SLC2A1 and GLUT1 deficiency syndrome: Such an example related to our topic here is the treatment of the rare disease glucose transporter 1 (GLUT1) deficiency syndrome using KDs: despite only “low level” evidence available, a recent consensus guideline recommends KDs as the treatment of choice for GLUT1 deficiency syndrome mainly based on the physiological mechanisms that ketone bodies are able to cross the blood-brain barrier independent from GLUT1, providing an alternative fuel for the brain instead of glucose [84].