We all know that to lose weight, we need to burn more calories than we consume. In fact, our bodies have been designed to be very good at burning calories. It’s just that western society has been very creative in finding effective ways to overcome the efficient way we were designed to burn calories, e.g.
Tasty and convenient processed food and quick and easy fast food
Big designer dinner plates that need more food on so they look right
Comfy sofas that must never be left while the TV is on
Reliable cars that take us everywhere (to work, the town centre, the corner shop at the end of our road…)
It's our metabolism that burns calories and it does it in three ways: through digesting food, our general day to day activities and our basal metabolic rate (BMR).
If we increase our metabolism, we burn more calories. There’s not a huge difference we can make to the first two ways. The thermic effect of digesting our food is pretty constant at 15%. Our active daily living also burns around 15% of our calories a day. This is obviously dependent upon how active we are in our daily lives but it will always be a relatively small percentage of our calories burned.
This leaves our BMR responsible for a whopping 70% of calories burned each day!
Now any small change to our BMR will have a considerable effect on the total calories we burn, e.g. slow it down a little, less calories are burned. However if we can increase it a little, this will greatly increase how many calories we burn each day.
So the obvious question is “how can we increase our BMR?”
Lean muscle mass and cardiovascular fitness (CV) account for 80% of our BMR. Therefore by increasing both our lean muscle mass and cardiovascular fitness, we can increase our BMR a little, which in turn increases the rate significantly at which our metabolism burns calories and hence help us lose weight.
Lean muscle mass is increased through resistance training and requires more energy to maintain that muscle, therefore burning more calories 24 hours a day.
Increased CV fitness through CV training also improves the rate at which we burn calories. However, the majority of people will go to the gym and spend 20, 30, 40 minutes or more on a treadmill, bike, cross-trainer etc. and wonder why they are not losing weight. This type of continuous, or steady, CV training is really only maintaining rather than increasing fitness.
To make a difference to our BMR, we need to increase the intensity of our CV training by incorporating interval training.
Interval training involves high intensity exercise for short duration periods, typically 30 – 60 seconds followed by low intensity exercise, e.g. 60 seconds recovery, repeated several times, typically 3 – 4 times.
As well as burning calories during the exercise, CV interval training also continues to burn calories after we have completed the exercise.
Interval training also increases fitness, whereas continuous CV training does not (as we have said, it only really maintains fitness). This means that it is CV interval training that increases our BMR.
From this we can see that to lose weight, we need to increase our metabolism and high intensity exercise will go a long way to achieving that through increasing our BMR by increasing the intensity of our exercise program.
The other element to weight loss is nutrition but that will be discussed another time.