Is it true that formula fed babies sleep longer than breastfed babies?

It is unlikely that formula fed babies sleep longer than breastfed babies. This thinking probably came about because formula fed babies usually need fewer feedings in the day since formula takes a longer time to digest (formula contains more casein which takes longer to be digested, while breast milk has more whey that is easier to digest). However, like what Diana mentioned, night waking is not solely due to hunger. Therefore, a baby is still likely to wake up (especially at the end of each sleep cycle) at night regardless which type of milk he/she was given. If you have no intention of weaning your baby (and is only considering formula because of your baby’s night waking), it is probably best to continue with breastfeeding. It will minimize nipple confusion and also help keep your supply stable (one of my friends started having both formula and breast milk feedings and observed a drop in her supply).

Breastmilk is much more easily digested as compard to formula milk so a breastfed baby would feel hungrier faster. However, it may not be the reason that's waking them up in the middle of the night as the other mummies have mentioned. My son is formula fed and still wakes up in the middle of the night. Sometimes it's for milk, sometimes it's just to make sure I'm around and he would snuggle closer to me.

Your baby's night waking doesn't really associate with whether his tummy full or not. Some babies wake up at night to seek for comfort. If you suspect the night waking is due to hunger, you can tank up your baby during the day by nursing more frequent instead of introduce formula milk.

thanks