Metabolism is the set of life-sustaining chemical reactions in organisms. These reactions keep your body functioning by turning the food you eat into energy. Metabolism is a complex process, but it can be broken down into two main parts:

Breaking down food molecules (catabolism): This process starts in your mouth, where enzymes in your saliva begin to break down carbohydrates. The food is then further broken down in your stomach and intestines. The nutrients from the food are then absorbed into your bloodstream and transported to your cells.

Building up new molecules (anabolism): Your cells use the nutrients from food to build new molecules, such as proteins, carbohydrates, and fats. These molecules are used to repair tissues, build new cells, and store energy.