There are very few controlled trials for those that try the anti-yeast diet with anti-fungals. Most naturopaths are seeing patients that are forced to stay on anti-yeast diets for years on end, 'the rest of their lives,' because the yeast issue is secondary.
The reason candida can suppress the immune response is that it is normally a symbiotic organism with humans. The European model on medicine, which has been very successful, has been to treat candida biologically. They understand that yeasts only become pathogenic when they are other infections causing diseased tissue, when there is heavy metals, and when the systemic tissue pH is imbalanced. (each tissue, of course, having its own optimum pH)
One can kill candida till the cows come home and never get to the real issue. This is a Western alleopathic approach to yeast. Chronic health problems are generally very, very resistant to alleopathic approaches.
There are many superior approaches to candida available than anti-fungals whether they be alleopathic Nystatin or more benign herbal approaches.
Pleomorphic sanum has a very good look at candida/fungal problems, as well as Dr. Bob Marshall, and also Paul Yanick.
Diet must still be addressed for everyone, of course. The various tissue pH's of the body can not become balanced unless diet is factored in. However, these diets can be far more easy than the tedious anti-yeast diets that are so commonly prescribed.