Last week, someone in my network asked me: “How do I improve my gut bacteria? I need to lose weight and feel healthy.”
That thoughtful question inspired this new series.
Here's Part 1
Let’s start with what we know about the link between gut bacteria and body weight.
Think of your gut as a densely populated neighborhood; home to trillions of micro organisms, mostly bacteria, along with fungi and viruses.
These tiny neighbors don’t just take up space; they actively influence how your body digests food, stores fat, and even how hungry or full you feel.
A few years ago, researchers conducted a fascinating experiment:
They transferred gut bacteria from regular mice into germ-free mice (mice which have no gut bacteria).
Even though these germ-free mice ate less, they gained more fat and developed insulin resistance!
It was one of the first strong clues that gut bacteria influence metabolism in ways we’re still learning to fully understand.
We often hear about two main groups of gut bacteria associated with weight and metabolism:
Firmicutes and Bacteroidetes.
Some studies show people with obesity tend to have more Firmicutes and fewer Bacteroidetes.
But other studies show the opposite. That’s because the relationship between your microbiome and weight is complex, there’s no one-size-fits-all pattern.
What we do know is that gut bacteria can affect weight in several important ways.
First, they help transform bile acids.
Certain bacteria like Bacteroides, Eubacterium, and Clostridium modify how your body digests and absorbs fats.
They also ferment undigested carbohydrates to produce short-chain fatty acids aka SCFA i.e. acetate, propionate, and butyrate.
These SCFA aren’t just passive byproducts.
They can supply up to 10% of your daily energy needs and improve insulin sensitivity.
These SCFAs also trigger the production of peptide YY (PYY), a hormone that tells your brain you're full – help you feel full, reduces your appetite, and slows stomach emptying.
Another layer: Some gut bacteria are really good at extracting energy from food.
That means two people eating the same meal might absorb different amounts of calories, depending, in part, on their microbiome.
To be continued Next week -
Thanks for reading, and as always—keep spreading knowledge wrapped in kindness
Note: This article simplifies current scientific understanding for general awareness. Individual responses vary.
Please consult with your healthcare provider before making significant diet or lifestyle changes.
links to reference scientific papers is included in the comments section.