My 2nd son was 33 lbs, more than 4x his birth weight at 1 year. Now, at 7 years, he weighs a healthy 53 lbs., only 20 lbs more than at 1 yr!!
Lots of people including our pedi expressed polite concern about his largess.
I have always said that you cannot force a baby to breastfeed. They have to want/need it.