Following the Journey of Your Food: From Eating to Excreting

Written by Megan Falk: Experienced health and wellness journalist and editor. Megan is a graduate of Syracuse University’s S.I. Newhouse School of Public Communications, where she earned a bachelor’s degree in Magazine Journalism and a minor in Food Studies. She’s also a certified personal trainer through the American Council on Exercise.
Reviewed by Jennie O’Grady: Senior SciComms Specialist at Seed Health

As you know from personal experience, what goes in must come out. But what happens in between?

Digestion is a complex and carefully coordinated process involving trillions of bacteria and 20-30 feet of anatomical runway.^1,2 The journey is a bit like a game of Candy Land, with food snaking its way from your mouth to your anus—encountering highly acidic juices, voracious microbes, and plenty of brute force along the way. 

Let’s follow a piece of food through this winding road of your GI tract—and track what you can do to make its trip more smooth and comfortable.

Digestion Starts in the Mouth

Before you even take your first bite of food, its mouth-watering (literally) smell triggers the release of saliva.³ 

Your spit is about 99% water, but it also contains amylase and lipase—enzymes that kickstart the chemical breakdown of your grub from starches (aka complex carbohydrates) into simple sugars and lipids.⁴ 

With the help of molecules called mucins, saliva also lubricates and moistens food, making it easier to chew, compress into a bolus (the scientific term for “ball of food”), and swallow. At the same time, you mechanically break down your food in the process of chewing.⁴ 

How to support this step: Eat slowly

Despite what you may have been told at the childhood dinner table, there’s no “best” number of times to chew (and one study even found that excessive chewers rated their meal as less enjoyable).⁵ What’s more important is how quickly you chow down. 

Eating at a slower pace ensures that you’re breaking your food down into small enough pieces for the organs in the digestive tract to handle. It also gives your brain more time to receive hormonal cues from the stomach that signal it’s full. The release of these hormones, plus the suppression of the “hunger hormone” ghrelin, typically takes about 30 minutes.⁶

By eating slower and allowing this communication to play out, you’ll be less likely to eat past the point of fullness and over-tax your digestive system during the peptic pit stops to come.⁷

The Only Way Out Is Through the Esophagus

After you swallow, food traverses down your pharynx (aka throat) and into your esophagus, the 10-inch-long muscular tube that terminates in your stomach.¹¹ 

A phenomenon called peristalsis ensures that the esophagus is a one-way street. Through a series of involuntary, “wave-like” contractions, the muscles before the bolus contract and the muscles after it relax, pushing your food downward like a crawling caterpillar.^10,12,13 

Once it reaches the end of the esophagus, food eeks through a ring-like muscle called the lower esophageal sphincter (LES) to enter the stomach. This muscle temporarily opens and then shuts to trap food particles in your stomach for the next—and potentially most dramatic—stop of the journey.¹⁴ 

How to support this step: Watch out for triggers of acid reflux 

Sometimes, the LES relaxes too often or for too long, which makes it easier for stomach acid to escape into the esophagus. Hello, heartburn. Some foods (including chocolate, alcohol, and those high in fat) can all trigger the LES to relax, while others (e.g., caffeine, spicy foods) can stimulate the stomach to produce more acid, which can also increase the risk of reflux.¹⁵ 

Your dietary choices can also irritate the lining of the esophagus itself, especially if it’s already sensitive or inflamed.¹⁶ Foods that are acidic (like citrus fruits and tomatoes) can trigger this irritation, as can garlic and onions. You may also experience acid reflux after eating a large meal or a lot of foods that take longer to digest.¹⁷ 

With this in mind, if you are prone to reflux or stomach upset after eating, try eating smaller portions more frequently, limiting triggering foods like the ones mentioned above, and going for a walk or remaining upright after eating to lessen pressure on the LES.

A Quick Pit Stop in the Stomach

Your stomach is lined with cells that produce about 3 to 4 liters of highly acidic gastric “juice” per day.¹⁸ With a pH of 1.5-2.0, this juice is comparable to battery acid.¹⁰ Nothing is safe in this extreme environment—not even the stomach itself. To protect against this, the stomach generates a new coat of mucus regularly, serving as a physical barrier against its own corrosive cocktail.¹⁹

Your stomach muscles churn food in these exceptionally acidic juices until it becomes a semi-liquid mixture called chyme. The same peristaltic waves that move food down your esophagus then propel this mixture toward the small intestine. When all goes as planned, this process takes about three hours, with chyme exiting the stomach at a steady, well-regulated pace—a phenomenon known as gastric emptying.¹⁸

Gastric emptying is a meticulously controlled process that ensures nutrients are delivered to the small intestine at optimal rates for digestion and absorption. The speed of emptying depends on the type of food being processed: liquids typically empty rapidly in a steady, uniform manner. Solids must be broken down further (until they are no more than 1-2 millimeters in size) before they can pass through to the small intestine.²⁰

Several factors influence gastric emptying: Neural regulation via the vagus nerve plays a significant role, as do hormones like ghrelin (which stimulates gastric contractions and accelerates emptying) and glucagon-like peptide-1, GLP-1 (which slows down emptying to regulate nutrient absorption).²⁰ 

When gastric emptying is too fast or too slow, it can lead to issues like nutrient malabsorption, bloating, or discomfort. Understanding and maintaining this delicate balance is vital for overall digestive health​.

How to support this step: Consider what’s on your plate 

The rate of gastric emptying is essential for optimal digestion and nutrient absorption. When emptying is slow and controlled, it can enhance digestion, regulate energy levels, and increase feelings of fullness. On the other hand, when food leaves the stomach too quickly—a phenomenon called “dumping”—the small intestine can become overwhelmed, impairing its ability to process nutrients effectively.²¹ 

The foods you eat impact the speed of this essential process. Consuming meals high in simple sugars or fats can create an osmotic effect, pulling water into the small intestine and accelerating gastric emptying.

On the other hand, including dietary fiber and protein in your meals can help slow things down.²¹ Fiber provides bulk and delays the stomach’s emptying, while protein can activate gut peptide hormones like cholecystokinin (CCK), which signal the stomach to slow its roll.²² These mechanisms ensure a more gradual release of nutrients into the small intestine, supporting digestive health and prolonged satiety​.

The Winding Road Through the Intestines

By the time food exits the stomach, it is still only partially digested. The small intestine, measuring about 22 feet long, takes center stage in the next phase of digestion. Despite its name, the “small” intestine is a highly specialized, narrow, and coiled tube where most digestion and nutrient absorption occurs. It is divided into three regions: the duodenum, jejunum, and ileum.²³

The small intestine is lined with tiny, finger-like projections called villi, and even smaller structures called microvilli. Together, these create a vast surface area for maximum nutrient absorption. Enzymes and bile secreted into the duodenum break down carbohydrates, proteins, and fats into their simplest forms: glucose, amino acids, and fatty acids, respectively. These nutrients are absorbed into the bloodstream or lymphatic system and transported to the liver, where they are processed and distributed to meet the body’s needs.²³

What remains after this rigorous extraction process—undigested fibers, fluid, and shed cells from the digestive tract—moves into the large intestine, also known as the colon. This is where most of your gut microbiota resides, forming a complex and dynamic ecosystem.

Trillions of bacteria, from more than 500 species, call the colon home.^24,25 Many bacteria specialize in fermenting indigestible carbohydrates, like those found in fiber-rich foods, producing short-chain fatty acids (SCFAs) that provide energy for colon cells and other health benefits. Other bacteria assist in breaking down substances such as lactose or generate enzymes to digest otherwise inaccessible nutrients.²⁵

Gut microbes also influence intestinal motility by producing metabolites and neurotransmitters that regulate peristalsis—the rhythmic contractions that move waste along.²⁶ Additionally, they assist in water reabsorption, transforming the remnants of digestion from liquid into the more solid form we recognize as stool.²⁷ Despite this dehydration, about 75% of stool is still water by the time it touches down in your toilet bowl!²⁸

The large intestine’s microbial activity doesn’t just aid digestion—it also impacts hormone production. Certain bacteria play a role in producing key appetite-regulating hormones such as GLP-1, PYY, and ghrelin, which indirectly support nutrient absorption and metabolic balance.⁶

By the time waste completes its journey through the colon, it is compacted and ready for the final step in the digestive process: elimination.

How to support this step: Prioritize probiotics

Science-backed probiotics like DS-01® Daily Synbiotic target the intestines and the trillions of bacteria residing in the colon, working to optimize digestion.  

Each dose of DS-01® packs a whopping 53.6 billion live bacteria; roughly equivalent to the yearly acorn yield of 24.4 million oak trees.²⁹ The bacterial strains chosen for DS-01® are able to support the intestinal barrier and improve multiple markers of healthy digestion such as regularity, ease of expulsion, gas, and bloating.* With a proprietary capsule-in-capsule technology, DS-01® is engineered to survive digestion, so the enclosed probiotics make it to the colon alive, where they can get right to work. 

EXPLORE FURTHER: Probiotics 101

Final Destination: Down the Drain 

When the rectum at the end of the large intestine fills up with stool, it signals to the brain that the time for evacuation has come. Cue: the urge to visit the porcelain throne.

When you’re ready to go number two, the muscles that close off your anus open.^28,30 What was once a tasty meal exits your body and drops into the toilet bowl, marking curtain call on an exciting journey. All in all, this whole gut transit time usually lasts anywhere from 10 to 73 hours—a digestive drama that begins anew every time you eat.³¹ 

How to support this step: Put your feet up

Your position on the toilet plays a surprising role in this final evacuation. 

This is due to your anorectal angle—the angle between your rectum and your anus. If you’re in a seated position on a typical American toilet, this angle is around 100 degrees, which can be a little tight for stool to pass through comfortably.³² 

When you switch into a squat position, with your feet elevated and torso tinged slightly forward, this angle gets closer to 126 degrees, allowing stool to pass more freely.³² Just think about how much faster you can drive on a straight highway compared to a winding road. With no twists and turns, you’re bound to pick up some speed. In fact, squatting while pooping has been shown to accelerate the passage of bowel movements by roughly a minute.³³ 

Using a Defecation Posture Modification Device (DPMD)—the fancy scientific name for a toilet stool—can make achieving this posture less of a hassle. One 2019 study found that using one can reduce straining and the amount of time spent on the toilet while increasing bowel emptiness, leading to pride-worthy poops.³⁴

The Key Insight

Digestion is a complex and deeply collaborative process, with many organs, muscles, and bodily juices coming together to get the job done. 

Once this journey comes to an end, it’s worth reflecting on. And that means looking before you flush. Your number twos—and their shape, consistency, odor, and color—can tell you a lot about your gut health, immune function, and metabolic status. Now sure how to read this vital health metric? Allow us to help decode your next defecation.