19 month old baby won't eat
Other than asking your doctor, I like the suggestion of making sure your child is getting a good whole food vitamin and perhaps try smoothies (yogurt mixed with fruits and veggies) as they are easily digested and get vitamins and minerals into the blood stream faster than actual food.
I've never had any issues with my babies not eating. They loved to eat. I think I would question if they are getting too much to drink (juice or other drinks) or possibly too many snacks that may be hindering their appetite.