I go along with Lisa.

In the Aerobics and Fitness Association of America's "Fitness: Theory and Practice" book there is a chapter there covering nutrition and calories.

Chapter 24, page 202....
"A second step is to know how many calories/day are appropriate to eat. To roughly esitmate caloric needs for weight maintenance, multiply the DESIRED weight by 12-15 calories per pound for light to moderate activity; 15 -20 calories per pound for higher levels of activity. This number offers a very rough estimate of daily calorie needs; the actual requirements will vary greatly, depending upon individual metabolic differences.

From this estimate of calories needed to maintain weight, the third step is to determine the number of calories appropriate for weight reduction by subtracting 20 percent of the maintenance calories per day."

Now the above is assuming the person is light to heavily active in exercise.

I do know that the very bottom line anyone should consume daily is 1200 calories. Going below that will cause changes to your metabolism and not in a positive way.