16 months - Vomiting

DS is 16 months, and he is at 90% for height, 75% for weight. He is happy & healthy. But for the past 2 months, DS has been vomitting (after dinner) about once a week. I don't understand what could be causing this, and I could really use some advice. Has anyone experienced this? Thanks!

My first instinct, if he is just spontaneously vomiting, is that it is a food allergy. My kids have food allergies, though none that trigger vomiting, but I have read about and know of kids who have this happen. Keep a food diary for a while to see if you find something that is common each meal. The other thing is that is it possible he is gagging himself? My youngest is 15 months now and just found out about his gag reflex. He hasn't vomited a meal yet but again, I have friends whose children have done this. Good luck