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.
In brief: Depends. Dark stools may be caused by digested blood from a stomach bleed. A test for fecal occult blood should answer this. Some foods like blueberries or meds like pepto-bismol can also darken stools. See your doc and share any symptoms you have so you can get a good workup. Dark stools may be caused by digested blood from a stomach bleed.