Well, there are glycogen storage diseases and deficiencies in fat and ketone metabolism that can make glucose essential. The sort of universal glucose requirement that Paul Jaminet pushes doesn't seem to have much to support it though.

When somebody does better with a Perfect Health or other moderate carb approach vs. Atkins or something more ketogenic, it's hard to say that the carbohydrate is what made the difference. Even if the additional carbohydrate comes from something like white rice, there's a lot of nutrition coming along for the ride along with the carbohydrate. I guess a study with pure white sugar or starch might help prove if there's such a thing as a glucose deficiency (in a more common sense).