The Gastrocolic Reflex: “Food Goes Right Through Me!”
Last updated: April 2023
Have you ever eaten a meal and almost right after you've eaten, you are rushing to the bathroom to have a bowel movement? You've probably used the phrase "Food goes right through me!" Many people who live with Crohn's disease or ulcerative colitis have experienced this phenomenon.
Does food go right through you?
Let's think about it: There are up to 32 feet of the intestine in the digestive tract. If you ate a slice of pizza and stood up to go to the bathroom 5 minutes later, would it really be the pizza that had reached the end of your digestive system? Did it just go right through you?1
The pizza would have had to travel through your esophagus, stomach, and 25 feet of intestine all in 5 minutes, which would be some sort of record transit time. Even though you just ate a meal and had to use the bathroom shortly after, the food did not travel all the way through your digestive system in that short amount of time.2
Why do you use the bathroom immediately after eating?
If you are eating a meal and very shortly afterward you need to use the bathroom, the cause is usually the gastrocolic reflex. The gastrocolic reflex is a reflex that stimulates contractions in the colon that can lead to using the bathroom shortly after eating a meal.3
Basically, the stomach and the colon are communicating. Once the food you have just eaten reaches the stomach, the nerves in the stomach send a message to the colon to make room because more food is coming. The colon, being the polite guy he is, starts contracting, which pushes its contents further down.4
This is why you have a bowel movement shortly after you have eaten the meal. It’s not the food that you just ate that is coming out of you. It’s waste from food that you had eaten earlier that was already further down in the digestive tract.
Overreactive gastrocolic reflex and IBD
Research has shown that some people with IBS have an overreactive gastrocolic reflex with high-pressure contractions in response to meals. Simply eating or drinking can trigger this exaggerated reflex resulting in pain, cramping, diarrhea or constipation. Several people with IBD have coexistent symptoms of IBS, so this exaggerated gastrocolic reflex can occur in people who have Crohn’s disease or ulcerative colitis.3,5
Do greasy foods make you have to go to the bathroom more often?
Greasy foods can trigger the gastrocolic reflex. Usually, large meals or foods that contain unhealthy fats can also increase the pressure of contractions of the gastrocolic reflex. This can explain why you feel like you need to use the bathroom right after you eat fried or greasy foods.6
So there you have it! The reason why you feel like you have to use the bathroom shortly after eating is because of the gastrocolic reflex. Needing to use the bathroom right after eating a meal can make a person assume that food travels extremely fast through their system – that food goes right through them.
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