The best thing to eat after a tonsillectomy is cold soft things. Icecream with no nuts or anything in it and popcicles are always the first things to eat. You can eat jello, pudding and applesesauce. After a couple of days you might be able to eat chicken noodle soup very cooled. If you have had a tonsillectomy and are unsure on what to eat contact your doctor and they can provide a list of approved foods for you.