The cells of your body are fueled by glucose molecules that travel throughout your body in the bloodstream. Because glucose is so important, your body responds to fluctuations in blood glucose levels to maintain stable levels through homeostasis. After consuming food, the mouth and stomach begin the process of mechanical and chemical digestion. The partially-digested food moves from the stomach to the small intestine where larger molecules are further broken down. Smaller molecules, like the monosaccharide glucose and fructose are absorbed by the cells lining the intestine.