Our metabolism is the total amount of energy our body uses to keep us alive and get us through the day. This includes energy used to maintain ‘hidden’ bodily functions such as breathing, circulating blood and growing and repairing cells.
Our metabolism is made up of:
- Resting metabolic rate (RMR); this includes energy used for basic functions such as breathing and keeping our heart beating. This accounts for 60-75% of our metabolism.
- The thermic effect of food; the energy used to eat, digest and process food. This accounts for 5-15% of our metabolism.
- Planned and incidental physical activity account for the rest of the energy or calories your body uses and is by far the most variable factor. This can include energy used when walking, gardening, vacuuming, playing sport or any other movement.
Factors that can affect your metabolism include:
- Body size and composition- The larger you are or the more muscle you have, the more calories you burn (even at rest).
- Gender- Men tend to naturally build more muscle than women and therefore tend to have faster metabolisms.
- Age- Unfortunately as we get older, our muscle mass declines and fat often accounts for more of our weight, which slows down calorie burning.
- Genetics- Some of us are lucky enough to be born with faster metabolisms, however we can’t blame genes entirely for a slow metabolism.
- Some medical conditions- A small percentage of people have a medical condition (such as hypothyroidism or Cushing’s syndrome) causing a slower metabolism, however this alone cannot be blamed for excessive weight gain.
- Some medications can affect the way our body utilises fuels or stores body fat(such as steroids and insulin)
While our metabolism does play a role in our weight, a slow metabolism is rarely the cause of excess weight gain. The bottom line is that weight loss comes down to energy balance. In order to lose weight, you need to burn more calories than what you put into your body through the foods and drinks you consume, therefore diet and physical activity ultimately determine our weight in most cases.
Reducing your energy intake moderately, eating regular balanced meals (including breakfast) and exercising regularly can aid with sustainable weight loss. Including a combination of strength-based exercises and aerobic exercise in your regular routine can help you burn more calories and aid with building and maintaining muscle mass to increase your metabolism. So ditch the crash diets and get moving!