How Digestion Actually Works

If you’ve had your gallbladder removed and you’re still experiencing symptoms, understanding exactly how digestion works — step by step — is the foundation for everything else. This page is that foundation.

Digestion Is a Relay Race, Not a Single Event

The digestive system is a long, continuous tube — roughly 30 feet from mouth to colon — and every section of it has a specific, non-negotiable job. What one section does or fails to do determines what the next section receives. The relay has to work in sequence. When it doesn’t, symptoms appear.

Here’s how the relay actually runs.

The Mouth: Where It Begins

Digestion starts before you swallow. Chewing breaks food into smaller pieces, and saliva begins the chemical breakdown of carbohydrates. This is also where the body starts sending signals downstream — what’s known as ‘the cephalic phase’ of digestion, a neurological response that begins preparing the stomach, pancreas, and gallbladder for what’s coming.

Most people don’t chew nearly enough. The downstream consequences of large, incompletely broken-down food particles are significant and often underestimated.

The Stomach: Protein’s Domain

The stomach is a large, muscular organ — and its size reflects its job. It’s a churning, acid-producing environment designed primarily to begin breaking down protein.

Stomach acid (hydrochloric acid) is extraordinarily potent — strong enough to denature proteins, kill most pathogens that enter with food, and activate the enzymes needed for further digestion. This process takes time. The stomach holds food for anywhere from 30 minutes to several hours depending on the composition of the meal.

Here is something most people don’t know: the stomach does not meaningfully digest fat. Fat passes through the stomach almost entirely intact. The stomach mixes it with the food it’s been processing and moves it along, but the chemical work of fat digestion hasn’t started yet. That happens next — and this is where the gallbladder does its important work.

The Duodenum: Nine Inches That Change Everything

When the stomach has done its work, it releases the bolus — the partially digested mass of food — through the pyloric valve into the duodenum. The duodenum is the first and shortest section of the small intestine, roughly nine inches long in an organ that stretches over 20 feet total. Those nine inches are arguably the most consequential in the entire digestive process.

This is where fat digestion finally begins. This is where bile arrives to do its job. And this is where the absence of a gallbladder creates the cascade of effects that so many post-surgical patients experience — often without ever being told why.

We’ll cover exactly what happens in the duodenum — and what bile is and what it actually does — in Part 2.

Why This Matters If You’ve Had Your Gallbladder Removed

Understanding this relay gives you a framework for understanding your symptoms. Each symptom has a location in the system, a mechanism behind it, and a reason it’s happening. That’s very different from being told “your labs are normal” and sent home.

The free guide below connects this framework directly to the most common post-surgical symptoms and what kinds of support actually address them.