Digestion and metabolism
Every bite of food has a roughly six-meter-long journey ahead of it – starting in the mouth and ending in the anus. Everything from meat to vegetables to bread will be digested by juices and acids, and broken down into their various components. Useful substances will go into the blood, be filtered through the liver and then travel around the body in the bloodstream. A network of hormones regulates what happens with the nutrients. All of this usually happens without us noticing it: we generally only become aware of our digestion and metabolism when they no longer work as they should.