Are Your Intestinal Bacteria Making You Fat?

The prevalence of obesity and diabetes, conditions that often go hand in hand, is skyrocketing in Western society. 

Amongst a number of other environmental, genetic and lifestyle factors, gut health has now been found to contribute to obesity. 

The human gut hosts over 1000 different species of bacteria in quantities of around 100 trillion microorganisms.

Optimally, good health relies on a ratio of around 85% “good” bacteria to 15% “bad”. However this balance is easily affected by numerous lifestyle and dietary habits. 

Common symptoms of intestinal bacterial imbalance (dysbiosis) include alternating bowel habits, constipation, diarrhoea, bloating, abdominal pain, cramping, headaches, fatigue, sugar cravings, food intolerances, allergies and thrush. 

Beneficial gut microflora, or good bacteria, are well known for their positive effects on digestion, bowel and immune health.

At present, their role in the metabolic health and regulation of inflammation – processes which are central to the development of obesity-related health disorders is less understood. 


So What Does The Research Say? 

Preliminary research has identified a few mechanisms by which gut bacteria are believed to influence weight gain and metabolic health.

  • Altered bacterial balance negatively affects fat metabolism leading to increased liver and body (adipose) fat storage.
  • Certain types of 'bad' gut bacteria promote low-grade, chronic inflammation and immune activation. Over time, this process can cause intestinal hyper-permeability (leaky gut) and a build up of toxins in the body that contributes to obesity and diabetes.
  • Increased levels of obesity-promoting bacteria such as firmicutes are believed to increase appetite, energy extraction from food and reduce insulin sensitivity. 

Interestingly, research has revealed that the composition of gut bacteria in obese individuals can differ significantly from lean individuals in the overall amount of bacteria present and ratios of certain types of bacteria. 

In addition, when people with obesity lose weight to reach a healthy weight range, their gut bacterial composition seems to revert back to a similar pattern to that of lean individuals.  

Methanobrevibacter smithii is one type of bacteria recently found to be higher in obese individuals. 


Fortunately, beneficial bacterial strains such as Bifidobacteria and Lactobacilli have been found to have positive effects on fat metabolism, converting certain fatty acids into compounds with anti-diabetic, immune modulating and anti-obesity properties.  


Common Causes of Poor Gut Health

Western Dietary Habits

A typical diet with low fibre intake and high processed fat and sugar intake inhibits the growth of our good bacteria while feeding harmful and obesity-promoting bacteria in our guts.

This may cause metabolic problems and bacterial overgrowth syndromes like thrush.


The most common medications to have a negative effect on gut bacteria are antibiotics.

A short course of antibiotics can not only knock out the bad bacteria in your system, but also destroy your good gut bacteria for weeks. 

Some species of bacteria may fail to recover for six months or longer post-antibiotic use.

Other medications that negatively affect gut health include the oral contraceptive pill, steroid medications, anti-ulcer/reflux medications and antacids, chemotherapy agents and radiation therapy.

If you are taking any of these medications, speak with your doctor regularly to assess ongoing need for their use and possible treatment alternatives with less side-effects. 

Lifestyle factors

High stress levels can negatively impact your gut bacterial balance, as can smoking cigarettes, taking recreational drugs or regularly drinking alcohol.

Pre-mixed spirits, ciders and beers are particularly bad for gut health as they are high in sugar and yeast which encourage bad bacterial overgrowth.

It is important to moderate or avoid these habits for good gut health and general wellbeing.

Reduced Exposure to Natural Bacteria During Infancy

Birth by cesarean section being formula-fed rather than breast-fed can both lead to lower gut microbial population in infants due to reduced exposure to natural bacteria from their mother. This can also cause long-term abnormalities in gut bacterial composition.


How to Nurture Your Gut and Optimise Bacterial Balance

Eat a Low-Glycemic Index (GI) Diet Based on Fresh and Unprocessed Foods

This means eating plenty of vegetables, some fruits, good-quality proteins such as free range grass-fed meats, nuts and seeds, legumes and some whole grains such as quinoa, amaranth and millet.

Fat intake should be comprised of unprocessed fats including natural fats from nuts, seeds, fish, olive oil and coconut oil. 

Include Fermented Foods in Your Diet

Fermented foods such as organic sauerkraut, kefir milk and yoghurt, kimchi, and easily made home-fermented vegetables eg. cabbage, cucumber pickles, beetroots and carrots are rich in natural probiotics and promote the growth of healthy bacteria in the gut.

Eat Prebiotic Foods and Supplement With A Good Probiotic

Prebiotics are non-digestible food fibres that provide a fuel source for good bacteria so they are able to grow and survive in the gut.

Sources to include in your diet are organic oats, berries, bananas, garlic, asparagus, green vegetables, flaxseeds, Jerusalem artichokes, legumes and chicory root (can be made as a tea).

Probiotic supplements are essential for anyone experiencing symptoms of dysbiosis and for people having trouble losing weight. 

Click here to check out Emed's best probiotic supplements. 

Avoid Allergenic Foods

Dairy and gluten containing foods are common food allergens and can cause a lot of inflammation in the digestive tract of people who cannot properly digest them.

This can lead to further immune abnormalities and metabolic disorders in the long term.

Emed offers a comprehensive food allergy test to help you identify any foods you should avoid for better health.

Keep Stress Levels Under Control

Improving your ability to cope with stress may be as easy as going for a daily walk, doing some deep breathing or making time for a hobby you enjoy.

Whatever it is, make some time for relaxation on a daily basis to improve your emotional and physical wellbeing and reduce the negative impact of stress on your health.  


Don't know where to start? Talk to your Emed Practitioner today to find out which products and nutritional strategies would best suit you.


Further Reading 



Harris, K. et al. 2012, “Is the gut microbiota a new factor contributing to obesity and its metabolic disorders?”, Journal of Obesity, Vol. 2012

Musso, G. et al. 2010, “Obesity, Diabetes, and Gut Microbiota”, Diabetes Care, Vol. 33, No. 10

Tilg, H. et al. 2011, “Gut microbiome, obesity, and metabolic dysfunction, Journal of Clinical Investigation, Vol. 121, No. 6