Gut Health and Energy: How Your Digestive System Plays a Role

How the digestive system supports energy production

Behind the digestive system and energy production is a multi-stage process for absorbing and converting the nutrients in food. Your body begins preparing for digestion as soon as it sees or smells food. It starts with saliva and continues through the stomach and into the digestive tract, with most nutrient absorption taking place in the small intestine. There, proteins are broken down into amino acids, lipids (fats) into fatty acids, and complex carbohydrates into simple sugars such as glucose. These make their way in more usable forms to our cells, where they fuel the cells’ “power plant,” the mitochondria. Ultimately, this produces ATP (adenosine triphosphate), the body’s “energy currency.”¹
Maximizing the amount of energy captured depends on the availability of oxygen and essential vitamin and mineral cofactors.²

How digestive health influences your energy levels

Beyond basic nutrient extraction, a healthy gut contributes to energy levels by producing bioactive metabolites and influencing key messengers (metabolic hormones). More on those below.

Short-chain fatty acids (SCFAs)

SCFAs act as the gut’s secondary fuel source. When we eat high-fiber foods, our gut bacteria ferment the non-digestible fiber, converting it into SCFAs. These molecules provide fuel for cells that maintain the gut barrier’s integrity, supporting a balanced gut.³ SCFAs can also contribute to the liver’s production of glucose, the body’s primary energy source.⁴

Signaling and metabolic activation

SCFAs also act as signaling molecules that “turn on” important enzymes in the liver and muscles, including AMPK (AMP-activated protein kinase).⁵ This enzyme is like a cell’s low-fuel gauge.⁶ AMPK plays an important role in the body burning fat for fuel rather than storing it.⁷

Neurotransmitter synthesis and mental energy

The gut produces the large majority of the body’s “happy hormone,” serotonin, and significant amounts of dopamine and the neurotransmitter gamma-aminobutyric acid (GABA). While these molecules remain in the gut to function locally, they can interact with the vagus nerve and the gut-brain axis and impact energy, motivation, and the sleep-wake cycle.^8,9,10

Digestive discomfort is commonly linked to low energy

Digestive discomfort like bloating, occasional discomfort, and irregularity is often accompanied by low energy. Poor digestion and low energy could be signs of an unbalanced gut microbiome.¹¹ If you're experiencing persistent digestive discomfort alongside low energy, talk to your healthcare provider.
Learn more about the causes of low energy in men and women.

How gut health affects energy levels throughout the day

Your gut health and energy level impact each other in a cycle that can be positive or negative. Lack of sleep, certain eating habits, and gut imbalance can snowball without intervention, leading to low energy.

Circadian rhythms

Just like our bodies have internal rhythms, so do our gut microbes. Your microbiome’s activity changes throughout the day to align with your sleep-wake cycle.¹² Emerging research suggests that the microbiome helps synchronize the hypothalamic-pituitary-adrenal (HPA) axis.¹³ This system releases cortisol, a hormone that helps you wake up and start your day.
Poor sleep or disrupting behaviors like late-night eating can disrupt microbial rhythms as well as cortisol peaks.^14,15 This, in turn, can make you feel groggy in the morning or wide awake at night.

Post-meal sleepiness

Anyone who’s ever experienced a “food coma” knows that what you eat can cause sleepiness. Increased insulin released to clear the glucose also shifts certain amino acids, leaving a higher ratio of tryptophan in circulation.¹⁶ The brain converts this into serotonin, which signals the brain via the vagus nerve that you are full and can shift from an alert state to a “rest and digest” (parasympathetic) state by slowing heart rate and redirecting blood flow.¹⁷
Plus, highly processed foods or those high in saturated fats can temporarily increase cytokines, which are associated with tiredness.¹⁸

The gut-brain axis and sleep

Sleep is when the body recharges its energy stores, and a balanced gut is a key factor in sleep quality. Certain strains of Lactobacillus and Bifidobacterium can produce GABA and influence serotonin signaling in the gut.¹⁹ SCFAs produced by other microbes can also stimulate specialized gut cells to increase serotonin production.²⁰ Through their interaction with the gut-brain axis, these molecules may influence relaxation and sleep quality. When your microbiome is unbalanced, your sleep can suffer. This, in turn, negatively impacts your microbiome in a cycle that can leave you feeling tired.

Ways to support gut health for better energy

Supporting energy levels begins with eating a nutrient-rich diet of whole foods. The right foods provide the essential macro- and micronutrients needed to produce ATP, which helps your body perform at its best. This also includes supporting gut health by feeding your microbiome and protecting the intestinal barrier.

The best way to nurture a balanced gut is to incorporate a diverse range of dietary fiber sources. These prebiotic foods feed beneficial bacteria, resulting in SCFA production.²¹

Good prebiotic sources include beans (chickpeas, lentils), seeds (chia, flaxseeds), nuts (almonds, pistachios), fruits (apples, bananas), vegetables (onions, leeks, asparagus), and whole grains (oats, barley).^22,23

In addition to prebiotics, try integrating probiotics—live bacterial strains that can help support your gut health. Probiotics are often found in fermented foods and drinks, including some yogurt, sauerkraut, cottage cheese, kefir, and kombucha. Just confirm that the label specifies “live cultures.”

For other ways to feel more energized, read our guide to increasing energy levels.

Foundational nutrition supplements for gut health

While there’s no substitute for a nutrient-rich diet of whole foods, a daily Foundational Nutrition supplement like AG1 can be a convenient, helpful addition to support gut health. With over 75 vitamins, minerals, and whole-food-sourced ingredients, plus probiotics, AG1 helps fill common nutrient gaps, supporting gut health and overall wellness.

References:

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