3. Overall caloric intake. For fat loss, aim for about 10-13 multiplied by your bodyweight. This gives you your daily caloric intake. For a 150-lb person, this is:
10 x 150 = 1500
13 x 150 = 1950
So, that means your daily intake of calories should be between 1500 and 1950 calories per day. Divide that by 5 or 6, and you have the total number of calories for each meal. Assuming we're eating the upper limit of 1950 calories daily, and we want to eat 6 meals, that means each meal should be around 325 calories. Now you're probably thinking, "No way! No way can I make a 300-calorie meal!" Well, think about this. A small skinless chicken breast, grilled, is around 150-200 calories. Throw that into a nice salad with a spoonful of olive oil vinaigrette and you have a very pleasant 300 calories. You get 6 of those a day! Pretty sweet deal.
By the way, maintenance calories (the calories needed to keep you in a steady state, neither gaining nor losing mass) are around 14-16 x bodyweight per day for an active woman. This will vary depending on the individual.
The caloric intake to gain mass is about 15-18 x bodyweight per day. Again, this varies depending on the individual. Activity is a big component of variation. The more active a woman is, the more she requires just to keep at the same weight. Age is also another significant component, as is fat-free body mass. In other words, a 200 lb. person with 10% body fat will likely not have the same caloric requirements as a 200 lb. person with 40% body fat. The second person can drop calories lower than the first person, without initiating an anti-starvation response. If the second person tries to lose bodyfat, she will also likely lose it faster than the first person.