Couple Questions

I have a dehydrator it doesn't have a fan I cant find the other one with the fan they work so much better, anyways my oven is a breand new convection oven can I use it for dehydrating I can set it at say 90 and it will stay at 90 I think it will be more efficiant. Also I was on yahoo raw food group and they say our body dont use condiments and will store them like the cayanne I used on the Master-Cleanse so don't eat chilis,Also they say garlic is poison and onions are not good either ,is this true ???? This is my third day raw and I don't want to get confused.
Nora