Caloric Intake

So just how many calories should should an athletic teen consume a day? Everyone is different in their own way (age, gender, weight, height) so their isn't a set amount of calories that a person needs a day. To figure out a nutrition plan, first you have to find out how many calories you burn a day. This is called your total daily energy expenditure (TDEE) or your maintenance level. The average maintenance level for women is 2000-2100 calories a day, while men have a maintenance level of 2700-2900 calories a day. However, as mentioned earlier, depending on who your are and what you do, your body may require more or less than the average. Triathletes may require 6000 calories a day just to maintain body weight.

BMR (Basal Metabolic Rate)
To calculate your maintenance level as accurately as possible, you calculate your BMR, or the amount of calories needed for bodily functions and physical activity. This requires you to use several factors in the equation, such as height, weight, and gender. A higher BMR means that your body has high metabolism- your body can get rid of the stuff you put into it quickly. It is said that the more muscle you have, the higher your BMR can possibly be.

Formulas Based on BMR-

Harris-Benedict Formula (based on total body weight):
     Men: BMR= 66 + (13.7 x weight in kg.) + (5 x height in cm.) - (6.8 x age in years)
     Women: BMR= 655 + (9.6 X wt in kg) + (1.8 X ht in cm) – (4.7 X age in years)

Katch-McArdle Formula (based on lean body mass):
     BMR (men and women) = 370 + (21.6 X lean mass in kg) 


You can use these formulas to figure out what you should consume each day.

Sources:
http://healthrecipes.com/calories.htm


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