This will help her kidneys: Since she is elderly, if you are feeding any high-protein food, like alfalfa leaves or soy products, you should stop feeding it. It will take a load off her kidneys. Iguanas are genetically programmed to eat lots of low-nutrient plant matter. Hind gut fermentation turns the fiber into carbs. In the wild they also eat flowers and figs when they are in season, but don't need them as part of their staple diet.