Feeding for a 4 Month yellow lab

Question
I just went to the vet today, and my four month old yellow lab weighs 30 pounds. The vet told me to to reduce his feedings to twice a day (I had been feeding him three times a day). However, I forgot to ask how much food I should give him each time. Also, when should I switch him to an adult food. Also, is Iams a good food? I've been reading a lot of negative articles about the food, and I just want to know if these articles are true.

Thanks!

Answer
Much of what you read about Iams and other common brands originates with premium brands' marketing hype.  Suppose you knew a breeder that bred hundreds of dogs a year, mostly Labs, Shepherds, and Goldens. They provided all the medical care for most of them the first year. At the end of it, they did a complete physical including hip X-rays on all of them. They then spent $35,000 training them before giving them away. They have a large data base of breeding records. Dogs with any physical or temperamental problems are unfit for the program and are a waste. Their well equipped clinic and vet staff are available for serious problems as long as the dog is working. When the dog is no longer able to work, it is replaced at again the $35,000 plus a large emotional upheaval for the person depending on the dog. They have experimented with different diets and exchanged data with other such breeders. Don't you think that what ever they are feeding is healthy and safe? How objective are the sources of your information? Is your dog's health, their top priority?

I have been raising puppies since 1991 for a large dog guide school that does exactly that. What do they feed? They instruct us to feed Pro Plan chicken and rice puppy chow until 4 months and then switch to adult Pro Plan chicken and rice. I know enough of the people with the trained dogs to know they continue the Pro Plan. The group I meet with monthly for training includes people that have raised puppies for 6 different service dog schools. Some of them are feeding other common commercial chows including Iams, science diet,  and Eukanuba. Any dog owner wanting a healthy, long lived dog can make this regimen work, leaving more time to spend on the dog. It is also relatively economical.

While the school we are raising our 17'th puppy for feeds Pro Plan, many other service dog schools feed Iams.  If you are feeding Iams, stick to it.  I know of many cases where somebody switched to a ''better'' food and had a mess.  At 4 months, I usually am feeding 1 1/2 cups each of 2 feedings a day.  That is also when I switch to adult food slowly over a week.  We ave raised puppies for another school and fed a couple of them Iam,s with good results.  Keep the dog lean.  

You should be feeding a puppy chow now. Switching to an adult chow for the larger breeds at 4 months, slows growth and helps develop sturdier joints.

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 and exercise adjusted to its individual needs. Here is a link to a good illustrated guide, http://www.longliveyourdog.com/twoplus/RateYourDog.aspx