For a very physically active person:
18 calories per pound of desireable body weight
For a person with normal activity level:
15 calories per pound of desireable body weight
For a person with light activity level:
13 calories per pound of desireable body weight
From our previous pages, we know that our average frame 5ft 5in woman has an ideal weight of 125 pounds and we'll assume her doctor has agreed. (you should not assume. Do check with your doctor before undertaking any weight loss or gain program).
Given her normal activity level, to attain or maintain 125 pounds, she needs to consume about 15 calories times 125 pounds or 1875 calories per day.
If she is a very physically active person, she could consume 2250 calories per day. (18 calories tiimes 125 pounds).
You now know your ideal weight, height, frame size, activity level and given these, an approximate number of calories you are to consume daily to maintain your ideal weight.
Each pound of fat that you lose or gain is equal to about 3500 calories. So when you eat 3500 calories less than you should you lose a pound and when you eat 3500 calories more than you should you gain a pound.