Contrary to popular belief, refined carbohydrate intake doesn’t increase the risk of developing IC, and most yeast found in stool is likely derived from food and saliva.[1][2]
Unlike the microbiome, the mycobiome (i.e., the fungal microbiome, which includes Candida) is more closely associated with recent dietary patterns than with long-term habits. Although high-carb diets may produce short-term increases in Candida, they don’t seem to increase risk of IC, and low-carb diets (as well as low-yeast diets) don’t meaningfully affect the risk or severity of IC, either.[1][3][4]