My son was a "puker" too. I found he was wanting to drink more formula at 6months then he should really have (42oz a day!) So I switched him to a sippy cup, cut out the bottle and he slowed down to a healthy 26oz plus his baby food. I later found out the reason he puked so much was because he had a milk allergy and was gluten and soy intolerent.
He is now 4 years old and a healthy 38lbs
LOL he was 26lbs at 9months.