Dogs need the right amount of fat, protein, amino acids and vitamins. You could potentially cook all of this up yourself, but most owners go the route of buying 'complete' pet food from a pet-food manufacturer. This ensures that your pet-food is balanced with the right levels of nutrition. The disadvantage of purchasing prepared food is that they often contain preservatives which are artificial and have chemicals to provide color and flavor. It is also all pre-cooked which can rob it of some nutrients. The good thing is that they are so convenient and contain all the food that your dog needs for a balanced diet.
You can choose from dry mixes or moist tinned varieties. There are also sachets and organic ready-made foods. There also specific foods available for senior dogs and puppies. This is great as their requirements for food do differ at these key stages in the dog's life. There is also the BARF diet which stands for bones and raw food. This is claimed by some to be healthier for your dog due to its fresh approach; however home-prepared diets need to be carefully balanced between protein, fat, vitamins and amino acids.
There is only a limited amount of scientific evidence which suggests the effects of diet on your dog's behavior. Food that can appear to suit one dog may cause another dog to be difficult and badly behaved. If you are having issues with your pet dog around behavior it is definitely worth considering altering your dog's diet. If your dog shows unwanted behavior half an hour after eating, every time he eats then your dog may be allergic to the food you are giving him.
You have to be resilient when it comes to feeding your dog. Different breeds of dogs have varying energy requirements. For instance, a nursing mother will need much more energy to feed her puppies and a working dog such as a police dog will need more energy as it is working all day. If you have had your dog neutered they will also need less energy than a dog that has not been neutered. Always be conscious that you need to try and keep your dog at his ideal weight. If you practice lots of training with him, you could allow for extra treats during training.