Intestinal Bacteria and Gut Health: Powerful Impact on Our Lives

Trillions of tiny organisms inhabit our intestines and digestive tract... They are the intestinal bacteria of our gut flora. 

It was thought that they were relatively passive guests for a long time, but now it is clear what power and influence these microbes have.

Among other things, intestinal bacteria determine our appetite, food preferences, mood, and brain health.

Additionally, and more interestingly for all the plus-size readers of this Plus Size Zeal blog, gut flora bacteria also influence our sense of hunger and satiety. 

In other words, the bacteria in our gut also significantly impact our energy regulation, fat burning, and the development of overweight and obesity!

Intestinal Bacteria And Gut Health Powerful Impact Of These Bacterial Housemates On Our Lives

Read on to learn all about intestinal bacteria, gut health, and how they influence our lives.

After that, you can take our quiz to test how much you've learned! Or, you can check out the quiz right away if you prefer.

Intestinal bacteria and gut health: Introduction

The gut microbiota, also known as intestinal flora, is the set of microorganisms (bacteria, viruses, parasites, and non-pathogenic fungi) that live in our digestive tract. 

As the above information clearly illustrates, this gut flora plays a crucial role in our health.

Good to know: Around 10,000 billion microorganisms populate our intestines and digestive tract. This is about 100 times more than the number of stars in the galaxy!

Do you often find yourself tempted to eat?

What does our appetite have to do with gut flora? Well, our microbial inhabitants in the digestive tract mainly want only one thing: lots of food. 

They can only survive and multiply well if we give them enough nutrients.

Our microbiome has many interests, some that align with our own dietary goals and others that do not. 

In any case, intestinal bacteria in our gut flora have 2 ways of achieving their goal:

  • On the one hand, they can make us crave the food they desperately need to survive. 
  • On the other hand, they can influence our moods so that we reach for the foods we want.

What role do intestinal bacteria play in terms of hunger and satiety?

American Man Who Consumes English Breakfast 3 Times A Week With Enormous Appetite

A relatively effective strategy of gut bacteria is to disrupt the regulatory systems by which our bodies regulate hunger and satiety. 

Our bodily reactions cause us to eat something when our blood sugar drops and our energy reserves dwindle. 

At the same time, our bodily systems stop our desire to eat before we overeat. 

This control of hunger and satiety occurs through a combination of receptors in the stomach, a series of hormones such as leptin and ghrelin, and other peptide messengers. 

And it is precisely these satiety and hunger messengers that many gut microbes target! 

In fact, several scientific studies have shown that many of our gut microbes can produce their own peptides, which are similar to the body's own satiety or hunger messengers.

This allows them to attach themselves to the corresponding receptors and make us believe, for example, that we are far from satiated and full.


Recommended reading: Discover a variety of informative facts and info provided in the following articles on digestive health and healthy eating:

Autonomous microsystem balancing itself

Intestinal Bacterium Escherichia Coli Provides Nutrients For Itself And Prevents Nutritional Excesses That Would Benefit Other Intestinal Bacteria

A study by French researchers demonstrated the tremendous and far-reaching influence of gut flora in this area. 

They found that gut bacteria of the species Escherichia coli significantly change their behavior when we eat a meal!

At first, they eagerly devour the nutrients we give them, and they multiply rapidly. 

But after about 20 minutes, these particular bacteria suddenly stop their production of cellular degrading agents. And they suddenly start producing specific messenger substances that our bodies usually use to indicate satiety and feeling full. 

At first glance, this seems counterproductive, doesn't it? Why would gut bacteria voluntarily cut off their supply of nutrients by signaling a feeling of satiety? 

Well, this can be explained by survival instincts and maintaining balance in the gut.

French researchers found that this may have benefits for certain types of bacteria in our gut. 

Once these bacteria have established themselves in our guts, it is best for them if the balance between species remains as stable as possible. Therefore, it is not advantageous should an unwelcome competitor suddenly gain the upper hand. 

In other words, the intestinal bacteria Escherichia coli ensures that it receives sufficient nutrients and avoids nutritional excesses that would only benefit its competitors (other gut bacteria).


Our desire for sweetness is influenced by intestinal bacteria

Our Desire For Sweet Foods Is Influenced By Gut Bacteria
Cravings For Sugar And Other Sweets Are Co Regulated By Our Intestinal System

Our desire for sweetness could also be related to the intestinal germ Escherichia coli. 

This gut bacterium produces sugar compounds in its cell wall (so-called lipopolysaccharides or LPS) that decrease our cravings for sweet foods!

Research with mice found that these sugar compounds appear to have a far-reaching influence on our desire for sweets. 

When the researchers administered the mice a strong dose of the bacterial lipopolysaccharides, their organisms responded promptly.

After about fifteen hours, the scientists detected increased levels of the satiety hormone leptin in the rodents' blood. 

And within a week, the number of taste receptors on the tongue responding to sweetness had also decreased. 

So, as a result, the mice simply had less appetite for sweet foods. 

It is unclear why the cell wall sugars of Escherichia coli have this effect. 

Escherichia Coli Bacterium Has Inhibitory Effect On Desire For Sweet Foods And Reduces Sugar Supply To Other Bacterial Strains In The Gut

One explanation here could also be competitive avoidance. In fact, this gut bacteria may require less sugar than other gut bacteria. 

Inhibiting cravings for sweet foods ensures that sugar-hungry competitors (other gut bacteria) receive less supply of sugar and thus thrive less.


Did you know that a healthy diversity in gut bacteria is crucial to be as healthy as possible? 

Find out all about diversity in the gut, gut imbalance, its consequences, and the impact of our food choices on our digestion in the articles below:

Intestinal bacteria influence our mood

The influence of gut flora may even go far beyond the purely physical... Our gut flora even manipulates our mood!

Because what many people don't know is that the bacteria in our guts produce a whole range of neurotransmitters that determine and influence our mood and behavior.

Dopamine is produced by our intestinal bacteria

Intestinal Bacterium Escherichia Coli Produces Happiness And Addiction Hormone Dopamine
An estimated 50% of the happiness and addiction hormone dopamine comes not from the brain but from our gut. 

The substance dopamine is produced there by various intestinal bacteria such as Escherichia coli, Bacillus cereus, Proteus vulgaris, and even by the pathogenic germ Staphylococcus aureus.

The concentrations of dopamine in cultures of these types of gut bacteria are 10 to 100 times higher than the concentrations of dopamine in human blood.

The neurotransmitter dopamine plays a crucial role in our reward system and in possible addictions:

  • On the one hand, dopamine elicits satisfaction and pleasure, like when we eat candy, chocolate, junk food, or salty snacks. 
  • On the other hand, a lack of dopamine causes us to crave more snacks and sugary foods.


Our gut flora influences our happiness through serotonin production

Happiness Hormone Serotonin At Work In Radiant And Happy Woman With Black Curly Glowing Hair And Red Flashy Clothing
Man In Jeans Jacket Who Feels Happy Thanks To Serotonin In The Blood Originating From Our Intestines And Digestive System
Happy Glowing Woman With Health Intestinal Bacteria Producing Plenty Of Happiness Hormone Serotonin

About 95% of the human body's serotonin (a happiness hormone) is located in the gastrointestinal tract, and the rest (5%) is in the brain. 

In other words, virtually all the serotonin in the blood comes from our gut and digestive system.

Our intestinal bacteria are thus highly involved in producing the happiness hormone serotonin.

For example, the lactic acid bacterium Bacillus infantis produces the serotonin precursor tryptophan, a substance also found in happiness-inducing chocolate. 

Good to know: Various bacteria stimulate the intestinal wall cells to produce serotonin. And serotonin is released from the gut when the enteric nerves are stimulated.

Conclusion: When our gut bacteria are absent, reduced in number, or if there is an imbalance (called dysbiosis), our serotonin levels in our body drop, and we feel less happy and a bit depressed. 

This then prompts us to eat comfort foods like chocolate or other sweets.

Healthy And Balanced Intestinal Microflora Are Critical For Feeling Happy And Not Depressed

So healthy and balanced gut flora is crucial to feeling happy and not depressed!

Gut Microbiota Affects Our Mood Without Us Even Realizing It.Png


Our digestive system can present a host of other health problems and ailments. And in many cases, plus-size people have to contend with them too! 

Discover several typical digestive problems of plus-size folks below, including matching tips and treatment techniques to minimize their impact:

Intestinal bacteria can trigger anxiety and stress

Gut Bacteria Can Trigger Anxiety And Stress Unbelievable But True
Our gut microbes can also influence our feelings of anxiety, as experiments with mice have shown.

Research showed that calm mice implanted with the gut flora of particularly anxious mice also exhibited more anxious behavior. 

Conversely, fearful, anxious animals could also be made braver via transplantation of gut flora from calm mice without anxiety symptoms. 

Certain lactic acid bacteria dampened the release of stress hormones and made their hosts braver.


Intestinal flora provokes colic to attract more nutrients

Crying Baby With Colic Provoked By Intestinal Bacteria Wanting To Get Nutrients

In more extreme cases, the bacteria of our digestive tract do not shy away from provoking pain either!

Several scientific studies show that crying children who cry a lot in the first few months and often suffer from colic show typical changes in their gut flora. 

These studies have shown that the inconsolable crying of newborns with colic is associated with changes in the gut microbiota, including:

  • Reduced numbers of Bacteroidetes
  • Decreased overall diversity of gut bacteria
  • Increased density of Proteobacteria 

It was also noted that colic in infants leads to increased administration of nutrition (milk) which can result in accelerated weight gain.

The researchers speculate that the influential power of our gut flora thus also plays a role in colic in newborns. 

A baby who cries sends a clear signal to the parents, who then pay more care and attention to the baby and will most likely also feed it more.

Put another way, colic of the intestines in newborns can be triggered by our gut bacteria to increase the administration of nutrition. 

Baby Who Has Just Cried Is Given A Bottle Of Delicious Milk And Also The Intestinal Bacteria Are Celebrating This

This gives the baby more nutrition. These nutrients then provide the gut with the bacteria they so desperately desire.


A healthy intestinal system with many different bacteria is essential to stay healthy. 

With the help of natural solutions and intelligent nutrition, you can naturally restore the balance in your gut! Learn more about it in the following specific blog posts:

Influence of the gut on our brain and nervous system

The production of hormones and signaling substances are far from the only weapons in the manipulative arsenal of our gut flora. 

Our versatile gut bacteria also influence our behavior and appetite directly through the nervous system (which provides a direct connection to our brain).

Nerve axis between the intestines and the brain

Versatile Gut Bacteria Influence Our Behavior And Appetite Through The Nervous System That Provides A Direct Connection To Our Brain

Communication between our brain and our gut happens through the vagus nerve. 

This tenth cranial nerve connects the approximately 100 million nerve cells in the digestive system to the base of our brain. Thus, it is a central communication link between our brain and the gastrointestinal system. 

Our digestive tract uses this vagus nerve to signal, among other things, when the stomach is full and we are satiated.

In addition, our internal organs also receive specific instructions from this vagus nerve.

Good to know: Studies on mice have shown that blockage of the vagus nerve leads to a loss of appetite and drastic weight loss.

By the way, the reverse is also possible! Research on rats showed that the vagus nerve can stimulate appetite and cause one to keep eating even when the stomach is already full. 

This is the case when the vagus nerve is stimulated by certain signaling substances, such as the substance noradrenaline.

Manipulated signals by the gut flora

Gut Bacteria Play Important Role When It Comes To Hunger And Satiety

Our gut bacteria have the power to affect communication between our brain and nervous system.

This is because the nerve cells of the digestive tract, which are connected to the vagus nerve, are also in contact with our intestinal system through numerous receptors on the cell surface. 

These contact points respond, for example, to signaling substances produced during digestion but also to the presence of certain bacteria and their waste products in the intestines. 

In other words, gut bacteria can disrupt vagus nerve signals (and eating behavior).

Numerous commensal and pathogenic bacteria in our intestinal system produce peptides strikingly similar to leptin, ghrelin, peptide YY, and neuropeptide Y. These are mammalian hormones that regulate the sense of satiety and hunger.

For example, certain studies show that some gut bacteria produce messenger substances that activate the vagus nerve and thus induce more desire for food.


Our gut bacteria have a significant impact on our body and brain. Among other things, they influence our appetite, leading to overweight and obesity in some cases. 

You can learn more about prebiotics and probiotics and their usefulness or uselessness in the fight against obesity. 

In addition, we also pay attention to the impact of alcohol and meat addiction on our digestive system:

A quiz about our gut flora

Take our quick quiz below and test how much you've learned from the intestinal bacteria and gut health information on this page:

True Or False Quiz On The Influence Of Gut Bacteria On Our Body And Mood

[Spoiler Alert] Open Here to View Quiz Answers

1/9 - An imbalance in the gut flora can cause mental health problems


An imbalance in the gut flora, a dysbiosis in the jargon, can play a role in certain mental disorders such as depression, autism, bipolar disorder, and so on.

One day it will probably be possible to treat these mental disorders (in part) with psychobiotics.

For your information: Psychobiotics are probiotics used to treat psychological or psychiatric problems.

2/9 - Taking antibiotics disrupts the composition of the gut microbiota


Antibiotics kill harmful bacteria but, unfortunately, also good ones. 

The longer and the more frequently antibiotics are taken, the greater the imbalance of our gut flora.

Good to know: Generally, 70% of drugs cause a temporary change in the microbiota.

Tip: Be careful giving antibiotics to toddlers as it can permanently disrupt their gut balance.

3/9 - Some foods are better than others for balancing the gut microbiota


Good foods for healthy bowels include cruciferous vegetables (broccoli, cabbage, watercress, etc.) or green vegetables (green beans, spinach, leeks, etc.). 

Foods rich in inulin (garlic, onion, shallot) also feed good gut bacteria. 

On the other hand, ultra-processed foods that are too rich in sugar or saturated fats reduce bacterial diversity, which is detrimental to our health in the short, medium, and long term!

So try to keep all forms of ultra-processed food to an absolute minimum!

4/9 - Antibiotics should be compensated with probiotic treatment


This is not necessary. 

Narrow-spectrum antibiotics, for example, are specifically suited to infections caused by a particular group of bacteria. 

The preferred use of narrow-spectrum antibiotics is because they damage less harmless bacteria when treating pathogenic bacteria.

In other words, if it's a narrow-spectrum antibiotic, you don't necessarily need to take probiotics. 

Good to know: If you are prone to antibiotic-induced diarrhea, probiotics can help and are a good idea (especially the Lactobacillus Rhamnosus or Saccharomyces Boulardii strains).

5/9 - Intestinal bacteria are a breeding ground for disease


On the contrary, gut bacteria provide a solid foundation for our immune system. The cells lining the gut act as a barrier against the spread of pathogens in the body. 

And the good bacteria in the gut fight the bad ones. 

In fact, a link has been established between the loss of diversity in the gut flora and chronic inflammatory bowel diseases such as Crohn's disease, hemorrhagic rectocolitis, etc.

6/9 - If I am sensitive to heartburn, I need to avoid prolonged reflux treatment to protect my gut flora


Proton pump inhibitors and drugs for gastroesophageal reflux and peptic ulcers alter the digestive tract's pH and disrupt the intestinal microbiota composition. 

Such drugs are safe when taken occasionally to avoid the unpleasant effects of heartburn. Still, they should be avoided in the long term.

If you are on permanent antacids, you are at increased risk of dysbiosis (an imbalance in the intestinal system).

7/9 - Everyone has the same type of intestinal bacteria


The gut flora is a unique cocktail of 200 to 300 species of bacteria, composed according to our genetic heritage, eating habits, and lifestyle.

In other words, the mix of bacteria in your gut is entirely different from that in your neighbor's intestines.

8/9 - A baby born by cesarean section is more susceptible to disruption of the gut microbiota


After a vaginal delivery, the newborn's gut microbiota is more similar to the microbiota of the mother's vagina, which is beneficial for the future balance of the gut microbiota. 

But a baby born by cesarean section is more likely to have dysbiosis (bacterial imbalances in the gut flora). 

This is because the newborn's microbiota is more similar to the microbiota of the mother's skin.

Good to know: Rubbing the newborn with vaginal fluid just after birth via cesarean section and breastfeeding can help rebalance the baby's flora.

9/9 - The intestinal flora is used to digest food


The intestinal flora completes the digestive process initiated elsewhere in the digestive tract. 

But digesting food is far from the only function of our gut flora! 

Namely, our gut bacteria also play a role in regulating our metabolism and boosting our immunity.

Did you know that our gut bacteria and digestion are closely linked to various chronic conditions and annoying ailments? 

Discover the key insights below about the impact of our microbiome on various conditions and ailments, including practical tips to make your life more enjoyable. 

Also featured are natural cleansing methods for your body and the importance of changing your diet:

Even more information about gut health