weight, food, age

Question
Hi my name is David. My Fiance and I have a 6 month old pure breed yellow Labrador Retriever named Max. He is a beautiful puppy. He already weighs 65 pounds and he is about 23" tall. He still looks like a puppy. He has not gotten his adult face yet, he still has massive paws, very floppy ears. We currently feed him Iams "Puppy Large Breed" dog food and we go by the feeding chat on the back of the bag(total of 5 cups-2 cups morning, 1 and a half at noon and 5 O'clock) I was wondering how long I should keep him on this puppy food and when I should switch to Adult food. I was also wondering if "Iams" was a good brand; we use this kind because it is what his parents ate. My last question is how big do you think he will get. His mother was 88 lbs. full grown and his father was 85 lbs full grown. The breeder told me he is already larger than both his parents were at 6 months and she said he may grow be 100 pounds. In the 4 months we've had him he has been growing about 12 pounds a months. (I was wondering when he was going to slow down.)

Answer
Likely it is as good as anything.  I would switch to the adult version of the Iams now.  Likely you have been feeding him to much of too rich of a diet.  Large breed dogs that are overweight also are more prone to developing hip dysplasia. Obesity is especially dangerous for young puppies, as their underdeveloped frame cannot support the extra poundage that it must carry.  He may already have much of his adult size.  

Your dog definitely should be narrower at the waist than the hips and chest.
You should be able to easily feel the ribs, but not see them.  Each dog is
different.  Standard recommendations are a good place to start, but each dog
must have its food adjusted to its individual needs. Here is a link to a good illustrated guide,
http://www.longliveyourdog.com/twoplus/RateYourDog.aspx