by CD Gozzi

Created on: July 27, 2007

So how many calories do I need? Well the first question to ask is, are you trying to lose weight or maintain your current weight? What is a calorie anyway? A calorie in scientific terms is the amount of heat needed to raise one kilogram of water one degree centigrade. Actually it should be referred to as kilocalorie but common vernacular keeps it as calorie. Okay so what does this have to do with food calories? Calories are the fuel our body burns in order to function. As our bodies burn the food, the chemical bonds break, liberating energy in the form of heat. The amount of heat given off is the energy availability, or how many "calories" it has.

So how many do I need? Depending upon your gender, age, physical make up, goals and activity level the answer may vary. You will want to determine your basal metabolic rate (BMR). This is the amount of energy your body needs just to function normally to live.
Women: BMR = 655 + (4.35 x weight in pounds) + (4.7 x height in inches) - (4.7 x age in years)
Men: BMR = 66 + (6.23 x weight in pounds) + (12.7 x height in inches) - (6.8 x age in year)

Your level of physical activity will also determine the amount of calories you need. A rough calculation for this is
Sedentary BMR x 20%
Lightly active BMR x 30%
Moderately active (exercise 4+ days per week) BMR x 40%
Very active (heavy exercise daily for a long period of time) BMR x 50%
Extremely active (have a job that is physically laborious or are an athlete in training) BMR x 60%

Add this to your BMR calculated previously. The last item to consider is the thermic effect of food. This is the number of calories your body consumes to digest and metabolize the food you have eaten. A rule of thumb for this is approximately ten percent of the daily caloric intake.

So now you will want to add all these together and see what your outcome is. If you are a 30 year old woman, fifty-four inches tall and weigh 150 pounds, your BMR is 1468. If she is moderately active this would add 587 calories to her BMR equaling 2055. If she eats approximately 1500 calories per day, her body would need approximately 150 calories to digest and metabolize the food. This woman's caloric need would be approximately 2205 calories per day.

One pound of fat in your body equals 3500 calories. If you want to lose weight, you will want to decrease your daily consumption of calories. If you cut back 500 calories per day, you will lose one pound in a week. You can both reduce the amount of food you take in as well as increase the amount of activity you perform.

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