K.D.
My oldest daughter has a metabolic disorder called SCAD, which is similar to MCAD. Has the pediatrician suggested cornstarch to help keep her blood glucose up? Is she on Carnitine supplements? Even if she could go longer without eating, you prob would not sleep since you would be worrying about her! It will get better, my daughter is now a healthy 16 yr old. I would try to find some support groups of parents that are going through similar challenges, good luck and blessings!