You should attempt to achieve a reasonably balanced diet. You should strive to maintain a high protein intake to prevent muscle loss. So a 150 lb adolescent or adult needs about 54 grams of protein per day. This requirement can be as much as doubled if the individual is in intense athletic training. These protein requirements should be met regardless of how much you are decreasing your daily caloric intake.
Vitamin deficiency is common on low calorie diets so a daily multivitamin is also recommended.
FAT content of low calorie diets is usually low. However, zero fat or extremely fat deficient diets should be avoided because they can result in essential fatty acid deficiency. To do this 3 to 4 small meals spaced evenly over the day will avoid prolonged fasting. Limit your carbohydrate intake, especially sugar. Allow yourself large quantities of low calorie beverages which will distend your stomach, giving you a sense of fullness, without the calories.