Why is it that when we eat a meal, if we previously didn’t have to go number 2, we have to go number 2 very soon after the meal.
In: Biology
Your body isn’t trying to extract nutrients from that bit any longer, you put something more nutritious in.
Our intestines are usually not empty (there are some situations where they can be close to empty). So when we eat, the food goes into our stomach, then has to go into our intestines. Since there is already stuff there, it has to get pushed out to make room.
When your stomach is full, the pressure on the sides of your stomach causes the release of a hormone called cholecystokinin (or if you want to avoid the Greek: “gallbladder-moving-protein”). This hormone stimulates your intestines to “move things along”, as it were, and causes the release of bile from your gallbladder (hence the name) to help you digest your food.
Both bile and stomach acid are acidic, and the more acidic your intestines are, the more water tends to get added to them (which also encourages things to move along). The effect is even stronger if the foods you’ve eaten irritate your intestines somehow, like if they contain a food you’re sensitive to (say, gluten if you have celiac disease) – in this case, your body is trying to clear an irritant from your intestines, so it’ll do what it can to give you diarrhea.
It’s called the gastrocolic reflex. When your stomach gets filled, stretch receptors send a signal to your brain telling it that you’ve eaten a good meal. Your brain quickly checks in with the rest of your intestines and if there’s something towards the end of the pipe, the brain tells it to dump some ballast.
Arguably it’s rooted in an evolutionary mechanism that tries to keep you at a stable weight so in case a lion decides to run after you, you don’t have to run away with both a full stomach *and* a full bum.. best to get rid of some of the f the weight when you’re stuffing the pipe on the other end!
Latest Answers