You should first of all identify what has caused your dog to be overweight. This is frequently due to your dog having been given an amount or mix of food that exceeds his individual energy requirements. Nevertheless, you should ask your vet whether your dog’s weight may be attributable to a hormonal disorder. If so, it is imperative that the causes of such a disorder are identified and appropriate treatment is prescribed.
If the cause of your dog being overweight is effectively the amount of food that he eats or insufficient exercise, it is essential that you take the necessary steps to rectify the problem: do not give him any unnecessary treats, or try a low-fat variety and reduce his daily food allowance by the corresponding number of calories. Check how much food you should be giving your dog and reduce the amount accordingly. If you prepare the food yourself, you should check that the mix is well balanced, substituting high-calorie food sources for low-calorie ones, without creating a diet for your dog that contains too much of any one nutrient or is low in nutrients.
Even if your dog urgently needs to have his weight brought down to a normal level, you should never put your dog on a starvation diet without consulting your vet, as this could cause your dog more harm. Instead, you should increase the amount of exercise that your dog receives. Even here, it is important that you start gradually and do not ask too much of your dog. Ask your vet or breeder how much exercise your dog can handle and seek advice on what kinds of sporting activity you might enjoy doing with your dog.