I have systemic candida and LGS. They took biopsies and ran test for gluten allergies. Everything came back normal, despite the fact that I had lost over 100lbs. in 3-4 months. Now I have gained all that weight back and then some. And as far as "doctors" go, most doctors don't know crap about candida, LGS, parasites, etc. Trust me, I've seen about 30 of them and most of them either laugh at me when I tell them I have these things or looked at me confused, because they have never heard of candida, LGS or a person living in a non-third world country having parasites.
The best way to determine if you have candida is the symptoms. If you are a woman, do you have frequent yeast infections, infertility, itching, etc.? Is your tongue whitish when you look at it, especially in the morning? And your friends are right. Chronic sinus infections are a sure sign of candida. If you have just a few problem, then lucky you, you probably have a minor case and can get rid of it much easier than the rest of us, who have serious cases of it. Try the diet for a month and see how you feel on it. Get an anti-fungal and take it at the same time. If you feel better, i.e. more energy, sinuses better, etc., then you have answered your question. You can find extensive lists of candida symptoms on the net. I would look into parasites
as well. Parasitic infections can cause many if not all the symptoms as candida and they often go hand in hand with them. Again, I speak from first hand experience.