What is the difference between someone who eats until feeling full and maintains a healthy weight and someone who consumes much more food and has a resulting weight problem?
Frequently, we assume one person has a more ‘active’ metabolism than the other. However, research reveals something else may be going on, and it has to do with your microbiome and the specific strains of bacteria you do or do not have in your gut. 

Your microbiome includes trillions of different kinds of bacteria and non-bacterial organisms that live inside the gut and perform essential bodily functions. It seems these bacteria may be undermining our self-control when it comes to eating and appetite, and they can send us unwanted signals.

Certain strains of bacteria are associated with an increase in the undesirable health conditions associated with obesity and metabolic disease, such as insulin resistance, type 2 diabetes, hypertension, and elevated blood lipids.

Old Thoughts Regarding Appetite and Satiety

Only within the last 20 years (2004) has science recognized the role of the gut bacteria with appetite and satiety.

Science used to believe, as food was consumed and digested, signals from gut tissues would transmit feelings of fullness and satisfaction to specific regions of the brain responsible for regulating eating behavior, such as the hypothalamus or amygdala. This model emphasized the interplay between the nutritional and sensory aspects of food, which would activate an eating control regulatory circuit.

New Thinking About Appetite and Satiety

Recent research has shown our gut microbes are also directly participating in that regulatory circuit mentioned above by releasing bioactive molecules that influence appetite and energy balance. This circuit is actually dependent on the gut microbes assessment of their own needs! They run the show of our human body!

The "old thinking" circuits certainly exist, but gut bacteria can interact with the gut-brain axis, and produce some of the same types of chemicals that regulate satiety, such as proteins and peptide hormones. So our gut bacteria directly participate in the body’s triggering mechanisms determining both hunger and fullness.

 Additionally, the gut microbiome has been found to play a role in nutrient metabolism, affecting the efficiency of calorie extraction from food and contributing to weight regulation.

Bacterial Strains that Negatively Impact Hunger and Satiety

There’s a massive amount of microbial life in the stomach and intestines, and there are specific bacterial strains associated with negative impacts on hunger and satiety. While research in this field is ongoing, several bacterial strains have been identified as potential contributors to appetite dysregulation and increased food intake.

Here are a few examples:

Firmicutes

Increased levels of Firmicutes, a phylum of bacteria, have been associated with obesity in some studies. It has been suggested that Firmicutes may be involved in extracting more energy from the diet, potentially leading to increased hunger and weight gain.

Escherichia coli (E. coli) 

Certain strains of E. coli have been linked to increased appetite and food intake. These strains can produce certain proteins that affect gut hormone secretion and appetite regulation.

Clostridium difficile (C. difficile)

C. difficile is a bacterium that can cause gastrointestinal infections. While its impact on appetite regulation is not well understood, some studies suggest a potential association between C. difficile infection and altered appetite.

Bacterial Strains that Positively Impact Hunger and Satiety

There are bacterial strains associated with positive impacts on hunger and satiety. These strains are believed to contribute to a healthy appetite regulation and can potentially support weight management.

Here are a few examples:

Bifidobacterium 

Bifidobacterium is a genus of beneficial bacteria that is commonly found in the gut. Some studies suggest higher levels of Bifidobacterium may be associated with decreased appetite and improved satiety. These bacteria are thought to influence gut hormone secretion, promote gut barrier integrity, and help regulate energy balance.

Akkermansia muciniphila 

Akkermansia muciniphila is a mucin-degrading bacterium that resides in the gut. It has been associated with various health benefits, including appetite regulation. Research suggests higher levels of Akkermansia muciniphila may be linked to reduced appetite, improved metabolic health, and weight management.

Lactobacillus 

Lactobacillus is a genus of beneficial bacteria commonly found in fermented foods and probiotic supplements. Some studies have indicated that certain strains of Lactobacillus may influence appetite regulation. These bacteria are believed to affect gut hormone levels, modulate inflammation, and promote gut health.

Roseburia 

Roseburia is a genus of bacteria that produces butyrate, a short-chain fatty acid with potential appetite-regulating effects. Higher levels of Roseburia have been associated with improved gut barrier function and metabolic health, suggesting a potential positive impact on hunger and satiety.

Faecalibacterium prausnitzii 

Faecalibacterium prausnitzii is a butyrate-producing bacterium that has been associated with various health benefits. It is believed to have anti-inflammatory properties and may play a role in gut health and appetite regulation.

The microbiome and the weight/appetite/satiety connection is fascinating, so how do you promote a robust gut microbiome? Part 3 focuses on foods and snacks for building a powerful microbiome that works for you, not against you.

In Health and Happiness,

Kelly Harrington, MS, RDN

Registered Dietitian Nutritionist for Healthy Goods