Metabolism
Metabolism refers to the biochemical processes that convert fuel (calories) from food into energy needed to keep you going. Even during sleep, your body is constantly burning calories.
What are the role of hormones in metabolism?
Insulin helps our bodies to store nutrients from food, whereas hormones such as growth hormones and adrenaline help to mobilise these when the need arises. Thyroid hormones control the rate of metabolism.
What is my basal metabolic rate, or BMR?
Your BMR is the rate at which your body burns up calories to maintain its basic bodily functions. Even if you stayed in bed all day, your body would still burn up calories.
Your BMR makes up approximately 60% of the energy you use in day. It decreases as you age, due to a reduced muscle mass and an increased fat mass.
How does eating impact my metabolism?
You also use energy to digest, absorb and store away nutrients from food. This is called the "thermic effect" of food, and it accounts for about 10% of your daily energy expenditure.
What about the times I'm active?
Making up the rest of energy expenditure is the energy burned when you’re up and about. This is known as the "non-resting energy usage". This is the most variable component, which can be significantly increased by engaging in regular physical activity.
Is there a magic formula?
There is no magic formula. The more active you are, the more energy you will use up. With age, your body composition changes (more fat, less muscle), reducing your ability to burn energy. To fight back, do regular exercise and stay physically active. It can increase your BMR and improve your health and fitness.
To maintain your weight, no need to obsessively count your calories or to stop enjoying food: Just check that your calorie input doesn’t perpetually exceed your calorie output.
It may help to memorise this easy rhyme: “A minute on your lips, forever on your hips!”
Daily energy needs (calorie chart)
Check out the chart below to gauge the daily calories you need, based on your activity level.
| |
Activity Level |
| |
Light |
Moderate |
Heavy |
|
18 to <30 years old |
160 |
54 |
2000 |
2100 |
2350 |
|
30 to <60 years old |
160 |
54 |
2050 |
2150 |
2350 |
|
60 years old |
160 |
54 |
1800 |
1900 |
2100 |
Defining your activity level:
- Light: 75% of the time sitting or standing, and 25% of the time moving around.
- Moderate: 25% of the time sitting or standing, and 75% of the time doing some light physical work.
- Heavy: 40% of the time sitting or standing, and 60% of the time doing heavy physical work.
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