My first instict is to say "no, it wont stall her" as long as she's not eatting too few, or too many calories, and she'seatting enough veggies,drinking enough water, no hidden carbs (from protein bars, and other "low carb" foods)...etc.

I have one or two protein shakes (scoop designer whey chocolate protein powder, a little cream, water) a day, and it's never stalled me, but I'm also very active so I don't know if that has anything to do with it.

I wish I could give you a definite answer, but everyone's body reacts differently. The only way she'll know if its going to stall her is basically to try and see what happens.

Hope that helped a little, and I didn't confuse you even more

Good luck,

-Michelle