Calculating Caloric Needs:

Step 1. Estimate Your BMR:

Use the following formula:
370 + (21.6 X lean body mass in kg) or
370 + (9.8 X lean body mass in lbs)

If you weigh 200 pounds, and your approximate body fat is 10%, then you would have a lean mass of 180 lbs (200 - 10%). This gives us 2134 calories as our "BMR".

Step 2. Activity Factor:
Next, multiply the number you from step 1 by the following:

Sedentary (desk job, with little or no exercise) = BMR X 1.2
Lightly active (light exercise/sports 1-3 days/week) = BMR X 1.375
Moderately active (moderate exercise/sports 3-5 days/week) = BMR X 1.55
Very active (intensive exercise/sports 6-7 days/week) = BMR X 1.725
Extremely active (intensive daily exercise/sports & physical job or twice per day)= BMR X 1.9

So with the example above, and with exercise 6 times per week, we get 2134 X 1.725 = 3681

Step 3. Subtract 15%:
3681 - 15% = 3129 (3681 X .15 = 552 & 3681 - 552 = 3129)

You now have your starting calorie intake.

Now choose your goal either for weight loss or weight gain and either subtract or add the calories to your starting calorie number

Weight Loss -

Small weight loss, greatest preserver of muscle. About 0.7 lb lost per week subtract 350 calories

Moderate weight loss, good preserver of muscle. About 1 lb. lost per week. subtract 500 calories

Large weight loss, average preserver of muscle. About 1.6 lbs. lost per week. subtract 800 calories

Great weight loss, small preserver of muscle. About 2 lbs. lost per week subtract 1000


 Weight gain -

Small weight gain, least body fat gained. About 0.6 lb. gained per week. Add 300 calories

Moderate weight gain, small body fat gained. About 1 lb. gained per week. Add 500 calories

Large weight gain, moderate body fat gained. About 1.4 lbs. gained per week. Add 700 calories

Great weight gain, large body fat gained. About 1.8 lbs. gained per week. Add 900 calories

So for my example if I wanted to loss weight at 0.6lbs a week I would subtract 300 from 3129 and if I wanted to gain weight at 1.4lbs a week I would add 700 to 3129. - Simple really when you know how......