This is what I was told by the breastfeeding consultant at WIC. She has over 25 years or more experience. The baby's stomach is as big as their own fist. Baby's do NOT need that much milk to keep them full. When I breastfeed my baby, he drinks what fills his stomach. When I give him the bottle, he will drink and drink and drink. He ends up with too much. In the beginning and just recently, we did a test at the WIC office. We weighed him before I fed him and after he finished (breastfeeding). The last time was when he was 4 1/2 months. He only had to take in 2 1/2 ounces and was full. So, from what I have been told by an expert, you can over feed a baby. They don't need much. Babies need about 3 hours of suckling a day. Milk comes out of the bottle much faster than a breast, so when they are on the bottle, they just keep trying to suckle and end up getting more than they need. The baby may end up spitting up more, upset stomach, cranky, hiccups, etc. I'm sure every person has been told different answers. This is just one more answer. Good luck.