It's common to hear about the importance of nutrition as fuel for training and recovery. But there is a true invisible command center connecting what we eat, how we feel, and even how we move: the gut.
This is where the gut microbiota lives, an ecosystem made up of billions of microorganisms (bacteria, viruses, and fungi) inhabiting our intestines. The microbiome, in turn, refers to the genetic material of all these microorganisms.
These microorganisms are far from being mere “passengers.” They actively participate in fundamental processes: helping with digestion and nutrient absorption, producing compounds with energetic effects and communicating with the brain through the so-called gut-brain axis. Science is beginning to reveal something even more interesting: this dialogue not only influences muscle function and performance but may also affect our motivation and willingness to train.
This is why a healthy gut often translates into more energy, better recovery, and greater consistency in movement.
The Gut: More Than Digestion
If the body were a team, the gut would be the silent player who doesn’t make the headlines but without whom the game cannot happen.
It is where:
👉 We absorb essential nutrients for performance – such as iron, vitamin B12, calcium, vitamin D, magnesium, and zinc. When the intestinal mucosa does not function properly, absorption of these nutrients may be compromised, resulting in less energy, greater fatigue, and reduced training efficiency.
👉 Microorganisms produce vitamins and small molecules called short-chain fatty acids (SCFAs)—such as butyrate, propionate, and acetate. We can think of them as silent fuel: they nourish the intestinal cells, help maintain stable blood sugar levels, and reduce inflammation.
👉 It builds a significant part of our immunity—and when the intestinal barrier is weakened, symptoms such as fatigue, lack of concentration, increased infection risk, and even lower motivation to train may arise.
When the microbiota's balance is lost, the signs become evident: digestive discomfort, persistent tiredness, mood alterations, performance decline, and greater susceptibility to infections.
What Science Has Already Shown Us
👉 Moderate exercise promotes microbial diversity and improves immune function.
👉 Excessive exercise, without adequate recovery, can increase intestinal permeability, cause inflammation, and lead to gastrointestinal symptoms.
👉 A balanced microbiota is linked to better nutrient absorption, quicker recovery, and greater mental resilience.
👉 The relationship between exercise and microbiota is bidirectional: while physical activity promotes beneficial bacteria, a healthy gut can, in turn, enhance exercise capacity through mechanisms such as better energy metabolism, reduced inflammation, and improved hormonal balance.
👉 Animal model studies suggest the microbiome may influence motivation for exercise through dopamine regulation. In humans, this connection is still under investigation, but results are promising.
Nutrition: How to Nourish the Gut and Performance?
This isn’t about following fads but applying practical strategies that support the body and training over the long term:
👉 Include prebiotic fibers—found in foods like oats, slightly unripe banana, apple, legumes, cooled potatoes or rice, or even cabbage and turnip greens. These feed beneficial bacteria and promote SCFA production.
👉 Include fermented foods—such as yogurt with live cultures, kefir, sourdough bread, sauerkraut, kimchi, or tempeh. These can help increase microbial diversity, though effects vary depending on type and quantity.
👉 "Train the gut" during long training sessions: gradually introduce the carbohydrates (gels, drinks, snacks) to be used in competitions to improve tolerance and prevent discomfort.
👉 Targeted adjustments before competitions: temporarily reducing foods high in FODMAPs may decrease symptoms like bloating or urgent bowel movements without compromising energy.
👉 Sleep, hydration, and stress management: silent but crucial factors that influence both the microbiota and recovery and performance.
New Dietary Trends in Sport and Their Impact on the Gut
In recent years, bars, cookies, and protein drinks, often sweetened with polyols (maltitol, sorbitol, erythritol, xylitol), have become popular. These sweeteners have some advantages: they provide fewer calories than sugar and, in small amounts, can even stimulate beneficial gut bacteria. They are practical and can be a useful aid, but as with everything, dosage matters. Excessive polyols reach the colon without being fully absorbed, where they are fermented by gut bacteria—which can result in gas, bloating, and diarrhea. Animal studies suggest changes in the microbiota with high and prolonged consumption, but evidence in humans is still limited. However, it is well agreed that excess can cause discomfort and impair training or competition.
Another point to consider is the excess protein found in some sports-related diets. When protein intake is very high and not accompanied by enough fiber and antioxidants, it can negatively impact the gut microbiota, reduce bacterial diversity, and increase inflammation risk. Additionally, lack of vegetables and fruit limits bioactive compounds important for recovery and long-term health.
The foundation should continue to be a varied diet rich in vegetables, fibers, and natural foods. “Fit” and protein products can supplement but should not replace the pillars that support a healthy gut and consistent performance.
Less Fads, More Consistency
In recent years, many trends promising quick gains in performance or health have emerged—low-carb diets, protein or ‘fit’ products often sweetened with polyols and enriched with other additives are just some examples. While many may be practical and even useful at certain times, they do not replace what truly supports the body over the long term.
A healthy gut is built with consistency but also with flexibility: a diet adapted to each person’s individuality, rich in plant-based and fermented foods according to personal tolerance. When combined with proper hydration, quality sleep, and adjusted training, this foundation creates the ideal environment to nourish the microbiota, support recovery, and keep body and mind balanced.
This is why gut health is a silent pillar of performance: a balanced microbiota can make the difference between training with energy or dragging oneself, recovering quickly or accumulating fatigue, maintaining motivation or constantly struggling.
By caring for the gut, we care not only for digestion but also for energy, concentration, immunity, recovery, and even emotional balance—factors that can contribute to more enjoyable and consistent training.
❓ Frequently Asked Questions
1. What is the gut microbiota?
It is the collection of microorganisms (bacteria, viruses, and fungi) inhabiting the gut, involved in processes such as digestion, nutrient absorption, energy production, and immune regulation.
2. How does the microbiota influence sports performance?
A balanced microbiota improves nutrient absorption, reduces inflammation, supports immunity, and contributes to increased energy, faster recovery, and better motivation to train.
3. Which foods help maintain a healthy microbiota?
Foods rich in prebiotic fibers (oats, slightly unripe banana, apple, legumes), vegetables, fruits, and fermented foods such as kefir, yogurt with live cultures, sauerkraut, or sourdough bread.
4. Can physical exercise alter the gut microbiota?
Yes. Moderate exercise promotes microbial diversity and gut health. Excessive training without adequate recovery can weaken the intestinal barrier and increase gastrointestinal symptoms.
5. Can the microbiota influence the motivation to train?
Animal studies suggest yes, through dopamine regulation. In humans, research is ongoing but indicates a promising connection.
6. What happens when the microbiota is imbalanced?
Symptoms such as fatigue, digestive discomfort, mood changes, increased infection risk, and decreased physical performance may arise.
7. Are supplements or “fit” products enough to care for the microbiota?
No. They may be useful in certain contexts but do not replace a varied and balanced diet rich in vegetables, fibers, and natural foods.
📌 About the Author
Rita Marques is a nutritionist passionate about helping people find balance between body, mind, and nutrition. With practical experience in the sports world and a focus on individuality, she writes for BOOMFIT on topics related to functional nutrition, performance, and well-being.
