Until recently my 2 yr old son was a good eat...

Until recently my 2 yr old son was a good eater, but for the last couple of weeks he' been chewing his food then spitting it out.which is making me sick i'm nearly 7 months pregnant. This happens with all food, fruit, pasta, meat. It's driving me up the wall, wasting all this food. the only thing that he hasn't spat out yet is yogurt and banana's. he occasionally eats properly when i feed him.