It is a privilege and an honour to deliver this, the Turner Gibson Oration for 1989. I chose the title of my lecture because glucose, as the essential substrate for brain function, is indeed the fuel for our thoughts. Although important at all ages, it has a particular significanice for the young child, since a normal supply of glucose is essential to protect brain development and hence the potential for thought in the child's brain. Thus, glucose should have a high priority in our own thinking as paediatricians. With this in mind, the purpose of my lecture is to fuel your own thoughts on your management of children who have disordered glucose homeostasis by examining controversy, challenging current dogma and providing new information. Copyright © 1991, Wiley Blackwell. All rights reserved