A lot of us know that our colon and intestines, both large and small, are full of bacteria and microbes. So much so in fact, that some scientists say that humans are actually more bacteria than human.

That claim isn’t that surprising when we consider that the average person has slightly more bacteria cells in his body than all other cells. The updated number isn’t as high as reported almost 10 years ago. Back then, scientists though that bacteria cells outnumbered human cells 10 to 1.

This is not the case according to a new calculation. The amount of bacteria cells in and on a “standard” human is around 40 trillion, while the human cells are around 30 trillion¹.

Although the number of bacteria cells may be up for debate even in the future, the importance of these cells have long been established to be vital not just for vibrant health, but human life.

A lot of our health can be determined by the types and ratio of bacteria we have. And as we went over, where do we have the most bacteria cells? That’s right, in our guts.

Gut Bacteria

Gut bacteria, or gut flora, are made of of a bunch of microogansims that exists along our digestive tract. You may have heard of the term microbiome. To clear up any confusion involving that, microbiome includes many different microbes like virus, fungi, etc. Gut flora is just one example.

And you may have guessed, gut bacteria is affected by our age, our environment, and more so our diet. We already know that what we eat and how we eat has a HUGE bearing on our health. The same goes for that of our gut bacteria.

The relationship between us and our gut bacteria is what’s called mutualistic, where both us and the bacteria can benefit from each other. And I think all of us can attest to that. When we eat right, we feel good, the bacteria is happy, and everything’s great. When we stress out for example, or eat a lot of junk, we feel like crap, and our gut bacteria probably isn’t doing too well either.

So what does the bacteria in our gut actually do that benefits us so much?

Many Functions Of Gut Bacteria

Stomach Bacteria
Our Best Friends

It does a lot more than just make some of us feel yucky about our insides. Our gut bacteria does everything from regulating protecting us from nasty harmful pathogens to absorbing undigested compounds from our diet. Below is a list of just a few of the many function of our gut bacteria.

  • Secrets compounds that kills or blocks entry of dangerous pathogens and bacteria
  • Supports the growth of other beneficial bacteria
  • Adapts to absorbing nutrients from the regular types of food from our diet
  • Stimulates the immune system to produce inflammation when necessary for protection
  • Also produces an anti-inflammatory response when needed
  • Regulate production of antibodies in our bodies

Those are just the functions that we know of right now. As science continues to advance, there are bound to be more functions that we’ll come to realize about these microscopic critters.

These function are all and well, and they seem to be vital for keeping us alive. But to really understand the importance of our gut bacteria, let’s consider what would happen if we don’t have enough of them, or if they’re not healthy.

Importance Of Bacteria

You feel tired all the time; lack of focus and concentration, and lethargic feeling no matter how much you sleep. You’re losing weight, but the fat around your waistline isn’t going away, which means it’s lean tissue you’re losing.

Your hormones are out of whack and you’re always moody. Your bowel movements are never consistent and it’s always a chore to do a number 2.

These are just some of the feelings we’d experience with a lack of healthy gut bacteria.

Consider again just some of the roles of these bacteria that we mentioned.

Absorption of nutrients? Lack of gut bacteria will make sure we won’t get enough, no matter how much we eat. And guess what? Your body will keep craving for certain foods when it lacks the nutrients common in those foods. This creates the vicious cycle of eating numerous calories, but not getting the nutrients out of it to satisfy your body.

One of the BIG reasons why gut bacteria is so important for fat loss.

Inflammation and anti-inflammatory responses? Not going to happen as efficiently without healthy gut bacteria. This is exemplified in people that have taken too much antibiotics over the course of their life time. Besides the fact that their bodies have grown resistant to its effects, most of the beneficial bacteria are constantly being killed off each time antibiotics are taken.

Antibiotic Pills
Don’t Pop Too Many Of These!

That’s why it’s not uncommon to see people with a history of taking antibiotics with poor immune systems. They seem to get sick very easily. And here we are with another vicious cycle: antibiotics to kill of ALL bacteria, including the good, just so our immune system is weaken and we’re more susceptible to being sick again.

And when we’re sick, guess what kind of weight we’re losing? Not just water, but lean tissue, i.e. our muscles!

If you think all that matters is the number on the scale and not the TYPE of weight you’re losing, then hurry and read this article.

According to a collaborative research done by the University of Georgia, Binghamton University, and Pennsylvania State University, the chronic consumption of high fat foods in rats shifts the population of different bacteria in their guts².

This led to a disruption in the neural pathway between the gut and the brain, which triggered inflammation in the feeding behavior regions of the brain. This caused the rats to eat more and gain weight. Wait, gut and brain neural pathway? That’s right, we’ll talk more about that in a minute. But let’s dive deeper into this study.

The researcher then injected a low dose of antibiotics, which was carefully chosen to kill of only certain bacteria, into the rats. This was aimed to reorganize the bacteria population back to its original state.

The rats’ gut to brain neural pathway returned to normal and the inflammation went away, resulting in the rats eating at the normal rate and losing the gained weight.

Anti-inflammatory foods were also used and achieved the same effect.

This study shows two very important things:

  1. Our gut bacteria has a HUGE bearing on our weight loss goals
  2. Our diet has a HUGE impact on our gut bacteria

So for many years, people have been focusing on the calories, food types, and all these other things when one of the most important aspects of our diet is its effects on our gut bacteria (calorie counting doesn’t do a thing for weight loss by the way, see why here).

One thing I do want to mention before we get into the next section, the types of fats used in the high fat diet of this study was not specified. And high fat diets have shown to be harmful for certain animals, while optimal for others.

I’m saying this because I don’t want you to rule out a high fat diet. As much as society tells us fats are bad and causes fat gain, guess what… it’s not.

I’ll get into that in another article but just withhold judgement on high fat diets. And if you’ve already slammed the hammer on that one, then just wait until my article next week :).

Link To Obesity?

This shouldn’t come as a surprise. Our guts signals our brain when it’s full so our brain can tell us to stop eating. It does this by ways of hormones like ghrelin, which is the hunger hormone.

So when our gut bacteria is out of whack, it doesn’t tell the brain that it’s full. So hunger hormones like ghrelin is

Eating Cupcake
What’s 1 Cupcake… Or 12?

never suppressed, which leads to overeating.

And as we said before, undernourishment because of a lack of healthy gut bacteria cause us to overeat too.

Right there are two of the most common causes of overeating. And it all comes down to maintaining a good population of healthy gut bacteria.

Wait, you were going to talk more about this whole gut and brain neural pathway thingy, weren’t you? Yes, I didn’t forget.

The Gut-Brain Axis: It’s All In Our Heads

A study done by Macquarie University found that sweet, fatty junk food hampers natural brain processes and inhibits memory abilities of the hippocampus of the brain³.

In other words, fast foods full of grease and sweets not only impairs our ability to remember things, but disrupts our gut from telling our brain that we are full and doesn’t need more food.

The participants of that study showed less restraint to snacking and additional eating even after significant meals compared to those who ate more vegetables and fruits as opposed to fatty junk food.

For some of us, the gut-brain axis may have been something you’ve known about. For those that are too familiar with it, it’s basically the connection between our brains, more specifically our central nervous system, and our gut.

Our gut has such a big bearing on our brains that some have even considered the gut to be a second brain.

This connection has been shown to have effects on a lot of different conditions. Some of the most common ones include:

  • Anxiety and Mood Disorder
  • Schizophrenia
  • Autism
  • Parkinson’s Disease
  • Epilepsy
  • Obsessive-Compulsive Disorder (OCD)

These are all conditions that many once thought were all in the brain. Even today, a lot of people think that the problem resides solely in the brains of those that suffer from these conditions.

A review was conducted just earlier this month on different studies involving the effects of probiotic bacteria on patients suffering from depression, autism, OCD and other central nervous system disorders. It showed that taking the probiotics improved the conditions of the patients, along with a boost in memory4.

There’s a whole lot more at stake here than just weight loss. Do we really need any more reasons to care and cherish our guts?

Now that we know how important they are to us, how do we make sure they are healthy and happy? Here are a few suggestions of what we can do. I will be writing an article very soon specifically on a type of diet that is great not only for the critters in our guts, but our mental performance, athletic performance, longevity, and overall health.

Starve Our Bacteria

Yes, you read that right. Starving our gut bacteria can do quite a bit of good for us.

In a study done by Professor Valter Longo of USC Longevity Institute at the USC Leonard Davis School of Gerontology, a diet that mimics or includes a fast activated the immune system and allowed the body to attack breast and skin cancer cells in rats5.

In another study, multiple sclerosis (MS) was slowed down when the diet was changed to a low-calorie, fasting-like style.

Another great thing they found with a diet that includes fasting and low-calorie periods is its improvement on longevity and… weight loss.

This is not to say to eat less and make sure your calories are always low (again read this if you don’t believe me). But having periods of fasting or calorie restriction can do wonders for our overall health.

The process comes down to certain enzymes being weakened when we’re in a low-calorie or fasted state. These enzymes make it difficult for our immune systems to differentiate between good, healthy cells and bad, harmful cells like cancer.

With these enzymes temporarily weakened, the immune system can tell the difference and get to work on fighting those baddies.

The same goes for the case of MS, which is when the immune system starts attacking ALL the cells in the body. Allowing the immune system to tell apart what cells should and should not be there, a fasting-like diet slows down MS by generating new cells and killing off bad ones.

Fasting actually has a whole lot more benefits than just this. So put a little bit of fasting in your routine. Not only will you save on the grocery bill a bit, you’ll feel a whole lot better too!

Keeping Them Happy

Our guts need our TLC. As much as we don’t think about the little critters in there, we need to make sure they’re healthy and in prime condition.

A major way that we’ve learned to keeping them microbes happy is having a proper diet. A big no-no we learned is routinely taking antibiotics, which kills all the bacteria, including our precious ones.

And we saw how probiotics can be used to help the gut bacteria population rebalance back to where it should be. While a fatty, sweet junk food diet is sure to sabotage that balance.

Just one more interesting fact to share with you on the importance of our gut health, the Department of Gastroenterology at Monash University conducted a study on the effects of gut-directed hypnotherapy on irritable-bowel syndrome (IBS) compared to a low FODMAP diet.

Remember the good old FODMAPs from my review on fermented cod liver oil? Yea, doctors usually recommend a diet low in those for anyone suffering from IBS. And they yield great results. That’s why it was used as a comparison.

Basically, suggestions were to patients’ subconscious mind to control and normalize gastrointestinal functions. After 6 weeks of 1 hour sessions per week, the results showed this therapy shows similar effectiveness on IBS as a low FODMAP diet. 72% of the hypnotherapy group and 71% of the diet group achieved the same margin or improvement6.

We all should do well to treat our guts with the proper foods. Our health will thank us for it!

Stay healthy,




  1. “Body’s Bacteria Don’t Outnumber Human Cells so Much after All.” Science News. N.p., n.d. Web. 24 July 2016.
  3., Mia De Graaf For. “‘Obesity Is a Brain Disease’: Western Diet of Sweet Fatty Junk Food ‘makes You Forget to Stop Eating – Even When You’re Full’ .” Mail Online. Associated Newspapers, 12 July 2016. Web. 26 July 2016.
  4. Wang H, Lee IS, Braun C, Enck P (July 2016). “Effect of probiotics on central nervous system functions in animals and humans – a systematic review”.
Like What You See? Share It!

Written by 

I've just started getting serious about health and fitness around 2014. Since then I've learned the insider info on how to optimize athletic performance and healthy living through both nutrition and proper training. The most important thing I've discovered however, is the connection between the mindset of those that excel in athletics, and those that succeed in their life pursuits. I've spent the last couple years observing and drawing these connections and similarities, finally created a platform to share with you all what I've found, and how to apply them in your own life to get similar results.

8 thoughts on “Gut Bacteria and Weight Loss

  1. Wow, the amount of information here about bacteria is astounding. The content is simple enough for a layman like me to understand. I always knew that not all bacteria are bad, but didn’t know they are that important.

    Bacteria in relation to weight loss is something many people do not consider. No wonder many find it hard to lose that belly. Is there a relation between bad breath and bacteria in our intestines?

    Thanks, and great article!

    1. Farhan,

      There is a direct correlation between halitosis and gut bacteria. A classic example is the one I mentioned where we eat lots of foods that ferments in our stomach. We know how fermentation of different foods and beverages smells. So imagine that inside the confine space of our gut! The smell has only two places to escape and our mouth is one of them.


  2. This is a lot of information on bacteria, even while studying chapters on bacteria, I have never seen so much said about the topic. Reading this reminded me of a conversation I had a few days ago with a friend who said he developed a bacterial infection that attacked his spine and doctors told him he could have been paralyzed. It was suspected that he may have picked it up while on the job taking over from other bus drivers, and sitting in their sweaty seat, may have been the culprit.

    1. Reneea,

      Sorry to hear about your friend. Anything that negatively affects the spine has the potential to be e threatening. That’s really unfortunate if that’s really how he contracted the bacteria. Hope he’s fully recovered now.


  3. It’s a funny idea to think that we might be more bacteria than we are human. But this area of research has really grown in recent years, where people are realising just how important gut bacteria is to your health. There are a lot of probiotic supplements available these days, but it’s difficult to know which one is the best one to get.

    I have heard that fasting can be good for getting rid of candida, but that tends to be quite long fasts, right? I’ve never heard of intermittent fasting being used to kill off gut bacteria, but maybe you’re right.

    1. Marcus,

      Candida can be treated with fasting, yes. Obviously the longer the fast, the more effective the treatment would be.

      Intermittent fasting doesn’t have the short term benefits like that of longer fasts, but in the longer term is great for gut bacteria health. They get a break from having to work on food all the time and has more time to work on other vital functions like fighting any harmful pathogens, producing more beneficial bacteria, etc.


  4. Hi Wing,

    I have heard of the bacteria in the guts, but I never knew how important it is to our body system.
    Now I know more of how food is being absorbed into the body and more about our immunity.
    It is really mind blowing for me reading about this bacteria and how helpful it is to the human body!
    Keep up the good work Wing

Leave a Reply

Your email address will not be published. Required fields are marked *