What type of polysaccharide is the main source of fiber in our diet?

My guess was cellulose. Is this correct?

Yes, your guess is correct! Cellulose is indeed the main type of polysaccharide that serves as a significant source of dietary fiber in our diet. Cellulose is a complex carbohydrate made up of long chains of glucose molecules attached together. It is a structural component of the cell walls of plants. While humans lack the enzymes necessary to break down the bonds in cellulose, it still plays an essential role in our diet as insoluble fiber. This means that it passes through our digestive system largely intact, adding bulk to the stool and aiding in bowel regularity. Consuming an adequate amount of dietary fiber, including cellulose, has several health benefits, such as maintaining bowel health, reducing the risk of constipation and diverticulosis, and promoting overall digestive health.