For the most part, curing Psoriasis means discovering what foods you can and cannot eat. I've done it for myself, and I have only a about five spots left. Basically, everytime I eliminated a food I suspected was intolerable by my body, it proved true, and more spots disappeared. It's pretty cool!
I'm an advocate of the notion that there's not a single Psoriasis diet. Rather, each of us has a unique case, and each of us needs to discover his or her own diet so in a sense, for as many cases of Psoriasis that exist, there are equally many psoriasis diets.
To give an example, I have read many diets which say psoriasis people should not eat citrus. In my case, this is not true. I tested lemon and lime and noticed no adverse reactions. Then when I added grapefruit in, some of my spots rapidly disappeared. It seems I tolerate grapefruit really well.
I've always "loved" grapefruit. I recommend you do an almost "trance-like" analysis of foods you like or don't like. Let your body tell you. Then try sticking just with those foods for awhile, and see if your spots lessen.