The actual amount of energy consumed per day is a simple formula:
Daily Energy needed = “Amount your body needs” + “Amount you body needs to do extra things”
The amount your body needs is the total amount of energy required for your heart to pump, your lungs to fill with air, your body to keep warm,
your hair to grow, your stomach to digest food and all those things you generally don’t think about in a day.
This is known as the basal metabolic rate. This is what your body would need regardless of what activities you do. Generally speaking the larger
you are the higher your basal metabolic rate. Think about it: a 100 pound woman needs less energy to breath and pump her heart than a 300 pound man.
This is no different than the amount of fuel a Mazda Miata needs to drive around town compared with an army tank.
The basal metabolic rate is usually pretty static, that is to say, it doesn’t change. If your body needs 1,000 calories of energy a day for your basal rate
then it will need the same amount tomorrow and the day after that. It is also important to note that everybody’s basal metabolic rate is different.
The amount your body needs to do extra things is the total amount of energy your body needs to lift heavy objects, or type on your computer
or walk to the store, etc. This is all the stuff that you don’t need to do just to keep alive, but you choose to do for whatever reason.
Let’s consider this to be the amount of work you do in a day.
So we can now write our formula can like this:
Daily Energy needed = Basal Rate + Work