Key Points:
- What the gut microbiome is and why the large intestine plays such an important role.
- NASM Certified Nutrition Coach Eugene Pallisco explains the signs of poor gut health and how diet affects gut bacteria.
- Which foods harm or support the gut microbiome and how to track your gut health.
“Gut health” and the “gut microbiome” have exploded into the mainstream, appearing everywhere from diet plans to supermarket shelves. Unlike many wellness trends, there’s a growing body of research behind them.
According to Eugene Pallisco, a NASM Certified Nutrition Coach and Personal Trainer, the gut sits at the center of a chain reaction that reaches far beyond digestion. “Gut health is connected to your immune system, inflammation, metabolism, mood, cognition, and chronic health conditions,” he explained.
Here’s what you need to know about your gut, why it matters, and how to keep it healthy.
Table of Contents
What Exactly Are Gut Health and the Gut Microbiome?
The gut isn’t one organ. It’s the entire digestive tract, running from the mouth through the stomach and intestines to the rectum and anus. When people talk about gut health or the gut microbiome, they’re mainly talking about the large intestine, where the greatest concentration of gut microbes live.
“The gut microbiome is the community of trillions of bacteria, viruses, fungi, and other microorganisms living in the digestive tract. They interact with the food you eat and play a role in digestion, metabolism, and immune function, “ Pallisco says.
Large Intestine vs. Small Intestine
Most digestion and nutrient absorption happen in the small intestine. By the time food reaches the large intestine, your body has already absorbed most of the nutrients.
Only water, undigested food, fiber, and resistant starches are still left. This is when gut microbes break down and ferment this material to produce compounds that provide energy, protect the gut lining, support the immune system, and regulate inflammation.
What Are the Signs of Poor Gut Health?
The gut is closely connected to the immune system, metabolism, and brain, so problems in the gut can trigger a chain reaction throughout the rest of the body. An unhealthy balance of gut bacteria can mess with digestion, increase inflammation, interfere with immune function, and affect communication between the gut and brain. These effects can then show up in your mood, skin, energy levels, and weight.
Look out for:
- bloating and gas happening often
- constantly feeling tired no matter how much sleep you get
- mood changes
- headaches or migraines
- skin problems like acne, eczema, rashes, or irritation
- unexplained weight changes
- craving sugar-rich foods like soft drinks or desserts and refined carbohydrates
Foods That Are More Likely to Negatively Affect Your Gut Health
There isn’t one food that will suddenly destroy your gut health. The bigger issue is how much and how frequently you eat certain foods. Unfortunately, many of the worst foods for gut health are cheap, convenient, highly processed, and easy to overconsume.
Fiber is one of the most important nutrients for gut health because beneficial bacteria feed on it. Foods high in saturated fat, salt, refined carbohydrates, added sugar, and certain additives provide little to no fiber and feed harmful bacteria instead. Over time, this can shift the microbiome toward an unhealthy balance, reduce beneficial bacteria, and increase inflammation.
Foods worth limiting include:
- Processed meats: Bacon, sausage, hot dogs, and salami are low in fiber and high in saturated fat, salt, and preservatives.
- Ultra-processed snack foods: Chips, cookies, candy, and packaged baked goods are low in fiber and high in refined carbohydrates, fats, salt, sugar, and additives.
- Sugar-sweetened drinks: Soda, energy drinks, sweet tea, and other sugary drinks deliver large amounts of sugar with virtually no fiber.
- Refined carbohydrates: White bread, pastries, sugary cereals, and cakes have had much of their natural fiber removed, leaving beneficial gut bacteria with less fuel.
- Deep-fried and high-fat fast foods: French fries, fried chicken, burgers, and similar fast foods are low in fiber and high in saturated fat and salt.
What Foods Support a Healthy Gut?
If fiber is the magic word, then fiber-rich foods are the fuel that feeds a healthy gut. Polyphenols are another important food source for gut bacteria, helping beneficial microbes grow and thrive. Fermented foods work differently. They contain live microorganisms that introduce additional microbes into the digestive system rather than simply feeding the ones already there.
Here are some of the best foods to include:
- Seeds: Chia seeds and flaxseeds are extremely rich in fiber. Just two tablespoons of chia seeds provide around 10 grams of fiber.
- Legumes: Beans, lentils, chickpeas, and peas are some of the richest everyday sources of fiber.
- Whole grains: Oats, barley, brown rice, quinoa, and whole-grain breads provide fiber that feeds gut bacteria.
- Vegetables: Broccoli, Brussels sprouts, artichokes, onions, garlic, carrots, and leafy greens provide fiber along with a wide range of plant nutrients.
- Polyphenol-rich foods: Berries, cocoa, coffee, tea, olive oil, nuts, herbs, and colorful fruits and vegetables provide plant compounds that beneficial gut bacteria use and interact with.
- Fermented foods: Yogurt, kefir, kimchi, sauerkraut, miso, and tempeh contain live microorganisms that can add to the microbes entering your digestive system.
How Can You Measure Your Gut Health?
There isn’t one test that can give you a definitive gut-health score. At-home microbiome tests can identify bacteria and other microorganisms in a stool sample, but they’re less useful for telling the average person whether their gut is simply “healthy” or “unhealthy.”
For most people, the easiest measurement is how well your digestive system is working. Pay attention to your bowel movements, bloating, gas, stomach discomfort, and how well you tolerate different foods. Regular, comfortable digestion with few ongoing problems is one of the clearest everyday signs that your gut is functioning well.
Key Takeaways:
- Poor gut health can show up through digestive problems, fatigue, mood changes, skin issues, and weight changes.
- A low-fiber diet high in processed foods and added sugar can disrupt the balance of gut bacteria.
- Eating more fiber, varied plant foods, and fermented foods is one of the simplest ways to support gut health.
About Eugene Pallisco
Eugene Pallisco is a NASM Certified Personal Trainer and Nutrition Coach based in Dallas, Texas. He specializes in strength training, body composition, nutrition, and sustainable fitness, helping clients build healthier habits and improve their long-term health through personalized training and nutrition guidance.