At one time dog owners would readily give their pet dogs table leftovers, often straight from the table. However, these days, advice generally warns against this. This is not simply modern society gone mad but instead it is sound advice.
Too much salt.
Many foods made for human consumption contain far too much salt. Products such as gravy granules have so much salt that they could cause a dog, health problems. A dog's small kidneys would be unable to cope with this amount of salt and it would be bad for the animal's heart as well.
Sugar.
Dogs do not need sugar, especially in its refined state. The sugar that we consume is harmful to dogs in many ways. These days the incidence of Diabetes in dogs in increasing. This is mainly due to the sugar in their diet. What may seem like a treat to you could, in real terms, be poison to a dog.
Fats.
Similarly, rich fatty food is not good for a dog. It can increase a dog's weight and block its arteries in the much same way that a human's arteries become blocked. Such blockages can lead to heart failure. At the very least, these fats will lead to weight gain, which is not good for a dog. If the dog becomes obese, its life span will be shortened and it may suffer from poor mobility and muscle and joint health.
Excess protein.
Too much protein can make a dog hyperactive and restless.
Onions.
Onions can be very dangerous to a dog. Having said that this may not apply to all dogs. However, is it worth taking the risk?
Bones
When you feed you dog table scraps, the dog could easily ingest a bone. Small bones such as those in poultry, like chickens and turkeys, are harmful to dogs.
Digestive problems.
Many of the food manufactured for human consumption is just too rich for a dog. It will provide poor nutrition and may cause digestive problems. This could be diarrhoea, constipation, vomiting and more.
Behavioural problems.
Feeding your dog scraps and titbits from the table can cause bad behaviour. Your dog may become fussy and only eat certain foods. The dog may also pester you and your family as you eat.
Feeding your dog table scraps may also cause it to scavenge any old, discarded food that it comes across.
Milk
Do not give your dog milk to drink. This can cause tummy problems. Dogs like clean, fresh water.
Overall.
Be kind to your dog. In the long run tasty titbits from the table may cause problems and giving them to your dog is not an act of kindness.
Make sure that you NEVER give your dog chocolate, raisins, grapes or white bread, as all could cause severe health problems.
There are some foods that would not be harmful, but it is best not to start bad habits in the first place.
Feed your dog its own sensible diet in order to ensure it keeps in tiptop condition. After all, you would not eat left over tinned dog food, would you?