Dr. Natasha Campbell-McBride compares human digestion with the digestion of grazing animals to explain why animal foods have a central place in GAPS. Her 2020 book emphasizes stomach acid, protein digestion and the work of gut microbes. It also explains why cooking and fermentation matter when plant foods are introduced.[1]
That comparison is easier to use when you picture the food you are actually preparing. Soft vegetables in a stock-based soup, raw salad and fresh vegetable juice are different forms of plant food. Understanding what changes between them helps make sense of the GAPS food sequence.
The Cow’s Rumen and the Human Colon
A cow is a ruminant. Its stomach has four compartments, and the rumen is the compartment where microbes ferment fibrous feed. That fermentation helps turn plant material into nutrients the animal can use. The cow also has an acid-digesting compartment, the abomasum, whose function is more like the human stomach.[2]
In the GAPS comparison, the important difference is where that large fermentation chamber sits. The cow’s rumen works near the beginning of digestion. Humans have one stomach, with the colon, or large intestine, farther along. Campbell-McBride compares the colon’s microbial work with the rumen’s work because gut microbes can turn some remaining carbohydrate into short-chain fatty acids, which the body can absorb.[4]
This helps explain why the book pays attention to the condition of the gut flora. Her argument is that the same plant material can feed a different microbial community in a disturbed gut. The location and activity of fermentation matter alongside the nutrients listed for a food.
How Humans Digest a Meal
Campbell-McBride places humans alongside predators and omnivores in her anatomical comparison. She emphasizes a single stomach, hydrochloric acid and pepsin, a protein-digesting enzyme, as part of her explanation for prioritizing meat, fish, eggs and suitable dairy.[1] Her earlier gut-flora chapter describes the stomach as much less populated by microbes than the colon, while still naming microbes that live there.[4]
The stomach is one part of digestion. Following a meal through the whole system makes the comparison clearer:
- Mouth: chewing breaks food into smaller pieces, and saliva begins starch digestion.
- Stomach: food mixes with acid and digestive enzymes, including enzymes that act on protein.
- Small intestine: pancreatic enzymes, bile and intestinal juices help complete digestion. Most nutrient absorption happens here.
- Large intestine: microbes help break down material that remains, and water is absorbed.[3]
GAPS uses the animal-food comparison to explain a nutritional priority. It does not require you to think of the stomach as the only place food is digested. The same vegetarianism chapter begins by describing humans as omnivores and gives both animal and plant foods a role.[1] My meat and fish guide connects that nutritional discussion with actual food choices.
Why Preparation Matters on GAPS
The book describes fermentation, malting, sprouting and cooking as traditional ways of preparing plants to make their nourishment more accessible. That is a broad food-history discussion. A preparation method being named does not make every grain, seed or plant suitable for GAPS.[1]
For your own meals, keep the ingredient and its preparation together. A carrot cooked until soft in soup is different from raw carrot or carrot juice. The food name alone does not tell you which form fits your current GAPS instructions.
| Preparation | Its Place in the GAPS Explanation |
|---|---|
| Cooking | The book favors cooked plants when digestion is sensitive and describes them as gentler than raw forms. |
| Fermentation | Campbell-McBride describes fermentation as another way to make plant matter more digestible. The food and introduction guidance still matter. |
| Fresh juice | The book uses juice to provide plant substances while removing most of the fiber. Juice has its own introduction point; it does not replace the animal foods in the diet. |
| Raw plants | The More-Plant chapter says bloating, crampy pain or abnormal stool after raw vegetables, nuts or fruit means waiting with those forms and focusing on cooked plants.[1][5] |
Use the GAPS food list and the instructions for your current approach when choosing ingredients. Cooking an excluded food does not introduce it into the GAPS list.
Keep the Foods and the Approach Together
The comparison does not give everyone the same animal-to-plant ratio. Campbell-McBride describes animal foods as largely building and feeding foods and plants as largely cleansing foods. She argues that animal protein and fat are better suited to building human tissues than their plant counterparts, comparing the amino acids in those proteins and the fatty acids in those fats. She also says those roles overlap: cooked and fermented plants can provide nourishment, and animal foods can have a cleansing role.[1] The cleansing-and-building guide explains that part of her framework.
No-Plant GAPS and More-Plant GAPS have distinct purposes and instructions. More-Plant keeps animal foods in the overall pattern while allowing different proportions and some vegetarian meals. Its chapter directs people with diarrhea, particularly with blood or mucus, or abdominal pain to Intro first.[5] The vegetarian-eating guide keeps the book’s broader vegetarian discussion separate from the named GAPS approaches.
Use This in Your Kitchen
Choose one familiar meal and look at three things: its animal foods, its plant foods and the preparation of each. Include the stock and cooking fat. A vegetable-heavy soup made with meat stock still contains an animal-food base, even if there are no pieces of meat in the bowl.
Then check whether those ingredients are introduced in that form. This gives you a useful next cooking decision: keep a tolerated cooked vegetable, choose a permitted protein, or look up a food before changing its preparation. You do not need to settle every question about long-term food proportions before making the next suitable meal.
My Stock Pot Course is listed in the WFLI Shop for help with the stock-based cooking that supports these meals. If you are deciding how to begin GAPS, the Intro-versus-Full comparison explains those starting options.
Frequently Asked Questions
Does the Comparison Mean Humans Cannot Digest Starch?
No. Human starch digestion begins in the mouth and continues farther along the digestive tract.[3] The GAPS restrictions concern particular foods and the digestive condition being addressed. They are not the same statement as saying the human body has no way to digest carbohydrate.
Does Having One Stomach Mean Everyone Needs No-Plant GAPS?
No. The 2020 book recognizes different individual proportions and gives More-Plant its own place. Use the actual dietary-approach guidance, including its digestive-readiness conditions, rather than choosing a more restrictive diet from the animal comparison alone.[1][5]
References
- Campbell-McBride, Natasha. Gut and Physiology Syndrome (2020), “Vegetarianism,” the digestive-anatomy comparison, plant preparation, food roles and individual proportions.
- University of Wisconsin–Madison Division of Extension. The Overview of the Digestive System of the Calves, the four stomach compartments, rumen fermentation and acid digestion.
- National Institute of Diabetes and Digestive and Kidney Diseases. Your Digestive System and How It Works, digestive organs, starch and protein digestion, bile and nutrient absorption.
- Campbell-McBride, Natasha. Gut and Physiology Syndrome (2020), “Gut Flora,” stomach microbes, the colon and the comparison with rumen fermentation.
- Campbell-McBride, Natasha. Gut and Physiology Syndrome (2020), “The More-Plant GAPS Diet,” cooked and raw food forms, digestive-readiness conditions and continued animal foods.
Leave a comment