My little one has always spit up a lot but it hasn't been as bad lately. He smiles now when he does it so I don't think it is reflex. Anyways, I ate A LOT of pizza last night and he spit up A LOT this morning after nursing. I don't eat a lot of dairy. In fact, I was vegan until I was craving dairy during my pregnancy. I know I've read that dairy can stay in your system for a long time but I'm wondering how soon your lo can be effected by it if they have an allergy? Could he have already been reacting this morning to something I ate last night? If he is allergic to dairy now will he always be?