I discovered I really like to ferment foods. You know that feeling when you plant a seed in the ground and in a few days it sprouts? When you get that good feeling that you made it work while you see it grow into a plant? That's how I feel when I see those bubbles in the jar and taste it a few days later. The feeling that I helped transform the food into something more. Don’t get me wrong, it also went sideways, sooo many times.
Why am I telling you about this and why are these fermented foods with bubbly benefits?
Our body is host to elaborate forms indigenous biota, like all complex multicellular life-forms. We are basically a cumulation of many species, since in our bodies, bacteria outnumber our cells that contain DNA by more than 10 to 1. One place where they reside is our intestines where they break down nutrients we would not otherwise be able to digest for example.
We’ve all heard the saying “you are what you eat,” but science is now showing it’s more like “you are what your microbes eat.” Deep inside your gut, trillions of tiny organisms—collectively known as the gut microbiota—are doing much more than helping you digest food. They're part of a complex communication network with your brain, influencing your mood, hunger levels, energy use, and your immune system, to name a few.
Understanding how this system works gives us a powerful reason to pay attention to fermented foods, which help nourish these vital microbial communities.
Your gut: a living factory that nourishes you
Think of your gut like a thriving factory: you deliver raw materials (food), and the workers (microbes) turn them into useful tools for your health. These bacteria produce essential by-products like:
Short-chain fatty acids (SCFAs): These help reduce inflammation, regulate appetite, and support gut health.
Vitamins including some B vitamins and vitamin K.
Neurotransmitters such as GABA and serotonin-like compounds.
When your microbiota is healthy, it supports your immune system, helps manage weight, and even influences your emotions.
Gut microbes talk to your brain
The gut and brain are connected through the gut-brain axis—a two-way communication channel that allows your gut microbes to influence how much you eat, how much energy you burn, and how you store fat.
Here’s how this communication happens:
1. Microbial by-products as messengers
Microbes break down fibers into SCFAs like butyrate, acetate, and propionate. These work like messenger pigeons, flying through your bloodstream to tell your brain and body things like:
"You’re full now!" (via hormones like GLP‑1 and PYY)
“Burn more energy!” (by activating fat and muscle metabolism)
“Keep the gut lining strong” (by nourishing intestinal cells)
(Arora et al., 2024).
2. Bile acids and amino acids join the chat
Gut microbes modify bile acids, which help digest fats but also stimulate hormones that affect hunger and metabolism.
They also break down amino acids like tryptophan, producing compounds that may impact your mood and food cravings.
So, your gut microbes aren’t just breaking down food—they’re part of a feedback system that helps regulate your whole body.
How diet affects the gut-brain axis
What you eat directly shapes the microbial communities in your gut. Some foods build them up, while others tear them down.
High-fiber, plant-rich diets (think legumes, veggies, whole grains) fuel the good microbes that produce SCFAs.
Fermented foods (like sauerkraut, kimchi, and tempeh) introduce beneficial microbes and support microbial diversity.
High-protein diets increase satiety via gut hormones, but may not nourish gut microbes as well unless paired with fiber.
Low-carb, low-fiber diets may reduce microbial diversity, leading to poor gut-brain communication over time.
Important to note: this is general advice and that everyone reacts differently depending on the context. For example if there’s inflammation in the gut and / or SIBO then someone might not tolerate a high fiber diet. In addition, a carbohydrate rich diet might benefit active people more than a low-carb one. Hence the importance of personalisation and understanding how YOUR body works.
Real-life analogy: your body’s smart thermostat
Imagine your body is a cozy home with a smart thermostat. The food you eat is the fuel. Your gut microbes are the thermostat’s sensors, and the signals they send (via SCFAs and hormones) are like setting the temperature.
When the system works well, your body stays in balance.
When the gut microbiome is out of sync (e.g., from poor diet or antibiotics), it’s like the thermostat gets stuck: you feel hungrier, store more fat, and burn less energy.
Fermented foods help reset and fine-tune this smart system—keeping your body in homeostasis.
Takeaway: fermented foods help your gut help you
Fermented foods do more than taste good—they help your gut microbes send the right messages to your brain. With better microbial signals, your body naturally balances hunger, energy, and metabolism.
So next time you reach for food, think: Am I feeding just myself—or also my gut allies?
References
Han, H., Yi, B., Zhong, R. et al. From gut microbiota to host appetite: gut microbiota-derived metabolites as key regulators. Microbiome 9, 162 (2021). https://doi.org/10.1186/s40168-021-01093-y
Katz, S. E. (2012). The art of fermentation: an in-depth exploration of essential concepts and processes from around the world. Chelsea Green Pub.
Pürdik Tatık G, Baran Ö, Dağ A. Gut-brain axis: The role of gut microbiota in energy balance and body weight regulation. Clin Sci Nutr. (2025);7(1):55-62. doi:10.62210/ClinSciNutr.2024.98
Shockey K. K. & Shockey C. (2014). Fermented Vegetables: Creative Recipes for Fermenting 64 Vegetables & Herbs in Krauts, Kimchis, Brined Pickles, Chutneys, Relishes & Pastes. Storey Publishing, LLC
Yan Zhang, Rui Chen, DuoDuo Zhang, Shuang Qi, Yan Liu, Metabolite interactions between host and microbiota during health and disease: Which feeds the other?, Biomedicine & Pharmacotherapy, Volume 160, (2023) https://doi.org/10.1016/j.biopha.2023.114295