The Gut Microbiome: Why Your Gut Is the Foundation of Human & Athletic Health

You’ve probably heard the phrase “trust your gut” — but what if we told you that your gut is doing more than just guiding your instincts? Inside your digestive tract live more than 100 trillion organisms — a bustling community of bacteria, viruses, fungi, and more. Collectively known as the gut microbiota, these organisms carry over 9 million genes, shaping your health in ways that go far beyond digestion (1).

 

Think of your gut microbiome like the operating system of your body. It runs in the background, quietly influencing everything from metabolism and immunity to inflammation, mood, and even body composition (2).

Just like a healthy gut builds your foundation, the right kit helps you move with confidence. Explore our High-waist leggings, slip into breathable run shorts or secure-fit biker pocket shorts, and choose the support that matches your training with High Impact Sports Bras and Medium Impact Sports Bras.

Why the Gut Microbiome Matters

• Houses over 160 bacterial species (1)
• Weighs up to 1.3 kg (3)
• More predictive of obesity than DNA (4)
• Controls metabolism, makes vitamins like folate, choline, K2 (5)
• Produces short-chain fatty acids (SCFAs) and secondary bile acids to regulate inflammation and support gut-brain signalling (6)

A diverse gut microbiome is a strong gut microbiome — and diversity is key to reducing inflammation, supporting immunity, and maintaining metabolic flexibility (7).

 

Gut Bacteria & Body Composition

 

In Peak, Dr. Marc Bubbs references a landmark study where gut bacteria from lean mice were transplanted into obese mice — and the obese mice lost weight without any diet change (4).

Today, researchers can predict obesity or leanness with up to 90% accuracy based on the microbiome (4).

 

 

 What’s Harming Our Guts?

Modern life has created the perfect storm for gut dysbiosis:

• Processed, low-fibre diets (8)
• Chronic stress and poor sleep (9)
• Overuse of antibiotics (10)
• Lack of exposure to soil or fermented foods (11)
• Overtraining and prolonged endurance exercise (12)
• Frequent alcohol consumption (13)

 

Even long-haul travel and sleep loss are known to impair blood sugar control and increase intestinal permeability (14).

 

The Gut-Brain Axis

The gut-brain axis is a two-way system of communication between the gut and brain, largely via the vagus nerve (15).

Stress, anxiety, and poor sleep can all negatively influence gut function, and vice versa (16).

The SMILES Trial

A 12-week RCT found that 32.3% of people with clinical depression achieved full remission through dietary support, compared to just 8% in the social support group. The more dietary improvement participants made, the better their mental health outcomes (17).

 

How to Build a Better Gut

1. Aim for 30+ Plant Foods per Week

The American Gut Project found those eating >30 different plants weekly had greater gut diversity than those eating <10 — regardless of whether they followed a vegan diet (18).

2. Eat Prebiotic Fibre

Prebiotics feed beneficial bacteria and produce SCFAs during fermentation (6).

Top sources: onions, garlic, bananas, lentils, oats, leeks, kiwi, apples

3. Include Both Soluble & Insoluble Fibre

• Soluble fibre: slows digestion, supports satiety, improves blood sugar control
• Insoluble fibre: adds bulk, supports motility

For every 8g/day increase in fibre, risk of type 2 diabetes drops 15%, heart disease 19%, and colon cancer 8% (19).

4. Eat Probiotic-Rich Fermented Foods

Fermented foods may improve digestion, reduce inflammation, and increase nutrient availability (20).

Top sources: yoghurt, kefir, kimchi, kombucha, miso, sauerkraut.

5. Move Your Body — Consistently

A study found that just 6 weeks of moderate-to-intense aerobic training significantly increased SCFA-producing bacteria and microbial diversity in sedentary adults. These benefits reversed after stopping (21)

6. Manage Stress & Prioritise Sleep

Stress alters gut microbiota, impairs motility, and increases inflammation (9, 15).

Sleep loss disrupts microbial diversity and increases intestinal permeability — contributing to systemic inflammation (22).

7. Limit Alcohol

Alcohol increases inflammatory endotoxins within 30 minutes of drinking (13).

Chronic consumption impairs gut lining, immunity, and microbial diversity (23).

 

Supplements That May Support Gut Health

Supplement	Potential Benefit
L-Glutamine	Fuels gut cells, may reduce permeability/inflammation (12)
Magnesium citrate	Improves bowel regularity (24)
Zinc	Supports gut barrier and microbiota balance (25)
Probiotics	Strain-specific benefits (e.g. IBS symptom relief) (26)
Peppermint oil	Reduces bloating and cramps in IBS (27)

 

 

 

Quick Takeaways

• Aim for 30+ plants/week
• Stay hydrated: 0.03L per kg bodyweight
• Eat prebiotics, probiotics, and fibre
• Exercise regularly (even walking or yoga counts)
• Sleep well and manage stress
• Limit alcohol and processed food
• Track symptoms, mood, and food patterns

 

Final Thoughts

Your gut is not just a digestion centre — it’s an immune powerhouse, a second brain, and a metabolic control hub. Small changes in diet, movement, and lifestyle can transform your gut — and your performance, mood, and overall health.

 

References

1. McDonald et al. (2018) mSystems, 3(3), e00031-18
2. Arneth BM. (2018) Postgrad Med J, 94(1114):446-452
3. Vighi et al. (2008) Clin Exp Immunol, 153 Suppl 1:3-6
4. Bubbs M. (2019) Peak: The New Science of Athletic Performance
5. Heiman & Greenway (2016) Mol Metab, 5(5):317–320
6. Blaak et al. (2020) Beneficial Microbes, 11(5):411–455
7. Chassaing et al. (2017) Curr Opin Gastroenterol, 33(6):417
8. Zheng et al. (2016) Mol Psychiatry, 21:786–796
9. Galley et al. (2014) BMC Microbiol, 14:189
10. Petersen L. (2017) [unpublished data in Peak]
11. Farzi et al. (2018) Neurotherapeutics, 15(1):5–22
12. Clark & Mach (2016) J Int Soc Sports Nutr, 13:1–10
13. Leclercq et al. (2014) Nat Commun, 5:4562
14. De Lorenzo et al. (2017) Nutrients, 9(8):869
15. Wang HX & Wang YP (2016) Chin Med J, 129(19):2373–80
16. Jiang et al. (2015) Brain Behav Immun, 48:186–94
17. Jacka et al. (2017) BMC Med, 15:23
18. Heiman & Greenway (2016) Mol Metab, 5(5):317–320
19. Reynolds et al. (2019) Lancet, 393(10170):434–445
20. Marco et al. (2017) Nutrients, 9(5):521
21. Allen et al. (2018) Med Sci Sports Exerc, 50(4):747–757
22. Benedict et al. (2012) Int J Endocrinol, 2012:301935
23. Engen et al. (2015) Alcohol Res, 37(2):223–236
24. Nielsen FH. (2010) Nutr Rev, 68(5):259–266
25. Bischoff et al. (2014) Nat Rev Gastroenterol Hepatol, 11(11):689–699
26. Hungin et al. (2013) Ther Adv Gastroenterol, 6(1):39–51
27. Ford AC et al. (2008) BMJ, 337:a2313

 

 

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