Put basically we can think of our bodies as machines which we need to supply fuel to to make them run properly.
The amount of fuel is counted in terms of calories, which we consume in our food and then use up through the various funtions
(both conscious and sub-conscious) that our body is asked to perform. If we were to lie in bed in a totally sedantary state we would
need about 20 calories / kg that we weighed just to live - for our brains to function, bodies to keep warm, blood to keep pumping etc.
On top of this we need to provide calories for all the activities that we undertake, whether it be walking from the kitchen to the
living room or running a marathon. Clearly the number of calories that we need will be dependant on how much activity we do.
For an average person (whoever that may be!) the following calorie intakes are recommended
Men 2500 calories
Women 2000 calories
This would be for a person of average weight who does an average amount of exercise. As you are interested in running, it is likely
that you do more exercise than the normal person.
To help with this the following guide can be used (it is only approximate, but serves pretty well).
For each mile you run you will burn about 1.6 calories for each kg you weigh.
This means about 100 calories if you weigh 60kg or 130 calories if you are 80kg.
Surprisingly, this doesn't depend too much on
how fast you are moving, provided that you technique remains the same at all paces (for example if you lift your body up and down more
at a fast pace you'll use more energy). However, those who run faster clearly have time to do more miles and therefore use more
calories!!!