Dr says I need to try a GI diet HELP

my dr has told me to go for low-gi foods as part of treatment for me Chronic Fatigue
he didn't give me much information, and a lot of the sites i've looked at are about loosing weight which I don't want to do (will make me more ill) so I'm struggling to find some information
can anyone help?

Daughter one of mine used that. She was hardly fat...weighed 10 stone and 5 8" but she got that book and has lost 10 pounds. She looks great on it too. Dead healthy, shiny hair and eats lots each day. Drfinately a lifestyle thing, more than a quick burst i would say.