Metabolism
Key facts
- Metabolism is the processes where your body converts what you eat and drink into energy.
- When your body has more energy than it needs your body stores the excess energy as fat.
- There is little evidence to show that special foods or supplements can increase your metabolism.
What is metabolism?
Metabolism is the processes where your body converts what you eat and drink into energy.
The food and drink that you eat contains:
Your body breaks these down into simpler forms. These are then converted into energy by your body. Your body uses this energy to help carry out everyday functions.
How is metabolism measured?
Kilojoules measure the amount of energy your body uses.
Many people are familiar with the term calorie. A calorie is another measurement of energy. One kilocalorie = 4.18 kilojoules.
How does my metabolism work?
Your metabolism involves two processes, catabolism, and anabolism. These two processes are carefully balanced to help you stay healthy:
- Catabolism is the process of breaking down food into simpler forms, releasing energy.
- Anabolism is the process of using this energy to build and repair cells in your body.
Sometimes, your body has more energy than it needs. When this happens, your body will store the excess energy as fat.
What affects my metabolism?
Different factors affect your metabolism. These factors include your:
- body size and composition
- sex
- age
- genes
These factors dictate how much energy your body needs.
Larger people burn more kilojoules, even when resting. This includes people with more muscle.
Males usually burn more kilojoules than females of the same age and weight. This is partly because males have more muscle.
As you get older, you lose muscle, which slows your metabolism.
Genes also play a role in muscle size and growth, which can affect your metabolism.
These factors together make up your basal metabolism. That is the amount of energy your body needs to survive, and includes basic body functions like:
- growing and repairing your cells
- using your brain
- pumping blood around your body
- moving your muscles
- keeping your body temperature constant
- making hormones and enzymes
- breaking down food
Being active also affects how your rate of metabolism. This includes regular exercise as well as regular tasks, such as:
- work
- housework
- socialising
How does my health affect my metabolism?
Health issues can affect your metabolism. Hyperthyroidism can increase your metabolism and cause sudden weight loss. Hypothyroidism can disrupt your metabolism and lead to weight gain and obesity.
Your metabolism can also affect your health. It appears that people have different metabolic rates, which can influence their weight. Being overweight or underweight can, in turn, affect your health.
Can I increase my metabolism?
Everyone has a different metabolism. This is because your basal metabolic rate and physical activity varies.
Many people try to boost their metabolism to burn more kilojoules and lose weight. There is little scientific evidence to show that any special foods or supplements can ‘boost’ your metabolism.
Although it's hard to change your metabolism, the more physical activity you do, the more kilojoules (energy) you use.
Some ways to burn kilojoules include:
- aerobic activity such as walking, cycling and swimming
- strength training
- moving around more each day
Strength training can increase your metabolism by increasing your muscle mass.
By practicing healthy eating, you can influence the amount of energy your body is taking in. You can do this by eating a balanced diet.
Resources and support
If you are concerned about your health or your metabolism, you should see your doctor or call healthdirect on 1800 022 222 (known as NURSE-ON-CALL in Victoria). A registered nurse is available to speak to, 24 hours, 7 days a week.
Learn more here about the development and quality assurance of healthdirect content.
Last reviewed: September 2022
