Your gut bacteria contribute to your health well beyond your intestinal tract. Further upon playing an essential role in digestion, your microflora (gut bacteria) produce chemicals that move into your circulation, affecting a number of metabolic processes; these may include your appetite, cravings and mood.
So how might your gut bacteria affect your weight loss or gain?
Calorie-harvesting gut bacteria
Your gut microflora is made of various types of bacteria, with estimates at more than 300 different species living within the average intestinal tract. When we eat food, not all of it is digested. Some of it, for example fibre, moves through your intestine and ends up in your large colon.
Majority of your gut bacteria live in your large colon (aka large intestine).
These bacteria living in your large intestine grab a hold of some of those undigested food parts and use them for fuel, releasing a number of by-products. Interestingly, there are some particular bacterial species that are superior at harvesting extra calories from undigested foods, which in turn contributes to some of us absorbing more calories from our foods than others.
If we have higher numbers of these particular bacteria, this may influence weight gain through extra calorie harvesting!
Research has found that ingestion of a high fat diet is associated with a chronic (long term) elevation of plasma lipopolysaccharide (LPS) levels; a breakdown product of certain gut bacteria. Nerves in the gut mucosa (lining) are positioned to send messages from the gut to the brain to regulate food intake. These nerves are responsive to LPS levels.
A recent study found that chronically elevated LPS levels can reduce leptin signalling; a hormone that suppresses our appetite after a meal.
Elevated LPS levels, produced by certain gut bacteria, can therefore result in overconsumption of calories via not letting us get that “full” feeling, and in turn may influence weight gain.
High-fat & high-sugar food cravings
Another study suggested that particular gut bacteria may influence our decisions and cravings, via releasing molecules that send signals throughout our bodies.
These signals can influence our immune system, endocrine (hormone) system and nervous system, and potentially cause us to make particular food decisions.
For example, research on chocolate cravings has found that, even when eating identical diets, people who “crave chocolate” have different microbial (bacterial) breakdown products in their urine compared to people who are “not-interested in chocolate”.
Once again, gut bacteria possibly influencing weight gain, via causing us to crave high fat and high sugar foods.
What can you do?
Better gut health = better overall health.
Fortunately, we do have some control over those billions of bacteria nesting in our gut, via deliberately altering what we eat. Measurable changes in our gut bacteria can occur within 24 hours of changing our diet. To improve your gut bacteria, simply eat more plants, specifically those high in fibre and prebiotics, consume foods rich in probiotics, and limit processed sugars and alcohol.