Your body is designed to protect itself from starvation during times of greatly-reduced food availability. So when you eat too little, your body thinks it's starving. To compensate, your metabolism will slow down considerably, making it very difficult (or impossible) for you to lose weight. In this state, your body will preferentially burn everything but your stored body fat.
Eating too little poses other problems as well, such as nutritional deficiencies. On top of that, if you later increase your calories after a long bout of eating too few, your body will be more likely to store these calories as fat, in preparation for another future "famine."
Your best bet is to aim for a slow weight loss of 1-2 pounds per week by combining a moderate calorie reduction with increased calorie expenditure through exercise. If all the info you entered during your program set-up is accurate, the recommended calorie range you received should be what you need to accomplish this healthy rate of weight loss. www.sparkpeople.com/community/ask_the_expe