Hello and welcome to the forum.
Cabbage will not feed the Candida, but it does feed the beneficial bacteria in the colon. During the process of digesting such foods as cabbage, gas is produced, and this is especially noticeable if the digestion is off balance – as is usually the case with Candida infestations. A product by the name of Grape Bitters can be purchased to aid digestion. Take half a dropper full of the liquid bitters instead of the recommended dosage. There are posts on the forum explaining this.
The diet as well as the Pau d’arco could be producing some die-off symptoms, this could explain the headaches.