Final answer:
Soluble fiber increases the viscosity of intestinal contents, slowing digestion and potentially reducing hunger, whereas gastric inhibitory peptide slows digestion of fatty foods by reducing peristaltic movements and acid production in the small intestine. Insoluble fiber aids in bowel movement but does not affect the viscosity of intestinal contents.
Step-by-step explanation:
Soluble fiber increases the viscosity of intestinal content, slowing digestion which may decrease hunger. This nondigestible complex plant carbohydrate dissolves in water, forming a gel-like substance that thickens and slows the movement of chyme through the small intestine. It also slows the absorption of glucose into the blood, potentially lessening insulin spikes and reducing the risk of type 2 diabetes. Sources of soluble fiber include foods like oats, apples, and beans.
Another factor affecting digestion is the gastric inhibitory peptide, a hormone secreted by the small intestine in the presence of fatty acids and sugars. It works to inhibit acid production and peristalsis, thus slowing down the rate at which food enters the small intestine and allowing for more extended digestion of fatty foods.
Insoluble fiber, on the other hand, does not dissolve in water and provides bulk, stimulating peristalsis in the digestive tract. This type of fiber is classified as a carbohydrate but is also a nonessential nutrient, as our body cannot produce it, so it must be obtained through our diet.