Digestion: the system underneath everything else
You do not benefit from what you eat. You benefit from what you absorb - and those are not the same thing.
Healthy World
Enzymes, bile and absorption - why digestion sits underneath every other kind of health.
You do not get the benefit of what you eat. You get the benefit of what you absorb. Those are different quantities and the gap between them is digestion.
It starts in the mouth, where saliva begins on starch, and continues in the stomach with acid and enzymes. Most of the real work happens in the small intestine, where the pancreas supplies enzymes and the liver supplies bile. Bile matters especially for fat - without it, fat passes through largely unused and the vitamins riding along with it go too. Then the large intestine, where bacteria work on what is left and water is reclaimed.
Fibre, which is what the large intestine runs on. Water, because fibre without it makes things worse. Regular meal timing, because digestion runs on a rhythm. Chewing, which is unglamorous, free and skipped by almost everybody. And a ten-minute walk after dinner, which does more than most things sold for the purpose.
Occasional indigestion is ordinary. Persistent pain, blood, unexplained weight loss, difficulty swallowing, or a change in bowel habit lasting more than a couple of weeks are not - those need a doctor rather than a dietary adjustment.
You do not benefit from what you eat. You benefit from what you absorb - and those are not the same thing.
Picked to go with what you have just read. We only list ordinary, widely available things.