A balanced gut microbiome helps regulate how you harvest energy, store fat, and control appetite. But when that balance shifts (thanks to stress, antibiotics, or ultra-processed diets), it can work against you.
Certain gut bacteria are “super-efficient” at extracting calories, meaning two people can eat the same meal but absorb different amounts of energy.
Gut dysbiosis also disrupts gut hormones like GLP-1 and PYY, and increases inflammation, which messes with insulin and leptin — the hormones that tell your body when to burn or store fat.¹²³ It’s hard to tell how common this is, but the point is, there’s no harm in optimizing your gut microbiome!
Bottom line: an unbalanced microbiome can quietly stall your weight loss efforts.
Two of my favorite books, and references, as I was writing Constipation Nation, help here.
As Dr. Emeran Mayer explains in The Mind-Gut Connection, your gut and brain are in constant conversation through nerves, immune messengers, and microbial metabolites.⁴
– Around 90% of serotonin is made in the gut.
– Gut microbes produce brain-active chemicals like dopamine and GABA.
– Inflammation from a “leaky gut” can cross into the brain, disrupting focus and mood.
Ed Yong puts it beautifully in I Contain Multitudes: “We are an assemblage of many species, and their whispered chemical conversations can shape our thoughts and behaviors.”⁵
If you’ve ever felt brain fog during a gut flare-up, this is why. Restore the gut, and mental clarity often follows.
Roughly 70% of your immune system lives in your gut. My kids have a book about vaccines. In simple terms, it means that the good ‘germs’ train your body’s little immune cell army to recognize them so that when they approach the gate waving a white flag, no one gets shot. But when bad germs approach, without a white flag, the immune cell army goes to war. In this way, beneficial microbes train immune cells to recognize friendly bacteria and defend against real threats. When the microbiome is imbalanced, this training falters — making you more prone to inflammation, infection, or even autoimmune misfires.⁶
Think of it as immune boot camp: without good instructors, the recruits get confused.
Your microbiome isn’t just about digestion. It influences how your body uses energy, how clearly you think, and how well you fight illness.
Small, steady changes make the biggest impact:
– Eat more fiber and plant diversity
– Cut down on ultra-processed foods
– Prioritize sleep and stress management
– Avoid unnecessary antibiotics
Healthy gut, healthy you.
