Why is fiber not absorbed?

Fiber is not absorbed because it consists of complex carbohydrates that the human digestive system cannot break down. Unlike simple sugars and starches, which are digested and absorbed in the intestines, fiber passes through the gastrointestinal tract largely intact. Its primary roles include promoting healthy digestion, regulating blood sugar levels, and supporting gut health by providing bulk to stool and fostering beneficial gut bacteria. This non-absorbable nature of fiber is essential for maintaining overall digestive health.