Various types of potatoes. A staple food, or simply a staple, is a food that is eaten routinely and in such quantities that it constitutes a dominant portion of a standard diet for a given people, supplying a large fraction of energy needs and generally forming a significant proportion of the intake of other nutrients as well.
Constipation is defined medically as fewer than three stools per week and severe constipation as less than one stool per week. Constipation usually is caused by the slow movement of stool through the colon.
Bleeding that takes place in the esophagus, stomach, or the first part of the small intestine most often causes the stool to appear black or tarry. Your doctor may use the term melena.. Bleeding in the upper part of the GI tract will most often cause black stools due to: Abnormal blood vessels.