A lot of people are confused about how to calculate what your caloric intake should be.  I am no expert but this is the way I tell people to figure it out.

The first thing I want to say is:  NEVER GO BELOW 1200 CALORIES per day.  When a person does this, their body goes into starvation mode and attempts to hoard everything that is eaten.  This will result in weight gain and muscle loss.  This is not a good thing.

1 pound of fat equals 3500 calories.  So you must burn 3500 calories over and above what you take in over a weeks time to weigh 1 pound less.

Now to the calculations:

Take your weight and multiply it by 11.  This number is the amount of calories it takes your body to maintain its current weight.  Here is an example:  My weight at this time is 230.  230 X 11 = 2530.  So it takes me 2530 calories eaten to maintain my current weight of 230 pounds.

To lose one pound per week by only your caloric intake, you need to subtract 500 calories from your maintenance caloric intake.  Example:  2530 - 500 = 2030 calories eaten for me to lose 1 pound per week.

To lose 2 pounds per week, subtract 1000 calories from your maintenance caloric intake.  Example:  2530 - 1000 = 1530 calories eaten for me to lose 2 pounds per week.

I do not recommend anyone subtracting more than 1000 calories from their daily intake unless they are over 300 pounds.  I also do not suggest anyone under 200 pounds to subtract the 1000 calories. 

Your body needs calories as your fuel.  These are what your body burns in order to move.  At no time, do I suggest anyone to eat more than 3000 calories nor eat less than 1200 calories unless under a physician's supervision.

As for the type of calories you should bring in, my rule of thumb is:  40:40:20.  What this means is that 40% of your calories should come from carbs, 40% of your calories to come from protein and 20% from fat. 

Not all carbs are equal.  There are sugar carbs, simple carbs and complex carbs.  Please check out the authorized foods list for a list of these.  Sugar carbs will turn to fat unless used right away.  If you are going to eat something with sugar in it, natural or otherwise, they should be consumed about an hour after you do an intense workout.  This way, your muscles burn them as glycogen and it is not stored as fat.

Please read about why you should eat protein and carbs at every meal.  It will explain in more detail.

One gram of protein is 4 calories.  One gram of carbohydrates is 4 carbs.  One gram of fat is 9 calories.