Gut Health: The Next Big Thing in Health & Fitness

Rudy Mawer
Written By: Rudy Mawer
December 28th, 2015
Updated: June 13th, 2020
Categories: Articles Nutrition
41.2K Reads
Gut Health: The Next Big Thing in Health & Fitness
Early research on gut health points to some surprising findings. See how improving your gut health could lower your risk for diabetes, obesity, and other diseases.

Key Facts

  • Your body is 90% bacteria and only 10% human.
  • Your body contains billions of gut microorganisms.
  • Gut health is linked to a vast array of allergies and diseases including obesity, cardiovascular disease, and certain cancers.
  • From the minute we are born our gut health is affected by environmental factors such as the food we eat, where we live and the lifestyle choices we make.
  • We are only just discovering some of the potential roles our gut health plays but further research will more than likely link our gut bacteria to most diseases and health issues.
  • The future of our gut could possibly include bacteria transplants which may improve performance, body composition, health, help with fat loss and predict or even help life threatening diseases!

With 2016 just around the corner, it's time for the next big topic in fitness. To most people’s surprise, this may well be the gut!

Although it sounds like an unusual candidate and may not be as eye-catching as some new “cure all” supplement or awesome workout routine, it is based on a lot of research and mechanisms supporting its importance.

Shortly after birth, over 1000 species of bacteria colonise in the gut. As we age, our gut health can be affected and compromised by a host of factors, including the use of antibiotics, illness, stress, aging, bad dietary habits, toxins, and lifestyle.1

The integrity of our gut is often overlooked and its importance unknown to most individuals. However, it plays a key role in allergies, inflammatory disease, body composition (fat gain/loss), digestion, nutrient absorption, and serious diseases such as obesity, diabetes and certain cancers.2

meal prepping food for improved gut health

Instant Obesity

Initial research on mice and rats highlighted the potential link of gut health to obesity and disease risk. One study in the National Academy of Science gave healthy, germ free mice a “Bacteria transplant” with unhealthy gut bacteria. They found the healthy mice increased body fat by an astonishing 57%, their triglyceride levels (fat within the blood, linked with diseases such as high cholesterol and heart disease) multiplied by 2 – 3 times the baseline amount, and insulin resistance dramatically increased.

What is more, this all occurred in only 2 weeks and with no change to their diet or lifestyle. To clarify that last sentence in case its significance is not obvious, a simple change in gut bacteria caused drastic weight gain and increased markers of disease!

A follow up study by the same author then compared a high carbohydrate and high fat diet in mice with healthy and unhealthy gut bacteria. The healthy mice gained significantly less weight; fat mass and markers of metabolic disease such as glucose (Carbohydrate) tolerance and insulin resistance were affected to a lesser degree than the mice with the bad bacteria.

Similar to the first study, this all occurred with dieting being the same between groups! The researchers highlighted several mechanisms and found that those with bad gut bacteria harvested energy into fat storage more efficiently than those with a healthy gut, which is bad news for your health and physique!

In contrast to the alteration following bad bacteria, one study provided obese mice with healthy gut bacteria. Following the feeding of a specific probiotic (healthy bacteria), L. rhamnosus PL60 caused a noticeable reduction in body fat and weight. Again, this was achieved without alteration to diet or energy balance.

If these findings transferred to humans, it could explain drastic differences in people’s ability to maintain weight or gain weight and also demonstrate the vital role of gut health on body composition, obesity and disease.

However, it is important to note that fat loss is still largely dependent on factors such as energy balance and exercise, but nonetheless the gut is clearly playing an underpinning role which can affect these variables or the overall outcome.

Gut Health in Humans

Although animal models are great for eliminating many variables in research, sometimes findings in mice do not cross over to humans. For obvious reasons, it is deemed unethical to give humans bad bacteria to make them ill and obese; however recent research has highlighted the importance of gut health in human models.

Eating for better gut health

Gut Health and Inflammatory Bowel Disease (IBD)

IBD describes chronic inflammation of part or the whole digestive tract and is common among western, economically developed countries. Research suggests it is largely caused by alterations in the gut bacteria and can lead to other serious diseases such as Crohn’s disease, arthritis and ulcerative colitis.4

Gut Health on Obesity & Diabetes

Further human research has highlighted gut health as an important factor in obesity and its related metabolic diseases. Several specific types of bacteria have been shown to play a key role, for instance, the ratio of Firmicutes to Bacteroides is correlated with bodyweight and obese individuals have been found to have a high ratio.5

Other research has found a poor gut health can cause a state of chronic inflammation, which may be linked with weight gain, obesity and disease.6 Other negative alterations in gut health such as Clostridium difficile disease can not only cause the apparent health issues, but are associated with obesity. Intervention based research is now investigating the beneficial role of pre and probiotics (which improve the healthy bacteria) in obesity and disease.7,8

As mentioned, gut bacteria is affected within minutes or even before we are born! Studies in newborn babies found that the intestinal microbial colonization (bacterial formation) is altered by early feeding (natural vs artificial), birth weight, and even the delivery method of the actual birth.9

Gut bacteria has also been shown to affect our tolerance of blood glucose (Carbohydrates), which affects an individual’s body composition, health and susceptibility to disease.10

Research into diabetes has found that changes in gut bacteria may have positive effects in both type one and type two diabetes.9 Clostridium, an important strain of bacteria, has been found to correlate with glucose levels in diabetes.9

Other bacterial strains have been linked with the key mechanisms behind diabetes. Some of them have been found to specifically improve glucose tolerance and improve insulin sensitivity, both of which are vital in fat loss, muscle growth, health and disease prevention!10, 11

Gut Health and Cancer

An unhealthy gut can also lead to gastrointestinal cancer and prostate cancer, with research showing a distinct difference in the gut bacteria for a healthy person compared to an individual with cancer.3

Interestingly, dietary admission of a specific strain of bacteria (Bifidobacterium Longum) managed to significantly suppress the incidence of colonic tumors and the degree of these tumors. Researchers suggested that this strain of bacteria may elicit a strong antitumor effect.

Preparing whole food  meals

Gut Health and Cardiovascular Disease (CVD)

The benefits continue, with research suggesting that gut health has a direct correlation on our chances of developing CVD. There are several mechanisms in which this may occur, one of which is the formation of trimethylamine from gut bacteria, which may have an anti-atherogenic effect and reduce the build-up of plaque within the arteries.

Cardiovascular dysfunction may also lead to damage within the intestinal barrier, which furthers the body’s inflammatory response.12 Certain strains of bacteria such as Escherichia coli, Klebsiella pneumonia, and Streptococcus viridians may increase the gut’s permeability or resistance, which is good.

In contrast, certain other forms of bacteria may have the opposite effect on the gut’s permeability. This may lead to increased bacteria and endotoxin translocation, Krack et al. (2005) suggested that this may be an important stimulus for inflammatory cytokine to be activated in chronic heart failure.

High cholesterol is a common and well known risk factor in CVD. Three specific strains of Lactobacillus plantarum may help with cholesterol, one study by Lam et al.  also found they reduce heart attack and improve ischemic (brain) function and recovery of heart attack patients.13

Additional Diseases

Although we are still in the infancy of research into the gut, it is likely that gut health can also affect:

  • Autism
  • HIV
  • Liver disease
  • Sleep issues
  • Inflammatory diseases

Getting Healthy Bacteria Back in your Life

Fiber rich foods improve gut health

Here are several techniques you can immediately implement to start improving your gut and reduce the bad bacteria!

  1. Eat fermented fibre foods such as pickled vegetables, kefir and fermented milk products such as cottage cheese and yogurt with ‘active cultures’.
  2. Take pre and/or probiotic supplements, ensure the probiotic includes research validated strains such as L. acidophilus, B. Lonum & B. bifidum.
  3. Eat more fruit and vegetables.
  4. Eat more total daily fibre from foods such as grains, beans, fruit and vegetables.
  5. Supplement with 2x 10g of Bob Red Mills Resistance Starch (RS) daily.
  6. Consume more resistant starch though heating and cooling certain foods such as grains.
  7. Add in a Lactate Acid Yeast wafer to 2-3 meals per day.
  8. Some research also suggests that supplemental Colostrum may improve gut permeability, especially in the presence of exercise or when taking medication such as NSAIDs. 14, 15
  9. Eat a healthy balanced diet consisting of mainly whole foods.
  10. Avoid chronic stress of any type, even excessive exercise where you struggle to recover.
  11. Avoid extremely high fat and carbohydrate diets and extremely high amounts of high fructose corn syrup, all have been shown to disrupt the gastro-intestinal barrier.16, 17


Current research is only just beginning to discover all the potential and crucial roles of gut bacteria. For example, new research has highlighted that the effect of the gut on obesity may be mediated via the regulation of the microbiota-brain-gut axis and its metabolites.

Although detailed discussion of this is beyond the scope of the current article, this means our bacteria affect every aspect of our body, including the brain! This further highlights the integrated yet complex role the gut has on health, obesity and disease.

Despite it often being ignored or overlooked, your gut should be a key focus if you are interested in your body composition and health. Apply some of the simple strategies above and see how your body composition, mood, energy and overall health improve!

  1. Gerritsen, J.; Smidt, H.; Rijkers, G.T.; de Vos, W.M. Intestinal microbiota in human health and disease: The impact of probiotics. Genes Nutr. 2011, 6, 209–240.
  2. Woodmansey, E.J. Intestinal bacteria and ageing. J. Appl. Microbiol. 2007, 102, 1178–1186.
  3. Zhang, Y. J., Li, S., Gan, R. Y., Zhou, T., Xu, D. P., & Li, H. B. (2015). Impacts of gut bacteria on human health and diseases. International journal of molecular sciences, 16(4), 7493-7519.
  4. Gravallese, E. M., & Kantrowitz, F. G. (1988). Arthritic manifestations of inflammatory bowel disease. The American journal of gastroenterology, 83(7), 703-709.
  5. Armougom, F.; Henry, M.; Vialettes, B.; Raccah, D.; Raoult, D. Monitoring bacterial community of human gut microbiota reveals an increase in Lactobacillus in obese patients and Methanogens in anorexic patients. PLoS ONE 2009, 4, e7125.
  6. Cluny, N.L.; Reimer, R.A.; Sharkey, K.A. Cannabinoid signalling regulates inflammation and energy balance: The importance of the brain-gut axis. Brain Behav. Immun. 2012, 26, 691–698.
  7. De los Reyes-Gavilan, C.G.; Delzenne, N.M.; Gonzalez, S.; Gueimonde, M.; Salazar, N. Development of functional foods to fight against obesity Opportunities for probiotics and prebiotics. Agro Food Ind. Hi Tech 2014, 25, 35–39.
  8. Kelishadi, R.; Farajian, S.; Safavi, M.; Mirlohi, M.; Hashemipour, M. A randomized triple-masked controlled trial on the effects of synbiotics on inflammation markers in overweight children. J. Pediatr. 2014, 90, 161–168.
  9. Burcelin, R.; Serino, M.; Chabo, C.; Blasco-Baque, V.; Amar, J. Gut microbiota and diabetes: From pathogenesis to therapeutic perspective. Acta Diabetol. 2011, 48, 257–273.
  10. Murri, M.; Leiva, I.; Gomez-Zumaquero, J.M.; Tinahones, F.J.; Cardona, F.; Soriguer, F.; Queipo-Ortuno, M.I. Gut microbiota in children with type 1 diabetes differs from that in healthy children: A case-control study. BMC Med. 2013, 11
  11. Amar, J.; Chabo, C.; Waget, A.; Klopp, P.; Vachoux, C.; Bermudez-Humaran, L.G.; Smirnova, N.; Berge, M.; Sulpice, T.; Lahtinen, S.; et al. Intestinal mucosal adherence and translocation of commensal bacteria at the early onset of type 2 diabetes: Molecular mechanisms and probiotic treatment. EMBO Mol. Med. 2011, 3, 559–572.
  12. Sandek, A.; Anker, S.D.; von Haehling, S. The gut and intestinal bacteria in chronic heart failure. Curr. Drug. Metab. 2009, 10, 22–28.
  13. Lam, V.; Su, J.D.; Koprowski, S.; Hsu, A.N.; Tweddell, J.S.; Rafiee, P.; Gross, G.J.; Salzman, N.H.; Baker, J.E. Intestinal microbiota determine severity of myocardial infarction in rats. FASEB J. 2012, 26, 1727–1735.
  14. Marchbank, T., Davison, G., Oakes, J. R., Ghatei, M. A., Patterson, M., Moyer, M. P., & Playford, R. J. (2011). The nutriceutical bovine colostrum truncates the increase in gut permeability caused by heavy exercise in athletes. American Journal of Physiology-Gastrointestinal and Liver Physiology, 300(3), G477-G484.
  15. Buckley, J. D., Butler, R. N., Southcott, E., & Brinkworth, G. D. (2009). Bovine colostrum supplementation during running training increases intestinal permeability. Nutrients, 1(2), 224-234.
  16. Sauter, N. S., Schulthess, F. T., Galasso, R., Castellani, L. W., & Maedler, K. (2008). The antiinflammatory cytokine interleukin-1 receptor antagonist protects from high-fat diet-induced hyperglycemia. Endocrinology, 149(5), 2208-2218.
  17. Lê, K. A., Ith, M., Kreis, R., Faeh, D., Bortolotti, M., Tran, C., ... & Tappy, L. (2009). Fructose overconsumption causes dyslipidemia and ectopic lipid deposition in healthy subjects with and without a family history of type 2 diabetes. The American journal of clinical nutrition, 89(6), 1760-1765.
  18. Leung, J.; Burke, B.; Ford, D.; Garvin, G.; Korn, C.; Sulis, C.; Bhadelia, N. Possible association between obesity and Clostridium difficile infection. Emerg. Infect. Dis. 2013, 19, 1791–1798.
  19. Cani, P.D.; Neyrinck, A.M.; Fava, F.; Knauf, C.; Burcelin, R.G.; Tuohy, K.M. Selective increases of bifidobacteria in gut microflora improve high-fat diet induced diabetes in mice through a mechanism associated with endotoxaemia. Diabetologia 2007, 50, 2374–2383.
Posted on: Sat, 02/03/2018 - 07:35

Milk,Grains and lectin beans is what kills good gut health !Very bad article.LOL

M&S Team Badge
Posted on: Mon, 02/05/2018 - 09:25

Hi Skip,

Mind providing the scientific literature you've read to back those claims? I think a lot of us might find it helpful to read if that's truly the case.

Posted on: Wed, 04/06/2016 - 09:46

Why is gut health the next big thing? I know there always needs to be the next topic in health, but I was just curios where this may have originated from if you knew. Great article!

M&S Team Badge
Posted on: Wed, 04/06/2016 - 10:16

There is a huge body of research on the gut microbiome that is continually growing and evolving which has shown connections to the immune system, energy regulation (i.e. obesity), inflammation, and a host of other factors as well.

Here's some additional reading on the subject if you're interested:

Herb Zitlow
Posted on: Mon, 12/28/2015 - 15:57

"There’s only one problem: The oft-cited 10-to-1 figure is almost certainly inaccurate. It’s a crude estimate from 1972 that established itself as a fact through repetition and generations of citations. As such, it reveals the staying power of convenient falsehoods—and how an obscure scientist who left a peculiar legacy has been cited by top researchers for decades."