5 month old Lab feeding

Question
Hi.  I have a 5 month old yellow lab and she weighs 31 pounds.  I'm currently feeding her Purina ProPlan Puppy food, 3 cups a day over 3 meals.  Does this sound right?  She is very active, and very slim, and she begs for her evening meal up to an hour before she normally gets it.  Do you think I should be feeding her more?  I understand that labs will act like they're starving no matter how much food you give them, but I worry that I'm not feeding her enough!

Answer
I once took a Lab to the zoo.  At the seal display, it dawned on me why Labs eat the way they do.  When my dog started barking back, I quickly moved on.  You can cut back to 2 meals a day now, and one after 6 months if you want to.  I would make my next bag the adult Pro Plan.  An early switch to adult food slows growth allowing more time to develop sturdy joints for a long, active life.  

Your puppy is eating half again what my 5 month old Lab is, but could need it.  To better judge her body condition, see http://www.puppychow.com/products/popup_body_condition.aspx  If you need to, adjust her food or exercise.  Won't hurt to have the vet comfirm your judgement next visit.  

I feed Holly her second meal at 6 PM and give our old dog a snack.  They spend most of the time after 4 PM staring at me.  Evey time I even start toward the bathroom where the food is, they come running.