sometimes their fur can become flaky, try adding oily fish such as tuna to the diet for a couple of days to see if this helps but be careful to take some of her normal portion out so your not overfeeding. if the white flakes appear to be moving it may be a mite called cheytiella "walking dandruff" which can be treated with advocate spot on treatment. moulting may be due to temperature changes or mites. check the food that your feeding, look at the guidelines to make sure you are not overfeeding for her weight, or change to a light diet or a high fibre diet. place the food in different areas of the house so she has to be active to get her food. monitor her weight monthly to ensure she does not continue to put on weight.
good luck.