Why does eating make me poo?

 
 

Why does eating make me need a poo?

Why when we have IBD can it feel like food goes straight through us?

Its down to something called the gastrocolic reflex (GR). 

 

What is the gastrocolic reflex (GR)?

why does eating make me poo_.png

The GR is a normal physiological response that controls the movement of our colon (large intestine) following a meal. This GR happens within minutes after we eat or drink.

When we eat food and our stomach stretches, it triggers the GR which increases the movement of the muscles in our colon that makes poo move through towards the exit (rectum) to allow us room to eat more. The GR is most active in the transverse colon (the bit of colon along the top) and the descending colon (the bit of colon on the left side leading down to the exit), which is the reason behind the urge to poo during or following a meal. The GR may also even be stimulated by the sight and smell of food!

The gastrocolic reflex is most active during morning time and immediately after meals which explains why these are often the times people with IBD need to go to the loo more.

 

The Gastrocolic Reflex and IBD

When we have active inflammation, particularly in the parts of the colon mentioned above (UC or Crohn’s Colitis) where GR is most active, it may cause pain and make us need the loo more urgently when we start eating or soon after because it makes our bowels move more.

Often clients I work with mistake this GR for intolerance to the food they are eating but as you can see it’s a natural response to food entering our stomach which causes our bowels to move.  

Research shows that some people with IBS (irritable bowel syndrome) have a stronger colonic response to the GR causing more contractions of the muscles and an even stronger urge to poo after eating. They may also experience symptoms like bloating, flatulence, pain, and anal pain. Many people with Crohn’s and colitis also have symptoms of IBS particularly in remission which is why some people with IBD may experience this. There is also some evidence that changes in the gut microbiome (all the trillions of microbes that live within our intestines), which is common in people with IBD and IBS, may impact the movement of our intestines too.   

 

Using the GR to our advantage with IBD

As a result of the increased activity of the GR in the morning and after meals, I know some people with Crohn’s or Colitis avoid eating in the mornings, especially if you’re running out of the door.

Whilst this might help reduce to need to go to the loo, it means starting the day with an empty stomach and without the energy and nutrients our body’s need to function properly and stay healthy.  

It can be helpful to allow plenty of time in the mornings to eat and then go to the loo a few times before leaving the house. So rather than avoiding and being afraid of the GR we can plan around it to make life easier. I also find it helpful to make sure I am not too far from a loo when I do eat so I can pop to the bathroom when I need to without worrying. When I am out and about this does take a bit more planning but it helps me avoid anxiety around needing the loo.

 

References

Malone JC, Thavamani A. Physiology, Gastrocolic Reflex. [Updated 2020 Jul 10]. In: StatPearls [Internet]. Treasure Island (FL): StatPearls Publishing; 2021 Jan-. Available from: https://www.ncbi.nlm.nih.gov/books/NBK549888/

Clemmie Macpherson