Royal canin veterinary diet gastro intestinal moderate calorie is a complete dry food that is tailored for cats that are overweight or have a tendency to gain weight easily while also offering relief from any gastrointestinal disorders problems with the digestive tract are a common complaint for cats as their stomachs and intestines are very sensitive the most common symptoms of a gastrointestinal disorder are vomiting and chronic diarrhoea in this case a long term change of diet is nec