PKU Sphere20, Banana, 35g Sachet. 120 calories per sachet. Powdered medical food for the dietary management of Phenylketonuria. PKU sphere is Vitaflo’s first glycomacropeptide (GMP) based medical food and has a GMP-dominant protein source supplemented with amino acids, bringing patients the potential benefits of GMP without any compromise in nutritional profile. Suitable from 6 years of age.