Let’s explain this:
The largest component of stools is water — 65% to 85%. With low-fibre diets, undigested food remnants represent from 5% to 7% of total stool volume. With high-fibre diets, they represent 10% to 15%. That’s why healthy people who fast, or can’t eat solid food because of a sudden medical emergency, still continue to move their bowels — food, as they say, doesn’t make the weather.
This surprising disconnect between food and stools becomes self-evident after breaking down food staples into five basic components — water, carbohydrates, protein, fat, and fibre. Only fibre is indigestible. The rest are digested either completely or almost completely:
- Water from food and drinks is completely absorbed in the small and large intestine. Only about 100 ml (3 Oz) of “embedded” water is excreted along with normal stools, but this is proportionately more in a high-fibre diet. Water content in excess of 85% — just a 10% difference — is characteristic of diarrhea.
- Simple and complex carbohydrates (sugars and starches) digest completely in the small intestine (except lactose, which is fermented), and are absorbed into the blood as glucose, fructose, and galactose. More than 0.5% of undigested carbohydrates in the stools is considered abnormal.
- Protein from meat, fish, fowl, dairy, seafood and plants digests completely and is absorbed into blood as amino acids. So there’s no protein in normal stools, except burned meat.
- Close to 95% of all consumed fat is absorbed in the small intestine. Fat in stools in excess of 6% of consumed fat is considered abnormal. This condition is called steatorrhea.
- All food contains insoluble mineral salts and the earth’s minerals, which reach the large intestine undigested. This indigestible portion of food is called ash, and is determined by cremation. Normal stools contain from 0.2% to 1.2% of ash.
Thus, if your daily menu includes 200g of meats (2g of ash), 100 g of fat (5g undigested), and 200g of digestible carbohydrates (1g of ash), only 8 grams (one-and-a-half teaspoons) of undigested food residue will reach the large intestine. That’s not enough to even get noticed in the toilet bowl.
The feces are kneaded into stools by intestinal peristalsis, with a generous serving of mucus secreted by the intestinal mucous membrane. The mucus binds together food residue, intestinal bacteria, and metabolic debris — dead body cells and remnants of metabolic activity shed by the liver along with bile.
After all is said and done, normal stools contain around 75% water. In other words, if you consume a low-fibre diet, your body expels 25 grams of undigested organic and inorganic matter for each 100 grams of stools, and only eight of those grams come from food.
The water in formed stools is retained by dead cells and intestinal bacteria, which are also single-cell organisms. Bacteria reside on the surface of the mucous membranes. They divide and die in huge numbers round-the-clock. The dead siblings are shed into the lumen (colon’s cavity) and become an essential part of the stools. By some counts, dead bacteria represent up to 50% of dry stool matter, or almost 11 grams for each 100 grams of stools. (100g – 75g water – 5g fat) * 50% = 10 grams.
When bacteria are present, fibre has a moderate effect on the size and weight of stools because the bacteria ferment up to half of the insoluble fibre, while soluble fibre gets fermented completely. Thus, if your intestinal bacteria are alive and well, and you consume daily 20-30 grams of fibre from natural sources, it may add only 30 to 60 grams (the approximation of remaining unfermented fibre along with absorbed water) to the weight of your stools.
But if the intestinal bacteria are mostly dead (which is what causes constipation in the first place), and the dietary fibre remains unfermented, your stool weight will go up by 100-150 grams, because fibre attracts water up to five times its weight. The ensuing doubling of the stool’s weight and size — the bulking up, conventionally speaking, — will eventually cause the metamorphosis already described earlier.
People who consume fibre-rich diets excrete around 400 grams of stools daily. But that goes down to just 72 grams on a low-fibre diet, which is ideal! But with such a minuscule amount of normal stools, it’s paramount not to miss bowel movements. Otherwise small stools quickly dry out, become costive, and get difficult to pass out. Keep in mind that the drying out of stools happens regardless of the bacteria count — normal stools become dry when the moisture content drops as little as 10% down to 65%.
When bacteria are missing altogether, the stools are dry from the get-go. That’s why “fibre replacement therapy” works not just figuratively, but literally — fibre retains water in place of the missing bacteria, though it isn’t as efficient at keeping up the moisture as are bacterial cells. Remaining live bacteria keep devouring fibre and causing all of those prominent side effects of “rumination.”
There is only one reliable way to prevent the drying up of stools and ensuing constipation — move your bowels after each major meal, because the act of eating ALWAYS initiates the sequence of events that stimulate defecation. These successive unconscious events are called, respectively, the gastro colic reflex, peristaltic mass movement, and the defecation urge. That’s how our gut is wired by nature to move the bowels.
Unfortunately for most Westerners, once the potty training begins, the parents and teachers work really hard to unwire this miracle of nature. That’s so that you can finally leave the house without a diaper and sit through a class without interrupting it. It’s possible because the final stage of defecation doesn’t take place until you consciously permit it by relaxing your external anal sphincter.
As we grow up, we learn to suppress the defecation urge by constricting our rectums with our pelvic muscles. While still young, we squint, grimace, and cross our legs to accomplish it; later in life we can suppress all but the strongest urge, completely unnoticed and wrinkle-free.
But this essential social skill has a downside. If you keep suppressing defecation for too long, usually over a day, retained stools gradually impact, dry out, harden up, and require straining to get expelled regardless of size. When that happens, the chaffing of dry stools against the delicate lining of the anal canal causes all the problems described earlier
To summarize, you should move your bowels as soon as you sense the defecation urge, usually after each major meal. In this ideal situation, stools are soft, small, and barely formed, which is perfectly normal. They weight no more than 100-150 grams. If this optimal frequency isn’t attainable, you should pass stools at least daily, usually after breakfast. In this case, the stools accumulated over a 24-hour period are larger, heavier, and more formed, but still passable.