I worried once, but when ds#1 (born 4.64kg/10lb4) weighed 6kg at 5wo (now 8kg at 3mo) I knew that he could get plenty in 5-6, 5min feeds every 24 hours. such a change from my 1 hour feeder in ds#1, who also ended up a big boy, but with him I thought I over fed him as he took so long & got so fat... now decided I just have fat building milk