I honestly think 900 calories is too few for anyone. 1200 calorie should be a minimum. If you're going to add around 500 calories though, might I suggest adding them as protein and fat? Furthermore, may I suggest altering your meals slightly such that you are not eating a quantity of carb and fat at the same time?
The rationale here is that when you eat carb in quantity, your insulin levels jump to try to shuttle away all that carb out of your bloodstream and into the tissues where it is used for energy. However, the body can only process one type of macronutrient at a time. Another function of insulin is to shuttle away the fat that you eat directly into your bodily fat stores, instead of to your liver to be processed into ketones, which are then used for energy. So just partitioning your carb and fat intake may provide an extra boost to fat loss — you won't be storing as much fat as you are burning.