How many calories should I eat?

Thanks for the tremendous support thus far everyone. Please be sure to follow me! Some of the questions I got yesterday revolved around how I figured out the number of calories to eat. As we know caloric intake depends on many things: our gender, height, current weight, and physical activity. There are tons of ways of calculating your caloric intake but what I used was the Harris-Benedict equation, which happens to be the most popular. This involved a three step process.

What this means to you!

Before you dive into calculating your calories, let me just remind you that the Harris-Benedict equation or any equation that estimates your calorie needs is just that, an estimate. These are based on averages and will give you a good starting point, but you need to see how your body reacts and adjust accordingly. To loose 1-2 pound per week, it's usually recommended to subtract 500-1000 calories from your total caloric needs. You need to have a 3500-calorie weekly deficit to loose 1 pound of fat. But for some this may be too aggressive at first and cause you too loose sight of your long term goals. If you are currently weight training, doing HIIT cardio and eat a healthy diet, you may just want to start with a 250 calorie cut. Remember that this is a marathon not a sprint :)

Calculating your calories

Step 1: Calculate your lean body mass

To calculate your lean body mass, all you need to do is take your current weight minus your body fat. If you don't know your current body fat percentage, you can use this calculator. This will give you an approximate number. Also if you belong to a gym, the majority of them will measure you for free!
Lean Body Mass = weight - (BF%*weight)

Step 2: Calculate your Basal Metabolic Rate (BMR)

Just plug in your weight, height, and age below. The output will be the estimated caloric intake you need in order to maintain body weight. If you don't feel like working out this formula, you can get a pretty decent calculator here for women and a great one here for men.
For women:
English 
BMR = 655 + (4.35 x weight in pounds) + (4.7 x height in inches) - (4.7 x age in years)
Metric
BMR = 655 + (9.6 x weight in kilos) + (1.8 x height in cm) - (4.7 x age in years)
For men:
English
BMR = 66 + (6.23 x weight in pounds) + (12.7 x height in inches) - (6.8 x age in year)
Metric
BMR = 66 + (13.7 x weight in kilos) + (5 x height in cm) - (6.8 x age in years)

Step 3: Applying the Harris-Benedict Principle

This estimates how many calories you burn during your daily activities. To determine your daily caloric needs, multiply you BMR by your activity factor.

• Sedentary: Minimal movement, little to no excessive. Activity Factor = 1.2
• Light activity: Office work, plus light exercise 1-3 days/week. Activity Factor = 1.375
• Moderate activity: Light physical/manual labor during the day, plus moderate exercise 3-5 days/week. Activity Factor = 1.55
• Very Active: Light physical/manual labor during the day, plus hard exercise 5-6 days/week. Activity Factor = 1.725
• Extra Active: Active military, full time athlete, hard physical/manual labor job. Activity Factor = 1.9

Caloric Intake = BMR*Activity Factor

EXAMPLE

I'm sure all those equations have your head spinning ... so here is a quick example example where I just give you the output of the formulas. Let's take a 30 year old, 5'5" woman, who weighs 155 lbs, has 30% BF, and works in an office.

Lean body mass = 108.5lb
BMR =  1493.75
Activity Factor = 1.375
Caloric Needs =  2053.9

To loose weight you would subtract 500-1000 calories from this number, depending on the amount of weight you need to loose etc. So this woman would start my diet basics with 1500 calories.