By definition, metabolism includes all the cellular functions needed to maintain life. It is traditionally separated into two parts:
â€¢ Catabolism â€“ the breaking down of organic matter into energy.
â€¢ Anabolism â€“ The use of that energy to build up new structures.
When people use the terms â€œslow metabolismâ€ and â€œfast metabolismâ€ they are actually talking about â€œmetabolic rateâ€ which is the amount of energy (calories) our bodies use up to perform the functions throughout the day. Our caloric needs do not remain the same throughout our entire lives. Itâ€™s when our bodies begin to require less calories, that people say their metabolism has slowed.
This is an important concept to understand if you want to maintain a healthy weight because our body stores excess energy as fat when we consume more calories than we burn up. In a formula it would look like this:
Calories consumed â€“ calories burned = fat produced
If we eat more calories than we burn, our body will store up extra fat. If we burn more calories than we consume, our body breaks down fat.