hat banane viele ballaststoffe — what are common causes?

The question whether bananas contain a lot of fiber can be answered clearly: bananas provide about 2.6 g fiber per 100 g – moderate, but not high. For comparison, oats (10 g) or legumes (7–15 g) contain much more. The Mediterranean fiber diet mentioned in the context emphasizes whole grains, legumes, nuts, and berries, not primarily bananas. The second part 'what are common causes?' is ambiguous. It might refer to common causes of low fiber intake: highly processed foods, low fruit/vegetable consumption, refined carbohydrates. Or it could refer to causes of digestive discomfort when suddenly increasing fiber (bloating, cramps). Since the provided context does not contain specific data on bananas or on 'common causes', the evidence base is weak. The Mediterranean fiber diet has strong human evidence for improving microbiome diversity, reducing inflammation, and improving metabolic markers, but bananas are only a minor component. For a personalized assessment, individual gut health, tolerance, and overall diet must be considered.