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The Blue Poo Challenge sees you eating food flavoured with blue food coloring to give yourself an idea of your gut transit time. Here’s why that matters and how to do the Blue Poo challenge at home.
Gut transit time is the time it takes from when you eat something to when it comes out the other end, and a healthy one can boost your health in several ways.
The Benefits of a Healthy Gut Transit Time
Let’s start with a simple one—the more balanced your gut transit system is, the less likely you are to experience diarrhea or constipation.
Not only is this better for your quality of life, but food that passes through the gut too quickly doesn’t give the gut enough time to extract the maximum amount of nutrients from the food within it.
Conversely, food that hangs around in the gut for too long can ferment, leading to uncomfortable gas and bloating and potentially causing problems like piles that develop from trying to force your body to move a stuck stool.
Looking deeper into the digestive system though, we now know that our gut bacteria are also affected by our gut transit time.
How Gut Transit Affects the Gut Bacteria
Research published in the journal Gut suggested that people with a healthy gut transit time have the most plentiful and diverse bug colonies—a factor strongly associated with good health.
These bugs feed on fibre from the food we consume. A short gut transit time means that fibre passes out of the gut too fast for the bugs to feed properly, so they are less likely to thrive. A long transit time is likely linked to generally low levels of fibre in the diet, which also starves the bacteria.
At this point, things go a bit awry. A 2016 study by researchers in Denmark found that this lack of proper nutrition actually changes bacteria’s behaviour.
Usually, when gut bacteria eat the fibre in our diet, they produce anti-inflammatory compounds that protect the gut by restoring the mucus layer that protects it from harm, ‘But, if the gut transit time is slow, the bacteria run out of carbohydrates to consume and start to feed on leftover protein,’ the study’s author Professor Henrik Munch Roager from the University of Copenhagen told Helen from The Wellness Nerd in a previous interview. ‘Instead of producing healthy bowel-restoring compounds, they now produce ones high in ammonia and sulphur that might not only damage the cells of the bowel directly but also dissolve its protective mucus layer.’ And a bowel with a thinner mucosal layer is believed to be more prone to cellular mutations that can lead to bowel cancer.
Gut Transit as a Sign of General Health
The Zoe health monitoring project also highlight more wide-ranging effects. In their work, a healthier gut transit time was also associated with lower levels of belly fat, higher levels of fibre-loving bugs, and generally better all-around health.
This may be because the diet of those with a healthy transit time included more healthy poop-promoting foods than the bugs directly affecting the body’s health.
How Long Is a Good Gut Transit Time
Faster is not better. You want to be solidly average here – and according to a study by researchers at Kings College London, on average, food takes 29 hours to go from end to end.
Don’t worry if you’re a bit outside of this; according to the researchers, anything from 14-58 hours is considered normal.
How to Test Your Gut Transit Time
One very simple test is to eat something containing sweetcorn, noting when you did so, and then keep checking your next stools for kernels. Because of its high fibre content, our body finds corn hard to digest, so a decent number of the kernels come out whole, and you’ll spot them if you examine your stool. As soon as you see them, note the time, and keep looking until they disappear. Your gut transit time is the difference between when you ate and when they appeared (and stopped).
The more fun and dramatic way is to eat muffins containing blue food colouring and note when a green/blue poop appears.
Blue Poop Muffins Recipe
Here’s the recipe that the ZOE team used. It makes 12 muffins, which are safe to eat after you have finished the challenge. You can also reduce the recipe in half to make just six.
Ingredients
245g plain, all-purpose flour
15g Baking Powder
15g granulated sugar
200g vegetable oil
230g water
1 tsp vanilla extract
1 tsp Royal Blue Food Dye
12 muffin cases
Method
Preheat the oven to 325F (170C).
Combine the flour, baking powder and sugar in a large bowl and stir.
In a jug, combine the sunflower oil, water and vanilla extract.
Make a well in the centre of the flour mixture and pour in the wet ingredients.
Add the blue food dye.
Using a whisk, mix until the wet and dry ingredients are well combined and the blue dye is distributed evenly.
Pour, or scoop, 65g of batter into a muffin case – you should end up with 12 muffins.
Bake for 24-26 minutes – or until a skewer comes out clean when inserted into the centre of the muffin.
Cool for 20-30 minutes
Eat two muffins for breakfast the next day, noting down the time. Then, see what time you pass a blue-green motion. That’s your gut transit time.
What to Do Next
If you scored within 14-58 hours, you’re all good – and the closer you are to 28 hours, the better.
If Your Gut Was Too Fast
If your gut is too fast and you regularly suffer from loose stools, bloating, gas, and cramping, go and have a chat with your doctor.
Common causes of loose stools (outside of a short-term infection like food poisoning) are problems like food intolerance, irritable bowel diseases, or another bowel condition, and it’s best to get these professionally diagnosed rather than trying to manage them yourself.
It might help to keep a food diary for a week or so before seeing the doctor in case any patterns emerge that might help them with a better diagnosis. Check out our guide on how to keep a good food diary as there’s a little more to it than you might think.
If Your Gut Was Too Slow
First, some health conditions, including an underactive thyroid and diabetes, can be linked to a slower gut transit time, so don’t beat yourself up if you’re on the slower side – chat with your doctor about what should be normal for you.
Otherwise, take a look at your diet. Do you regularly eat at least five servings of fruit and vegetables daily? Are you consuming whole grains rather than white pasta, rice, and bread? If not, then start gradually increasing the fibre level of your diet. Increasing fibre too quickly can send your gut bugs into a happy, gas-producing frenzy, leading to bloating and cramps.
Do you also drink enough water? Dehydration is also a common cause of constipation. If not, drink a glass of water as soon as you wake up to your healthy morning routine, and reach for another one if you have an energy slump mid-afternoon. You could also try our hydration challenge to keep yourself motivated.
Regular exercise also helps keep things moving, so increase your walking or other exercise.
If you still have problems, chat with your GP about what else might help.
So there you have it—the Blue Poo Challenge. Who knew blue food colouring could be so good for your health?
