People spend a lot of money per year on their pets to buy food for them. A study showed that there were 200 million pets only in the United States in 2006, with an annual cost to maintaining them equal to $40 million, of which $15 million was allocated solely to dogs and cats. Over time, pets become more apparent among and/or with humans so that they seem to be an integral part of families. Since food itself contributes to a pet’s survival and vitality to a large extent, parents in today’s world prefer to feed pets with foods that do not threaten their health.
Today, there are many food items to choose from, depending on price, pet’s lifetime, pet’s size, type of food packaging, ingredients and additives, race, and type of disease if the pet is infected.
Today, choosing the right food for pets has also been influenced by human eating habits and their sciences and technologies, i.e., it has become “humanized”. Food research shows that pets need specific diets. For instance, arginine is essential for dogs and cats, or aminosol to avrin and preformed vitamin A are especially required for cats.
Furthermore, studies are extensively investigating the positive effects of fatty acids, carotenoids, dietary fiber, and salt balance, and striving to know the usefulness of meat protein and fat in a diet.
For the preparation of preformed diets, meat and bones, poultry by-products, and fish and seafood (as the main source of protein) are the main ingredients. In general, these sources are rich in protein of high-quality in which the essential amino acids are found adequately and in balance.
However, it is noteworthy that the nutritional value or even edibility of these foods after the production and packaging should not adversely be affected by the following conditions:

• Using high temperature
• Choosing primary sources that only contain fat or bone and have no essential amino acids
• A large volume of salts, and
• Oxidation

Fats such as animal fats, pork fat, chicken fat, and fish oil are great sources of energy in today’s preformed foods.
The balance of fatty acids is a key factor to consider when picking the right diet, where absorbing and burning these fats is typically a major challenge. However, there is a need for comprehensive research on this issue, as most theories about the definite effects of fatty acids are derived from human research.