Explain why eating high fiber foods can help prevent constipation?

Foods must be hydrolyzed (broken down) into simpler molecules in order for the body to be able to use them for energy and synthesis.

Enzymes are proteins which are organic catalysts. They speed up chemical reactions like hydrolysis which occurs when food is digested. One of the food groups consumed for energy is carbohydrates. These include sugar and starch. The body can break down these polymers into simple sugars called monosaccharides.

Cellulose, is also a...

Foods must be hydrolyzed (broken down) into simpler molecules in order for the body to be able to use them for energy and synthesis.

Enzymes are proteins which are organic catalysts. They speed up chemical reactions like hydrolysis which occurs when food is digested. One of the food groups consumed for energy is carbohydrates. These include sugar and starch. The body can break down these polymers into simple sugars called monosaccharides.

Cellulose, is also a polysaccharide and is the component of cell wall materials. Thus, when any plant based food is consumed, cellulose will be present.  It is a polymer of glucose molecules however, the glycosidic linkages (bonds) between glucose monomers consist of 1-4 linkages of beta glucose monomers. Celluose molecules are straight and unbranched.

Starch, a different polysaccharide, is composed of 1-4 linkages of alpha glucose monomers. While humans have enzymes that can break down the bonds in starch, we don't have enzymes that can break down the linkages in cellulose.

Cellulose in our food is known as fiber and passes through the digestive tract. However, it does stimulate peristalsis and helps to push out wastes from the large intestine. This can prevent constipation. Therefore, it is a valuable addition to the diet. 

I have included a link with a list of high-fiber foods that can be included in a healthy diet.