Why You Shouldn’t Optimise Gut Health!


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Gut symbiosis.

Gut health.

Lately, these words flock online fitness forums and gym floors around Australia. You’ll see countless products, programs and endorsements for an array of ways in which you can now improve your Gut Health.

But do any of these actually live up to the hype?

Is there a relationship between our Gut Health and our ability to get shredded?

Is the Gut really that important?

Let’s fill in some background so that you’re up to date with some of the basics around the gut microbiome and the microbiota. As it stands there are about 100 trillion bacteria in our body. This outnumbers our own cells by 10 to 1. To say that this amount of genetic material that resides within specific sites of the human body doesn’t matter would be rudimentary. There are clear symbiotic relationships that occur and continue to occur because of these diverse bacterial communities.

One thing that you’ll hear without a doubt is increasing gut diversity. One study of 124 individuals found between 1000 and 1150 prevalent bacterial species among all of the individuals and each individual had at least 160 such species, which seem to be largely shared. So as you can see, that is a lot of different bacterial species.

However, whenever you see claims to increase gut diversity, you’ll never see outlined which species will benefit nor will you see what is being diversified.


Is it the amount of species?

The amount within species?

Or, is it the ratio between symbiotic and non-symbiotic bacteria?

What you won’t hear is that sometimes the diversity of these microbiotas are more diverse in obese than in lean, like with Kasai et al (2015).

90% of the bacteria that has been identified fall within two main phyla (classes): Firmicutes and Bacteroidetes. The most common functions recognised for these two species types are fibre degradation, butyrate production, and symbionts/pathogens. But even with this trend of ‘common bacteria’, an observation from Rosenbaum, Knight, and Leibel (2015) needs to be kept in mind.

“The taxonomic variability in the human gut is much higher than the functional variability, as measured by a variety of methods, suggesting that many different configurations of the microbiota lead to essentially the same functional result”.

The relationship between lean and obese and the dynamics of the gut microbiome are discussed by Castaner et al (2018) in their latest review. Within the review, there seem to be a shift downwards of Bacteroidetes and increasing Firmicutes in patients that are obese or who have type 2 diabetes. Considering their review focused on any research in the last 5 years they found contrasting results when compared to earlier findings showing a stronger association with obesity having reduced bacteria diversity. Interestingly is that there are studies showing that an increase up or down of particular bacteria isn’t always correlated with reductions or increases in body fat %. In one study (Kadooka, et al (2010)), there was a reduction in abdominal, visceral and subcutaneous fat stores. But, there have been at least 3 studies that showed the use of probiotics did not increased the loss of body weight or body fat % (Sanchez et al, 2014, Remely et al, 2015, Adebola et al, 2014).

The concept around including foods within your diet with the sole intention of improving your gut diversity is also under scrutiny. At the moment, the strongest evidence seen has been implemented within animal studies showing that including foods such as probiotics or fermented foods (yoghurt, kefir, and sauerkraut) can improve metabolic markers like glucose control or carbohydrate metabolism. However, there is also evidence for the probiotic food to interfere with any of the crosstalk between the bacteria and our functions for digestion. This is why focusing only on enriching your gut bacteria is a rudimentary step and misses the forest for the trees.

There is still so much to be discovered and researchers are still discovering things daily which makes the concept of having a determinant of improving gut health laughable at best.

A general observation, which seems to be commonly reported, is the fact that not having any one particular range of bacteria is healthy, nor is it necessary to try and replicate that. The diversity and expression of these gut microbiomes can also be reflective of the dietary approach you use. 


IF your dietary approach is allowing you to be successful in your sporting, fat loss or muscle growth pursuits, then focusing on adjusting these communities may be misplaced energy. Focus efforts on eating a diverse range of food, full of fruit, vegetables, low-fat dairy and lean protein sources whilst including these probiotic/fermented foods and with only a small amount of processed food.

Focus efforts on eating a diverse range of food, full of fruit, vegetables, low-fat dairy and lean protein sources with a small amount of processed food.

Diet Smart. Not Hard.

Coach Dalton

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