The formula I use is 1 scoop per 2 ounces. I use 3 scoops for 6 ounces of formula. Make sure you are reading your label correctly. If you are putting too much formula per ounce of water, that would be a real good reason for the high weight gain. I will tell you though that my baby at 7 weeks is already taking 6 ounces every 3 - 4 hours (except overnight, then it's 4 - 6 hours). He has almost doubled his weight from birth now I believe. He was born 7 lbs 4 oz, he was 10 lbs 15 oz at his one month check up. I too worry about mine getting too heavy and having issues later in his childhood, I think it's a common concern for us 'new mommies'. You say that he is 4 months old, 4 - 6 months is the typical time to start rice cereal. I'd place a call to your pediatrician and ask about starting it. 8 ounces every 2 hours is a lot and I believe that he will suggest giving some substance to at least a couple of feedings per day. Rice cereal has no nutritional value, just adds fullness for the belly. Good luck to you, I feel your struggle with feeding. It's scary to wonder "if you're doing it right".