wieviel ballaststoffe hat eine banane — what are common causes?

A medium banana (about 100–120 g) contains roughly 2.6–3.1 g of dietary fiber, mainly pectin and resistant starch (in unripe bananas). The amount varies with ripeness and variety. Common causes of low fiber intake include a highly processed diet lacking whole grains, fruits, and vegetables, as well as excessive consumption of refined carbohydrates. The provided context does not contain specific information about bananas or fiber; this answer is based on general nutritional knowledge.