Gut Microbiota Hindering Your Fitness Progress?

We have all heard the expression, “you are what you eat,” and we have all certainly understood the validity of this expression at some point or another. Generally speaking, when we eat junk, we feel like junk. When we eat natural, clean, nutrient-dense foods, we feel energized and rejuvenated.

However, new research has revealed that this phrase might deserve more of a literal interpretation than previously thought: As it turns out, our gut microbiota is drastically altered by the foods, drinks, medications, environmental toxins, and stresses which we are exposed to on a daily basis. Furthermore, the bacterial balance which arises as a result of our daily habits can actually influence our physical—and even emotional—state, for better or for worse.


Your gut microbiota is the bacterial ecosystem that lives in your intestinal tract. According to Nutrition in Clinical Practice, the typical healthy person has trillions of organisms like bacteria, fungi, and viruses in their gastrointestinal system that can exert a number of benefits on his or her health. What’s more is that these bacteria contain more than 100 times more genes and genetic material than you do. In other words, bacterial DNA outnumbers your own by more than 100 times.

The highly complex ecological system contained in the gut not only digests the foods you consume, extracts nutrients, and separates waste, but it also ensures that your immune system and metabolism are well-regulated, sustains the gastrointestinal tract, boosts cognitive health and function, and supports your mental well-being. Your gut flora is even responsible for generating certain vitamins and catalyzing chemical reactions, making a proper balance vital for optimum performance. Bacteria situated in the colon, for example, are responsible for creating energy in the form of short-chain fatty acids (primarily acetate, propionate, and butyrate) that may help treat inflammatory bowel disease, protect against colon cancer and heart disease, regulate blood sugar, and boost athletic performance. With the many intricacies of this delicate ecosystem, it’s no wonder then that keeping close tabs on the health of your gut is vital if you are looking to improve your weight, mood, and overall fitness.

The complicated part in regard to the realm of gut health is that not all bacteria in our gut is beneficial. In fact, studies have shown that an imbalance of “bad” and “good” bacteria plays a significant role in the onset of a number of diseases, including gastrointestinal conditions, obesity, diabetes, autoimmune disorders, and several others.

You see, since one of the main roles of good bacteria is to stop pathogenic bacteria from adhering to the walls of the gastrointestinal tract, an imbalanced ratio of good bacteria to bad bacteria can lead to the adhesion of pathogens commonly associated with ailments like irritable bowel syndrome and intestinal permeability (AKA leaky gut). These previously stated conditions decrease nutrient utilization, which in turn means you could be taking in expensive supplements and organic foods without truly reaping all of the health benefits.

Furthermore, if microbiota levels are out of sync, the overpopulation of bad bacteria can result in substantial increases in a molecule known as lipopolysaccharide, or LPS. Located on the cellular surface of bacteria, LPS is responsible for triggering natural immune system responses within the body that can then lead to inflammation and insulin resistance. Simply put, having bad bacteria to accompany the good is essential and inevitable. What matters, however, is the amount and ratio of each of these types of bacteria in relation to the other. Oftentimes, lacking good bacteria in your gastrointestinal tract sets up the perfect environment for illness to thrive—and as a result, your fitness level plummets.


Our bodies are excellent communicators when we pay attention to the messages they are trying to send. There are a number of ways in which you can tell if your gastrointestinal tract is overpopulated by bad bacteria:


  • You eat a healthy diet but struggle to progress in your fitness pursuits
  • You get sick relatively easily
  • You gain weight easier than most or struggle with weight loss
  • You have sore joints
  • You suffer from severe fatigue
  • You suffer from allergies, food sensitivities, and autoimmune symptoms
  • You suffer with gastrointestinal issues


Thankfully, our guts are responsive to change; however, this fact has both negative and positive implications. On the one hand, eating junk food, experiencing high levels of stress, and taking antibiotics that wipe out both harmful and beneficial bacteria can negatively alter the delicate balance of microbes in your gastrointestinal tract. Conversely, your gut responds well to healthy lifestyle changes too, and it is happy to become more positively balanced when you give it what it needs.

To illustrate the incredible responsiveness of the gut, we turn to a fascinating study on mice which was published in Science. In the study, researchers raised genetically identical mice in a germ-free environment so that their guts were void of any bacteria. These mice were then divided into two groups. One group of mice was implanted with microbes that had been extracted from obese women, and the second group of mice received the flora that had been collected from lean individuals. The researchers discovered that although the mice maintained the exact same diet, those who received bacteria from the obese donors grew heavier and accumulated more body fat than the mice who had received microbes from thin individuals. Interestingly, the study additionally found that the overweight mice had a less diverse community of microbes than that of the thin group. Translation: The balance and diversity of our gut flora can have a direct influence on our weight and body composition.


Clean up your diet – Bacteria are the first things to come into contact with the foods, liquids, nutrients, and supplements we consume, so naturally our diet affects these bacteria tremendously. Consuming an abundance of unhealthy foods (packed full of salt, sugar, trans-fats, and artificial chemicals) not only deprives your body of key nutrients, but furthermore, this practice is capable of killing off beneficial bacteria. Consume fresh, healthy, nutrient-dense foods and minimize the amount of junk you eat to improve the overall state of your gut—and health in general.

Consume probiotic supplements – Probiotics come in pill, capsule, or powdered form and are packed with billions of individual microbes that help to restore natural microbiota levels within us. The concentration of each probiotic capsule is expressed as CFUs (colony forming units). In most cases, it is recommended to consume a daily probiotic containing between 5-10 billion CFUs.

Fermented foods – When developing a well-rounded nutritional program, probiotic-rich foods are a must due to their incredible healing and performance-boosting properties. Whether you are a weekend warrior or an elite athlete, fermented foods should be included as a staple in your diet in order to attain peak fitness levels. Fermented foods are jam-packed with beneficial bacteria and natural energy sources. Raw sauerkraut, for example, is pickled and fermented via a process known as lacto-fermentation. During this lacto-fermentation process, the beneficial Lactobacilli bacteria consume the natural sugars contained within the vegetable and then consequently convert them into lactic acid and other forms of energy that benefit your gastrointestinal tract. Other popular examples of fermented foods and beverages include: kefir (fermented milk), kombucha (fermented tea), whey (liquid portion of kefir), kimchi (spicy pickled cabbage), natural yogurt, and various pickled vegetables. It is important to note that most grocery store versions of the foods listed above are pasteurized (unless specifically stated otherwise), which kills off the beneficial probiotics found in these products. Fortunately, these foods are relatively easy to make at home with few supplies. Additionally, a variety of raw, unpasteurized options can generally be found at your local health food store and farmers’ market.

Eat more veggies – As of 2015, a national U.S. study revealed that fewer than 18% of adults in each state consume the recommended five servings of fruits and vegetables each day. This fact is concerning given that produce—particularly leafy greens—provides our gut bacteria with a healthy source of energy. Remember, our gut flora needs to consume food as well, and the type of food we feed it greatly affects how well it will function—and as a result, how well you will perform.


Overlooking the importance of the ecological system contained within your gut can have serious implications regarding your overall fitness level. The gut has received a great deal of attention in the health community in recent years due to newfound discoveries of its link to gastrointestinal diseases, autoimmune conditions, and mood disorders; however, the role the gut microbiota plays in terms of athletic performance has been discussed much less readily. While many of us in the fitness community tend to overlook the complexity and importance of this organ, feeding our bodies with healthy, nutrient-dense foods, reducing stress and toxin exposure, and reinoculating the gut with beneficial bacteria can have amazing effects on our physical, mental, and emotional well-being—all 3 of which are essential in the realm of fitness.

In order to perform at peak levels, it is absolutely critical to enhance nutrient absorption and utilization. While calories remain a key consideration while constructing any meal plan, it is even more vital to pay attention to the quality and nutrient content of each food—all calories are not created equal. To truly maximize function and improve physical fitness, each particular food must be examined for its cumulative effect on both hormone and gut flora balance. In a world where the difference between winning and losing often times comes down to milliseconds and/or inches, gut optimization is exactly the edge you need!

Nutrition in Clinical Practice, Volume 30 Number 6, December 2015, 734 – 746. American Society for Parental and Enteral Nutrition