Is Your Gut Bacteria Making You Gain Weight?

by Sara Vance, Nutritionist & Author of The Perfect Metabolism Plan

We are told that our weight is a simple factor of balancing our energy vs. energy out – basically if we just eat less calories (energy in) than we expend (energy out), and then we will lose weight.  Makes perfect sense, right?

Sure it would make perfect sense – if our bodies were calculators!

It’s Time to Ditch the Calorie Counting Nonsense.  

The human body just is not that simple – far from it.  Stress, hormones, our activity level, and number other factors all impact how our body is processing those calories.  And one of the key things that affects how our metabolism is working is our  microbiome.

Micro – bio – what? 

Our microbiome is bascially the collection of microorganisms that reside within and on our body.  The human body has trillions of bacterial cells – in fact, it has 10 times more bacterial cells than human cells! A large percentage – several pounds – of these bacteria live in our digestive tract – also known as “our gut.”  Some of our bacteria are “good guys,” some are the “bad guys” (pathogens), while others are “neutral”.  Our microbiome is unique to each of us – kind of like a fingerprint. But unlike a fingerprint, our microbiome is not static – it can change/shift.  So if the delicate balance gets disturbed (say by taking a round of antibiotics, or a stressful event), this can cause the pathogenic bacteria (and yeasts) to grow and take over, which research is revealing can create a cascade of issues – including weight gain.

Can’t Have Your Cake & Eat it Too?

Does it frustrate you that indulging in a piece of cake seems to cause you to gain weight, yet your friend can eat the same thing and remain her same svelte self?

Blame your firmicutes.  

Research has revealed two types of anaerobic bacteria in our digestive system that appear to affect our weight:

  • Bacteroidetes– associated with leanness, your friend that can have her cake and eat it too, probably has more bacteriodetes than you.
  • Firmicutes– associated with obesity, found in higher proportions in obese mice and humans

So what this means is – if you have more firmicutes – and you eat a piece of cake, you will extract more of the fat and calories from that cake than your friend who has more bacteriodetes.

Yep – you can see why that counting calorie thing might not be working for you…

So how do you boost the firmicutes, and reduce the bacteriodetes?  One thing you can do is to take a daily probiotic supplement.  Not only might it be useful to help you achieve a healthy weight, but it may be useful in supporting your immune system, a balanced mood, digestion, and more.  I generally look for a probiotic with at least 5 billion live and active CFUs. Lactobacillus acidophilus and bifidobacterium are 2 well studied beneficial strains, but there are a number of other useful beneficial bacterial strains.

Bacteria Can Even Save Our Life!

Clostridium difficile (C. Diff) is a bacterial infection that can cause diarrhea, and can even be life-threatening. It is becoming more common and also more difficult to treat, often recurring after several rounds of antibiotics.  A new treatment is now offering hope for these patients who are out of options – called fecal transplants (where bacteria is transferred from a healthy donor to the recipient in the form of “poop pills” – yep, you read that right – poop pills). Usually a last resort, fecal transplants can be very effective – seemingly miraculous – curing these C. Diff infections, where round after round of antibiotics failed.

But poop pills can come with unintended side effects.  According to an article in the LA Times, a woman whose antibiotic-resistant C. Diff infection was finally cured by a fecal transplant began to rapidly gain weight.  This could be partially due to all the rounds of antibiotics she took (read: Antibiotics Linked to Weight Gain – Scientific American). But because the bacteria in her poop pills had come from an overweight relative – so experts surmise that it was the bacteria in the poop pills that may have caused her to gain weight.  Read more of this story in this LA Times article.  Shifting bacteria to cause weight gain has also been demonstrated in multiple rodent studies.

Could bacteria be the weapon that we are all looking for to finally win the battle against the bulge? 

Research is beginning to point to “yes.”  Studies have even revealed that some of the weight loss that occurs with gastric bypass may be due to a shift in gut bacteria, perhaps even more so than the physiological change in the anatomy!

More research is needed and is currently underway about the impact of the microbiome on our weight and overall health.

Our gut bacteria affects our immunity (80% of our immune system resides in our gut), mental health (the gut is often referred to as the second brain), and can even raise our risk for major diseases like heart disease,diabetes, and even parkinson’s disease.  It also affects our brain and nervous system too.

The Bigger Picture – The Perfect Metabolism Plan

In addition to our microbiome,  a number of other factors affect our ability to lose weight.  The Perfect Metabolism Plan breaks it down into 10 keys to helps you get to the root of the problem – the metabolism.  Without fixing the underlying metabolism, losing the excess weight will truly be an uphill battle.  The cool thing about taking this approach is that not only can our weight come back into balance – but these 10 factors can all help to lower our disease risk too.



Article written by Nutritionist Sara Vance, author of the book The Perfect Metabolism Plan. A regular guest on San Diego morning shows, you can see many of Sara’s segments on her media page. She also offers corporate nutrition, school programs, consultations, and affordable online eCourses. Download her free 40+ page Metabolism Jumpstart eBook here.
This article is for educational purposes only. The content contained in this article is not to be construed as providing medical advice. All information provided is general and not specific to individuals. Persons with questions about the above content as how it relates to them, should contact their medical professional. Persons already taking prescription medications should consult a doctor before making any changes to their supplements or medications.
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