Hi Lisee
No you are not thick!
Will try to explain briefly and simply...
Essentially the GI Diet principles are that if you eat foods with a low gi (a low number) it makes it easier for your body to lose weight. However some foods have a low gi but are still high in fat and calories - so common sense should still apply here! Don't eat them!
If you just want to eat healthy (not diet) you can eat in the main low gi foods and occasionally medium GI foods.
I think that food with a GI of 1-50 are low, 50-70 are medium and 70-100 high. But I am not 100% sure so if you are interested check out some websites and books.
I throughly recommend the GI Diet book by Rick Gallop I have lost 2 stone and four pounds since september following it.
Luv CC xx x xx x