There are two basic metabolic processes – one is constructive, and is responsible for building and storing energy for the body. The other is destructive, though in a positive sense, as it breaks down nutrient molecules to release energy.
The constructive metabolic process is called anabolism, while the destructive process is called catabolism.
Anabolism promotes the growth of new cells, the maintenance and repair of tissues, and the storage of energy – usually through body fat – for future use. Small nutrient molecules are converted into larger molecules of protein, carbohydrates and fat.
Catabolism, meanwhile, is responsible for immediately providing the body energy to use. Instead of building up, it breaks down the nutrient molecules to release energy.
These two processes do not occur simultaneously but are balanced by the body.
Catabolism, in particular – though some attribute this to overall metabolism – has three components:
1. Basal metabolism – Sometimes called resting metabolism, this is the metabolism component responsible for keeping you alive by ensuring normal body functions. Even if you were bedridden the whole day, basal metabolism is still at work.
Basal metabolism is metabolism’s main component, as 60 to 70 percent of the calories from the food you eat are used for this. People who want to lose weight usually aim for a higher basal metabolic rate (BMR).
2. Physical movement - This can range from a simple moving of your fingers to strenuous exercise. Usually 25 percent of the calories you consume go here.
3. Thermic effect of food - This indicates the digestion and processing of the food you take in. Normally, ten percent of the calories of the food you eat are burned through this.
Find out more about what affects metabolism…