How food is digested part 1

What happens to food after we place it in your mouth until it comes out the other end.

The journey food takes through our body is a very interesting, and also very complicated process. We eat because it is necessary to make sure we are getting the energy we need to stay alive, and that we get all the fuel, or materials required by our body for building and repairing tissue. This keeps us working every day to provide us with the energy we need to do what we need to do.

The energy and nutrients we used to stay alive are supplied in great quantities by the digestive system, or the gastrointestinal tract. The role of the digestive system is to breakdown to the food we eat into their tiniest parts so that they are absorbed easily across the gastrointestinal wall, and moved into our cells so they can do the roles they need to do. Digestion is both a physical and chemical process, where the digestive system uses its muscular structure to squeeze, shake, and bend the food to break it down, and produces different chemicals, such as enzymes, so that larger compounds, such as proteins, carbohydrates, and fats are broken down into smaller parts, such as amino acids, glucose, and lipids to be absorbed to fuel us.

Food can take between 12-24 hours to go from your mouth, all the way through, and be expelled on the other end looking very, very different from how it started. The digestive tract is about 9 metres from mouth to bum, and 6-7 metres of this is small intestine, which is where most nutrient absorption occurs!

When we put food in our mouth and start chewing, our teeth assist in breaking down the food so it is small enough to fit down the oesophagus and has already started the nutrient breakdown process, and the saliva moistens the food enough so that it can slide down into our stomach, and also helps start breaking down some nutrients. Chewing food thoroughly is an important part of ensuring the food is easily digested, and the tongue also plays a role in breaking food down and helping to push it down the throat.

Food enters the stomach, where very strong acid is added to assist breaking foods down for the nutrients to be absorbed in the next part of the digestive tract. The stomach contracts and expands (a bit like jumping up and down and moving from side to side) using its muscular wall to make sure all the food is mixed up and coated in acid, which helps with the further mechanical breakdown of food, so that when it passes on to the next part of your digestive system, the process of absorbing nutrients will occur easily. The stomach on average, takes 2 hours to empty after consuming a meal. Because the movements of the stomach require energy to work, that is why we can feel tired after eating a meal, especially a really large meal. From the stomach, the food is released past the end of the stomach into the start of the small intestine.

As the small intestine starts, there are a few other organs which help with the digestive process. The liver produces a chemical called bile, which assists to breakdown fat, which is stored in the gallbladder and added to the small intestine. The pancreas is an organ which is located up behind the stomach which produces compounds called enzymes, which assist with breaking down proteins, carbohydrates and some fats, and assist with changing the food – now called chime after being mixed with lots of compounds – from an acid state into an alkaline one to continue its journey through the digestive tract.


To continue the journey, check out our blog post next week to continue the journey of food.