To understand the usual cause of such conditions as constipation, diverticulosis, inflamed bowel and other intestinal symptoms, it helps to imagine a portion of food that we've just eaten. Once in the stomach, this portion of food is referred to as the "bolus."
The bolus must pass through a long and convoluted intestinal system, almost 30 feet in a typical human. How easily it does so depends on how moist the bolus is, how much water it contains. That in turn depends upon how much fiber the bolus contains, since fiber absorbs water.
It's an interesting fact that virtually all foods from the plant kingdom (unless they've been highly processed) contain fiber. Equally interesting is that no food from the animal kingdom contains fiber. That is, corn, carrots, apples, potatoes, etc. all contain fiber, while eggs, dairy, meat, fish and poultry all contain none.
When a bolus that contains little fiber moves through the intestinal system, it gradually loses moisture, dries up and becomes hard. Thus its passage through the intestines becomes more and more difficult, which can result in inflamation, constipation, irritation, the formation of intestinal pockets and so on.
Conversely, when a bolus that contains lots of fiber passes through the intestines, it retains water and softness and thus continues to move through easily.
This is one of the primary arguments for eating a vegan (plant-based) diet: It is far more constructive for our entire intestinal system.
Experiments have been done in which supplemental fiber was added to high animal-food diets. However, the effects were nowhere near as good as a vegetarian or vegan diet that contains lots of natural fiber to begin with. Such experiments strongly support the notion of eating a vegetarian or vegan diet.
Bear in mind that intestinal problems can be very serious. Consequently, it is always wisdom to consult a health professional who can be aware of your personal situation.
ójim sloman, summer 2000 for Jun 11