On occasion, some babies may have intolerance to certain foods. This is more common in babies born into families who have existing food allergies. If you are breastfeeding a baby who has sensitivities, he may exhibit slight or extreme symptoms ranging from fussiness and spitting up, to eczema and diaper rash.
If you feel your baby has a sensitivity to foods you are eating, there are ways you can try to determine the culprit. Try to cut out a specific food group, such as dairy, and watch how your baby responds. It will likely take at least four or five days to see a difference because you’ll need to wait until the food group has completely cleared your body. It actually takes dairy two full weeks to clear the system. You can try this for each of the food groups and then start slowly adding each group back one-at-a-time to see how your baby reacts.