Explore the Human Digestion Simulator
Build a meal, feed it through the digestive tract, and watch real enzymes break carbohydrates, protein. Free, no signup, runs in your browser.
- Free to use
- No signup
- Nothing to install
- Runs in your browser
Illustration. Open the tool for the real thing.
See it in action
The Human Digestion Simulator with sample data entered and the result showing.
What is the Human Digestion Simulator?
Build a meal, feed it through the digestive tract, and watch real enzymes break carbohydrates, protein and fat down while a graph tracks nutrient absorption over time. It runs in your browser, so a change to a setting or a drag on an object shows up at once.
Nutritionists design meals around exactly this timeline, and medical conditions like lactose intolerance or pancreatic insufficiency are explained by a missing step in this same pathway.
3 steps to your result
Open the tool and follow along. Nothing to install.
What you get
Carbohydrate digestion starts with salivary amylase in the mouth and finishes with pancreatic amylase in the small intestine, ending as glucose.
Protein digestion starts with pepsin and stomach acid, then pancreatic proteases in the small intestine, ending as amino acids.
Fat is emulsified by bile and broken down by lipase in the small intestine into fatty acids and glycerol.
Feed a high-fat meal and watch how long fat digestion takes compared to carbohydrate.
Slow down transit speed and see how much more gets absorbed before the small intestine ends.
Try the challenge: get over 90% of the carbohydrate absorbed before the meal reaches the large intestine.
Used for
Pick one to see how it fits.
Biology learners
Biology students and teachers who want to explore living systems, populations and genetics interactively and safely.
Try it freeTeachers
For teachers: project the Human Digestion Simulator on the board, let students predict the result, then run it together and test this: Slow down transit speed and see how much more gets absorbed before the small intestine ends. For students: change one thing at a time and write down what changes.
Try it freeHow it compares
A plain look at this tool next to the usual alternative.
| This simulation | Textbook diagram | |
|---|---|---|
| Interactive | Drag, tap and change settings | Fixed picture |
| Install | Nothing to install | Not needed |
| Cost | Free to use | Depends on the book |
Questions people ask
Why does protein digestion start in the stomach but carbohydrate digestion pauses there?
Stomach acid activates pepsin for protein digestion but also stops salivary amylase from working, so carbohydrate digestion resumes only once food reaches the small intestine.
What is bile's role in fat digestion?
Bile emulsifies fat into tiny droplets, giving lipase far more surface area to break it down efficiently.
Is the Human Digestion Simulator free to use?
Yes. The Human Digestion Simulator is free, needs no signup or download and runs in your web browser. It is part of the Biology group of AZRS simulations.
Does the Human Digestion Simulator work on a phone or tablet?
Yes. The Human Digestion Simulator takes touch input as well as mouse input, so you can use its 5 adjustable settings with a finger. A larger screen makes the controls and graphs easier to read.
How do I use the Human Digestion Simulator?
1. In the Human Digestion Simulator, use the controls to change Meal size, Carbohydrate share, Protein share, Fat share, Transit speed. The simulation reacts instantly. 2. In the Human Digestion Simulator, press "Feed the meal", "Check absorption", "Check fat absorption" to start, reset or change what is happening. 3. Start with this experiment: Feed a high-fat meal and watch how long fat digestion takes compared to carbohydrate. Drag any glowing handle, object or slider with your mouse or finger and the Human Digestion Simulator responds in real time. 4. Change one setting at a time and watch which readout moves, then compare it with this idea: Carbohydrate digestion starts with salivary amylase in the mouth and finishes with pancreatic amylase in the small intestine, ending as glucose.
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Try the Human Digestion Simulator now
Build a meal, feed it through the digestive tract, and watch real enzymes break. Free to use.
Try it free