i think it depends on your activity level. some diets go as low as 1200, but that's risky...you can start to make your metabolism think you're starving. i got this from about.com: Q: How do I know how many calories I should consume? A: To determine your approximate caloric needs, you can easily compute your basal metabolic rate. This is the number of calories your body needs to maintain its basic functions and your current weight. You can determine your BMR by multiplying your current weight by 10. For example, if you weigh 180 pounds, then eating 1,800 calories a day would be your BMR. However, this computation doesn't take into account exercise or your activity level. For example, since someone who exercises regularly can bring in more calories and still be at their maintenance weight, their BMR would be higher. Other issues like genetics, age and the amount of body fat/muscle you have can also affect your caloric needs. and this from another website underneath the BMR method: If all of those calculations seem too confusing or tedious, you can roughly estimate your daily calorie requirements using this simple formula: For sedentary people: Weight x 14 = estimated cal/day For moderately active people: Weight x 17 = estimated cal/day For active people: Weight x 20 = estimated cal/day Note: Moderately Active is defined as 3-4 aerobic sessions per week. Active is defined as 5-7 aerobic sessions per week. that's how much you need to eat to maintain...i think you subtract 500 calories to lose.