Vet at FirstVet answers:
The most important thing to feed your dog is high quality dog food; it is required in order for your dog to get all of the important nutrients its body needs to function healthily. The rule of thumb is that a maximum of 10% of a dog’s diet can consist of feed other than its dog food.
Fruits and vegetables that are good for your dog include carrots, cabbage, apples, broccoli, etc. Many dogs like to gnaw on cabbage and carrots, which are rich in fibre and can help make your dog feel full. If you want to start giving your dog carrots it’s important to start with small amounts to see if your dog’s digestive tract can tolerate them. If so, gradually increase the amount given.
Fruits and vegetables that you should not give your dog include avocados, onions, garlic and grapes (raisins included!).