Gut bacteria may be the cause of weight gain

Posted by Melissa Callaghan on


Gut bacteria may be the cause of weight gain

There are 100 trillion bacteria in our microbiome with 1000 different species and thousands upon thousands of different strains.  

The number of bacteria in our body even outweighs the number of cells we have.  The gut bacteria line your entire digestive tract and can easily live there in harmony with viruses, parasites, fungi and yeast. 

What do they do? 

The answer to this is both positive and negative.

The positive side of things is that they support your immune system, they affect your metabolism, and even your mood (gut-brain axis).

The bad news is that if the environment isn't quite right then they can also be the starting point of disease and WEIGHT GAIN.

Conditions such as:

  • auto immune diseases,
  • heart disease,
  • obesity,
  • under active thyroid
  • hormonal imbalance
  • foggy brain
  • anxiety, depression
  • type 2 diabetes,
  • insulin resistance
  • fatty liver
  • irritable bowel syndrome
  • diverticulitis
  • inflammatory bowel diseases, so many more. 

When we think of weight gain we usually associate food choices and this can be right but haven't you ever wondered why a lean person can eat so much junk food and never gain weight? and why an obese person just needs to look at a loaf of bread and they gain 10 kilos? 

It has alot to do with your gut bacteria.  Research has shown that the bacteria in a lean person is actually different to the bacteria in an obese person. 

Crazy I know but now you can understand a bit more.

The biggest impact is on nutrient extraction from food.  The gut bacteria have a lot of power and research has shown that they are some of the big decision makers when it comes to what nutrients to take out of the food you eat as well as how many calories and what to do with it.  The bacteria in an obese person chose a lot more calories that get deposited as fat than a lean person, the lean person has a lot less of those bacteria and more of the other bacteria, and on top of that the bacteria may chose to turn fibre into certain fatty acids which end up as fat deposits in your liver which leads to increased weight gain and fatty liver.

The imbalance of gut bacteria are increasing FAT DEPOSITS and causing weight gain.

For example you eat a meal (eg fast food burger) fill with bad unhealthy fats and your gut bacteria and the strains that extract more fat from food then you will gain more weight than someone who doesn't have those bacteria. 



This does not mean to take probiotics, in-actual fact a research study showed that taking certain probiotics also caused weight gain. By adding these in when the gut isn't ready you can make matters a lot worse. 

This also does not mean drinking fermented drinks such as kombucha or kefir, these too can be doing more damage if the gut hasn't been repaired and rebalanced first.


The gut needs to be repaired and microbiome rebalanced. 

There are two major families of microbes that are involved.

The Sugar Feeders &

The Fat Feeders

If you are craving sugar or carbohydrates a lot then chances are you have a higher quantity of Sugar Feeders and these are the guys that cause all of the problems. These guys even convert healthy food into compounds that increase fat storage. The frustration is you think you are eating everything right and you still gain weight. Another way of recognising that there is an imbalance is if you get bloating and cramping after food especially but not exclusively high carb foods like beans and take aways. 

Other signs that your gut is in need of a repair and rebalance?

You gain weight very easily. This can also be food choices as well.

You can't handle carbohydrates - gluten intolerant

There are also sign is if there is a problem with any of your elimination pathways. 

When there is an imbalance, the body has to use whatever elimination pathway it can.  Normally toxins would be sent to the liver and then broken down into metabolites and excreted out the bowel or kidneys. 

When there is a blockage or overload in these areas then the body has to whatever it can to eliminate.

This is usually seen in different areas such as:

Lungs - Asthma, Chronic (long term) respiratory issues, constant cough

Skin - Eczema, rashes, acne, rosacea, dark circles under eyes

Urine - Cystitis, thrush, bed wetting

Mucous membranes - sinusitis, post nasal drip, rhinitis, gingivitis, vaginitis, diarrhoea, constipation. 

Painful periods

Another sign that there is an imbalance is the constant craving of sweet foods.  The bad bacteria thrive on sugar so they are involved in causing you to crave it for their own survival. 

The major benefit of repairing and rebalancing your gut bacteria is for prevention of disease and improvement of metabolism.  Thyroid hormones are converted from inactive meaning they are doing nothing for your metabolism to active in the gut and liver and when there is an imbalance this has a huge impact on whether they get converted or not.  Also the good guys keep your immune system in check and help with prevent of bowel disease and cancer.

The good news is that all of this can change.  With a bit of repair and rebalance and eating the right foods then you can be on your way to feeling better.

As a Naturoapth I work on repairing your gut as well as guiding you through food choices to help increase your beneficial bacteria. 

Who am I?

I am a Bachelor qualified Naturopath who specialises in improving metabolic processes in the body and reducing metabolic inflammation. Major areas for improvement include gut health, thyroid, kidney, liver, weight loss and mental health. Conditions such as fatty liver, high cholesterol, high blood pressure, type II diabetes, irritable bowel conditions, depression & anxiety. I help my patients by giving them symptomatic relief while working on repairing the underlying causes of metabolic stress and waste accumulation. 

What if the solution was as simple as changing your diet and your mindset. A growing number researchers believe that it is and that you can prevent or even reverse several of our worst diseases.
As a Naturopathic Doctor and Nutritionist I wholeheartedly believe this could also be possible and that the solution isn't just another pill.  I've spent many years developing my program where I have been able to successfully help my patients reduce and even eliminate their pharma meds, lose weight (most lose 6-8 kilos in 8 weeks) and feel full of energy again and I've helped them take back their health and improve their lives and habits. I can help you too.

Melissa Callaghan ND, BHSc, BTeach
Clinical Naturopath


To book an appointment click here 




Book your appointment with Melissa to begin your individualised treatment plan specific to your signs and symptoms and medical history.

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