actually a low fibre diet can cause more loose stools without the gel forming properties of some fruit and veg.
- Running on empty – If you don’t take any time for yourself then your body feels like it’s under pressure all the time, which doesn’t help digestion.
- Eating too quickly – Without proper chewing your digestion has to process larger lumps of food. This can lead to more fermentation, cramps, or water to be drawn into the bowels.
Sometimes a combination of lots of small steps makes a big difference.
Poo triggered by eating
If every time you eat you feel the need to poo you may have a very strong gastrocolic reflex. This is a natural way our body makes room for more food by pushing food through the digestive tract.
This reflex can become overly sensitive, especially in times of stress or anxiety. Calming the vagus nerve linking your nervous system and your digestion is really important to manage the gut-brain connection.
An overgrowth of microbes in the small intestine (SIBO) can also cause very fast transit time, and the need to poo after each meal.
Could diarrhoea really be constipation?
When poo gets hard and stuck in your colon, it can create a blockage. As more food moves through your gut, it stretches the bowel and can make you feel bloated and sore. Sometimes, softer poo sitting behind the blockage seeps around it and comes out as diarrhoea. Even though you’ve just had a loose bowel movement, you can still be constipated.
After that kind of episode, it often feels like you haven’t properly emptied your bowels, because the hard, stuck poo is still there. This type of diarrhoea can sometimes leak out or cause a bit of incontinence, which can be embarrassing and upsetting.
What you can do next
❌ Myth: My food is going straight through me
✅ Reality: Digestion is rarely so fast that your last meal is in the toilet within minutes, or even hours. Your food might not even be the trigger of your diarrhoea.
Learn more about how digestion works so you can tackle causes of diarrhoea.
