How much energy does my body need?
Your body's energy requirements vary depending on age and sex.

For infants and children there is no difference in the energy requirements in males and females up to the age of 11 years old.

Newborn
The newborn needs 110 calories for each kilogram of body weight. For example, if your newborn weighs 3 kilograms he need 330 calories a day. Your 1 month old baby who weighs 4 kilos (8 1/2 lbs) needs 440 calories a day.

Children 1 - 3 Years
Children from 1 - 3 years need about 100 calories for each kilogram of body weight.

Children 4 - 6 Years
Children up to 4 years of age need 90 calories for each kilogram of body weight. If your child is 1 year old and his weight is 9 kilograms (20 lbs) and his height is 71 centimeters (28 inches) he will need 100 calories per kilogram of body weight, or 900 calories a day.

A child who weighs 20 kilograms (44 lbs) will need 1,800 calories a day.

Teenagers
This is the age group where most concern is about when it comes to controlling weight. The news is that if your teenager finishes his teenager years it as overweight, it is most likely that he or she will continue to be overweight for the rest of their life. This is the time to increase the awareness.

From Teenagers to Adults:

Females:
A teenage girl 11 - 18 years old needs 2,200 calories a day.
An adult female needs 2,200 calories a day.

Males:
An 11 - 14 year old boy needs 2,500 calories a day.
A 15 - 19 year old young man needs 3,000 calories a day.
An adult male needs 2,300 calories a day.

You Will Notice 2 Things
The general trend is that the older the person gets, the less calories he needs for each kilogram of body weight. You can see this in the following charts, one for females and one for males:

FEMALES

900 calories a day

1,000 calories a day

2,200 calories a day

2,200 calories a day

MALES

900 calories a day

1,000 calories a day

3,000 calories a day

2,300 calories a day