Won’t eat

My 19 month old won’t eat anything, I’ve tried different varieties of foods but she won’t eat none of it. She will eat fruit one day but the next day she’s not interested. I’m getting really concerned, what are some suggestions to getting her to eat more? Should I try pediasure? Or does anyone have any recipes to homemade smoothies I can make for her just so she can have those nutrients.? Please help!