Intermittent Fasting: Good or Bad for Your Gut Bacteria?

by Alejandra "Alex" Ruani — Get free science updates here.

Ever been told you need more bacterial diversity?

(You probably did hear that, from me!).

Yes, we do need a more “diverse” bacterial garden to reap all kinds of benefits – from a lower body weight to sharper senses…

But what happens if we skip a few meals?

Would these tiny helpers in our gut starve, or even die?

In this mice study, fellow scientists wondered if intermittent fasting would wipe out and exterminate entire bacterial colonies…

(A pretty scary thought for those of us who skip a few meals every now and then).

So, would our brave bacteria wither and perish if we don’t feed them?

Surprisingly, instead of the widespread chaos and destruction of entire bacterial colonies, bacterial diversity actually increased!

24h fasting increased gut bacteria diversity and lowered inflammation (Cignarella et al., 2018).

It sounds pretty counter-intuitive, but it’s true. How could this be?

Well, it might be to do with the distant history of our gut flora…

Billions of years ago, bacteria often had to survive in conditions with far less food.

Which means that when we give them too much to feed on, they gorge themselves into an early grave!

Intermittent fasting seems to flip the “growth switch” in these little guys, and then they pass on benefits to us.

(Which I think is rather kind of them, in a symbiotic way).

This cutting-edge research just adds to my excitement as I wait to see what amazing studies into this topic come up next!

If you want to find out more about how your gut microbiota could help “fix” your gut, then you can join me and my team of dedicated researchers in our 4-Step Gut Restoration Program here.



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The-Health-Sciences-Academy-Alejandra-Ruani-small1-right Alejandra "Alex" Ruani leads the research division at The Health Sciences Academy, where she and her team make sense of complex scientific literature and translate it into easy-to-understand practical concepts for their students. She is a Harvard-trained scientist and UCL doctoral researcher who specialises in cravings and appetite neurobiology, nutrition biochemistry, and nutrigenomics. Besides investigating and teaching the latest advances in health and nutrition science, Alex makes it easier to be smarter with her free Science Catch-ups.

Connect with Alex via email.

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  • minakhshi

    Reply Reply July 17, 2018


  • Irfan

    Reply Reply July 18, 2018

    Fasting, always has its advantages

  • Okechukwu Gbaruko

    Reply Reply July 20, 2018

    Nice lesson,thanks

  • Jacqueline

    Reply Reply July 24, 2018

    It’s fascinating and useful to have it confirmed. So does it follow that those who do the 5 / 2 day plan would benefit albeit to a lesser degree then ? I believe they don’t actually fast but just reduce their calorie intake. Similarly if one did a juice fast if they found it hard to fast completely, would this have a similar positive effect ?

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