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Updated: May 25, 2021

I got my natural blue food dye and will bake some blue muffins for the blue poop challenge. If you have not heard of this challenge yet it is Professor Tim Spector's way to measure transit time.

I usually recommend the beetroot transit time test or sweetcorn transit time test, which you can read here which works well also. But in the name of science, I have decided to do the poop challenge as it is always good to know how your gut is functioning and it is fun too!

Professor Tim Spector author of The Diet Myth and also is the head scientist behind the Predict study which is the largest nutritional study of their kind in the world. The study investigates individual nutritional responses to normal meals in order to predict personalised food responses based on individual characteristics, like the bacteria in your gut.

As part of the Zoe program, they have launched the Blue poop challenge to encourage people all over the world to get insights into their gut health. To do the challenge all you need is to take a certain amount of blue food dye baked in muffins or added to a kefir drink or other foods of your choice and time when it re-appears in your stool.

  • Your gut transit time which is a key indicator of gut health

  • It will give you an indication of the health of your gut bugs, faster transit time better health slower transit time improvement needed

We know various factors such as diet, hydration, exercise, and medications that you take also affect gut transit time just to name a few however, what many people might not be aware of is that trillions of bugs living in your gut also affect gut transit time this is called the microbiome. A healthy microbiome equals a healthy gut function. To support a healthy microbiome you need to feed them with a diverse diet. Tim Spector talks about this as if the gut is your garden the microbiome is your plants to make them nourish you need to feed them with fiber and polyphenols.

  • Eat 2 blue muffins or your choice of food for breakfast, ensure you use an adequate amount of dye as per the recipe. If you are creating your own recipe, or you can try beetroot or sweetcorn as in my post here to measure your food transit time.

  • Log your results here

  • If you have sensitivities to food colourings

  • A child with hyperactivity, whether diagnosed with ADHD or not

To take part in the blue poop challenge find my #glutenfree recipe below.

INGREDIENTS for blue muffins:

For 6 muffins Oven Temperature 170 C, gas mark 3

50 gr Rice flour

50 gr Buckwheat flour

25 gr Tapioca flour

1/2 Tablespoon gluten-free baking powder

75 gr unrefined caster sugar

Pinch of salt

30 gr dry mulberries

1/4 cup English rapeseed oil

1/2 cup plant milk (coconut or rice or almond)

1/2 tsp blue dye *see note

1/2 tsp vanilla extract


Mix all dry ingredients together

Mix all wet ingredients together

Combine both, mix together with a whisk to ensure no lumps in the mix.

Pour into muffin cases and bake for 20-25 minutes or till a skewer inserted comes out clean.

* The blue spirulina dye I used did not colour my muffins dark blue so to be extra safe I added more dye about 4 times more!

* The extra dye did not work so when my muffins came out of the oven I poured on top more blue dye. Some dyes are suited for baking and some are better for icing. Therefore I recommend you choose a blue dye recommended by the challenge organisers.

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