Hills prescription diet canine rd canned is a complete food that is formulated for overweight and obese dogs it contains l carnitine to help burn fat while increasing lean muscle mass it is also low in calories and high in dietary fibre to ensure that your pet feels full and satisfied as well as antioxidants that maintain a strong and healthy immune system weight gain is the result of an increase in body fat and is usually caused by eating too much especially when combined with a lack of ex