Many people are now realising that the intensity of an exercise determines what sort of energy stores are burned as fuel in the body. The body uses carbohydrates, fat or proteins as sources of energy during exercise.
So which fuel is used, and when?
During exercise, the body requires glycogen to provide the working muscles with energy. One of the three fuel stores mentioned above provides this glycogen. It is exercise intensity, not the type of exercise, which determines if fat is being used as the fuel source. Exercise intensity is measured by how much oxygen you are using. In low intensity exercises (less than 40% maximal oxygen usage) the principle source of fuel for the body is fat. Beyond 40%, this becomes carbohydrate.
How do I burn lots of fat?
At these lower intensities of exercise, less actual fat is burned (because you are doing less exercise!). So what you need to do is increase the intensity slightly to 50% of your maximum (so that slightly more carbohydrates are being burned than fat), but because of the higher rate of exercise, more grams of fat will be burned overall!
So 50% of your maximum effort is your best rate to drop those kilos.
How do I work out what is my maximum effort?
A good way to approximate this is to use your heart rate. Your maximum heart rate (beats per minute- BPM) can be approximated by the following: 220-age (years). For example, Jenny is a 30 year old female, and her maximum heart rate would be approximately 190BPM. So for Jenny to burn fat and drop lots of kilos, she should do exercises that keep her heart rate around 95BPM.
What are good exercises for this?
Great exercises for this are high-paced walking, moderate swimming, spinning or cycling (in low gears to ensure lots of pedalling!) or even activities like tennis or netball should help. The longer you can keep your heart rate at 50% of your maximum, the more fat you will burn and the kilos will simply fall off.








it is so good to have it set out simply like that. I wonder how many peopel think they are doing the right thing by running and getting completely out of breath tolose weight when in actual fact it is wuite the opposite. Thanks for a great article