While fitness professionals focus on training and nutrition, understanding the gut’s role in metabolism can unlock better client results

As gyms, studios and trainers continue advancing in technology, equipment, and programming to optimize member outcomes, one critical factor often goes overlooked: gut health.

Every trainer has seen it — a committed client who follows the plan yet struggles with hunger, energy fluctuations, bloating or weight management. The gut microbiome plays a pivotal role here, yet its significance is often misunderstood.

So how can fitness professionals help clients bridge the gap between gut health, metabolism and sustainable fitness results?

ATN consulted with Pendulum, a pioneering company in microbiome solutions, to explore the gut’s role in metabolism, the connection between GLP-1, exercise, and digestion, and how trainers can guide clients toward better outcomes.

Gut Microbiome 101

According to Kara Siedman, Senior Manager of Scientific Communications at Pendulum, the gut microbiome is a critical regulator of metabolism, cravings and energy levels. It influences digestion, nutrient absorption, hormone production and inflammation, which are all key processes that determine how efficiently the body regulates weight, appetite and overall metabolic health.

She explains, “A healthy microbiome, rich in beneficial bacteria like Akkermansia muciniphila and butyrate-producing species, helps maintain a strong gut barrier and reduces inflammation —  both in the gut and beyond. These bacteria support the production of GLP-1, a hormone that regulates blood sugar and appetite, strengthens the gut barrier, reduces inflammation and supports gut repair.”

In short, when the microbiome is balanced, metabolism functions efficiently, helping to prevent weight gain and blood sugar imbalances.

Conversely, when the microbiome is imbalanced —  a condition known as dysbiosis —  metabolic health can suffer. “Dysbiosis weakens the gut barrier, allowing harmful bacteria and toxins to enter the bloodstream, triggering inflammation,” she says. “And chronic inflammation is a major driver of metabolic dysfunction, contributing to insulin resistance, weight gain and energy instability.”

Beyond metabolism, the microbiome also influences cravings and appetite regulation via the gut-brain axis. 

“Beneficial bacteria promote the release of hormones like GLP-1 and PYY, which help increase feelings of fullness and reduce hunger,” says Siedman. “But when the microbiome is out of balance, cravings for sugar and processed foods can increase, further disrupting metabolic health.”

Signs a Client May Need to Prioritize Gut Health

Given the microbiome’s far-reaching impact, how can fitness professionals recognize when a client may benefit from focusing on gut health as part of their fitness journey? While every individual is different, certain recurring patterns may indicate an imbalanced microbiome. Trainers should be aware of these common signs:

• Frequent bloating, irregular digestion and gastrointestinal distress – Chronic bloating, constipation or discomfort after eating can signal an imbalanced gut.
• Unstable blood sugar levels leading to crashes and fatigue – Poor gut health can impact glucose regulation, causing energy highs and lows.
• Slower muscle recovery and prolonged soreness – A compromised microbiome can lead to increased inflammation, delaying post-workout recovery.
• Increased susceptibility to colds and infections – Since much of the immune system is housed in the gut, a weakened microbiome can impair immune function.
• Disruptions in sleep quality and mood regulation – The gut-brain connection influences neurotransmitters like serotonin, affecting sleep and mental well-being.

If clients are displaying these symptoms on a recurring basis, it may be time to consider a probiotic.

Recognizing the essential role of the microbiome, Pendulum has developed a targeted probiotic designed to enhance gut health and naturally support GLP-1 production.

“Pendulum GLP-1 Probiotic is a multi-strain, live probiotic featuring advanced strains like Akkermansia muciniphila, Clostridium butyricum, and Bifidobacterium infantis,” Siedman explains. “Each of these strains plays a critical role in promoting gut and metabolic health.”

So, how do these strains work together to support metabolism?

Akkermansia muciniphila, a key strain in the formula, strengthens the gut barrier, reducing intestinal permeability (often referred to as “leaky gut”). This prevents harmful substances from entering the bloodstream and triggering systemic inflammation that disrupts metabolic processes. “Akkermansia produces important metabolites such as propionate, which helps regulate metabolism, and p9, a protein that directly stimulates GLP-1 production,” says Siedman.

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Clostridium butyricum produces butyrate – a short-chain fatty acid essential for metabolic regulation. “Butyrate plays a crucial role in gut integrity and inflammation control, helping to support overall metabolic function,” she adds.

Finally, Bifidobacterium infantis helps break down dietary fibers in the early stages of fermentation, creating the right environment for other beneficial bacteria like Akkermansia to thrive.

Pendulum’s research on the GLP-1 Probiotic has shown promising real-world results. In a consumer survey of over 270 participants who took the probiotic for six weeks, 91% reported a reduction in food cravings, with cravings for sugar, fat, and salty foods dropping by over 80%. Additionally, clinical research on Pendulum’s Glucose Control formula, which contains these same core strains, demonstrated a 33% reduction in glucose spikes and improved long-term blood sugar control after 12 weeks.

Common Pitfalls & Misconceptions

The science behind probiotics and metabolism is complex, and misinformation can lead to some misconceptions about gut health. Following are some common pitfalls fitness professionals should be aware of:

• Exercise alone does not guarantee gut health. Even highly active individuals can experience microbiome imbalances that impact metabolism and recovery.
• Intense training can stress the gut. Prolonged exercise can increase gut permeability, triggering inflammation and metabolic disruptions.
• Highly processed “fitness foods” may harm the microbiome. Many protein bars and shakes contain additives that degrade gut barrier integrity.
• Gut health affects performance. Poor gut health can lead to slower recovery, fatigue, increased inflammation, and greater susceptibility to illness.

“Gut health is not just about diet and exercise, it’s about resilience,” explains Siedman. “Fitness professionals should be aware that training stress, recovery habits, and supplementation choices all can have an impact on gut microbiome stability. Optimizing gut barrier integrity, reducing inflammation, and supporting our beneficial microbes is key to sustaining metabolic health, performance, and long-term well-being.”

How Fitness Professionals Can Integrate Gut Health into Client Education

While fitness professionals cannot prescribe probiotics, they can play a key role in educating clients about the connection between gut health, metabolism, and performance.

“Trainers should focus on lifestyle factors that naturally support GLP-1 production,” Siedman advises. “Encouraging clients to eat fiber-rich foods, stay active, manage stress, and get quality sleep all contribute to gut health.”

Additionally, guiding clients to research-backed probiotics, such as those with Akkermansia muciniphila, can be beneficial. “It’s important to look for probiotics that have been scientifically studied, rather than just focusing on individual ingredients,” she notes.

In the end, recognizing the importance of gut health and encouraging clients to adopt healthy habits that support it is a great start, and referring them to professionals when necessary for personalized advice is a smart next step.