Yes, your baby is probably taking in enough. It may seem like his whole meal is coming back up, but it's likely less than a tablespoon, so don't "top off" your baby with more milk if he spits up after eating. In fact, overfeeding can lead to even more reflux. Your pediatrician will evaluate your infant's weight gain at his well-baby checkups. If everything's on track, that means he's getting the calories he needs.
But if your baby refuses to eat to begin with, reflux may be the culprit. It's possible that the stomach acids flowing back up the esophagus are causing it to redden and swell. An irritated esophagus hurts, and it can discourage some infants from eating. So talk to your pediatrician if your child seems to have a poor appetite. He might diagnose your baby with gastroesophageal reflux disease (GERD) -- a more serious condition, in which your baby isn't gaining weight, refuses to eat, suffers from forceful projectile vomiting or develops respiratory problems from aspirating food. The condition can't be cured, but it can be treated with anti-reflux meds. --Rachel Morris
Originally published in Parents magazine, February 2008. Updated 2009