Normally, our bodies run on energy from glucose, which we get from food. We can’t store large amounts of glucose, however. We only have about a 24-hour supply. When a child has no food for 24 hours — which is the way the diet begins, usually in a hospital — he or she uses up all the stored glucose. With no more glucose to provide energy, the child’s body begins to burn stored fat.
The ketogenic diet keeps this process going. It forces the child’s body to burn fat round the clock by keeping calories low and making fat products the primary food that the child is getting. In fact, the diet gets most (80 percent) of its calories from fat. The rest comes from carbohydrates and protein. Each meal has about four times as much fat as protein or carbohydrate. The amounts of food and liquid at each meal have to be carefully worked out and weighed for each person.
Doctors don’t know precisely why a diet that mimics starvation by burning fat for energy should prevent seizures, although this is being studied. Nor do they know why the same diet works for some children and not for others.
Trying to put a child on the diet without medical guidance puts a child at risk of serious consequences. Every step of the ketogenic diet process must be managed by an experienced treatment team, usually based at a specialized medical center.