She is 15 years old. Her digestion is delicate now , and the food that seems to agree with her best is Burns. She has this twice a day. If she even has a small amount of something different she gets " squeaky tummy" , and then wont eat anything for a day or two. Should I just increase this food to 3 times a day ? Or has anyone got any other suggestions ? Id be grateful for any advice. Thank you. She is soooo thin.