There is truth in this - I actually beat back my candida in a similar way - with tons of greens and some meat.
There is a simple explanation as to how this actually works. The greens provide fiber, mainly in the form of cellulose, inulins and FOS that feed the beneficial flora in the intestines. The flora ferment these fibers to produce acids that turn off the Candida growth gene and keep the Candida in a benign yeast form. Alkalinity of the intestinal tract and other areas where Candida resides turns on the Candida growth gene and converts the Candida in to its aggressive fungal form as studies have shown:
These beneficial acids also help prevent the overgrowth of pathogenic bacteria among other benefits:
I used candex for awhile and also found it to have good results, but went with nystatin (something my kid could take too).
I have addressed Candex previously as well:
One other thing. Some people mistake the passing of undigested cellulose for Candida and even parasites. Don't fall for this mistake. Have things checked by people who know what they are looking at and have the proper tools, such as microscopes to properly identify these things.