It all depends upon how her body reacts to a higher fat and higher sodium consumption. There are 18 grams of fat in the two scoop serving that is recommended. In that two-scoop serving, you get 32 grams of protein, which I feel are necessary--especially if she is a natural competitor--200 mg of sodium, and 12 grams of carbohydrates, six of which are sugars.
I think you have to look at where your girl is at the eight-week mark. Is she right on track? Figure wants a softer, rounder look, and the excess fat and sodium might help with her maintaining a fullness to her body. You might then look at upping the cardio to keep the size of the muscles and the weight down.
Again, it all depends upon her body and her reactions to various food groups. I get softer and rounder when fat is added to the diet. I can watch it happen within a 24-hour period. On the other hand, my body works well with both simple and complex carbohydrates. So for me, the Muscle Milk is a huge no-no. For others, it works wonders.
Try taking it away from the diet for about three or four days and not changing any other variables. Watch her body closely to see what immediate changes you notice. Then you'll probably have your answer.