Many new moms have this same concern. When you can’t weigh your baby the best way to tell if he is getting enough to eat in the early days is counting bowel movements. A baby that is fed only breast milk should have about 4 poop diapers every 24 hours. Breastfed newborns feed about every one and a half to three hours. Feedings last about 30-40 minutes. When feedings last longer than 40 minutes or occur less than one hour apart, or you have any other reason to be concerned about your baby’s intake, contact your doctor immediately.