What's the worst advice or myth you've ever heard about breastfeeding?

"Breastmilk can't make baby to feel full because it is not thick enough as compared to formula milk." This is not true. Baby will unlatch or stop drinking once he/she feels full. A breastfed baby will never be overfed but a formula fed baby will. It is a norm that formula fed baby tends to be bigger in size. Also, formula milk's major ingredient is corn syrup which is very sweet and will cause obsesity.