What about pet food made with completely natural ingredients and no additives?

Well, it's still not a species appropriate diet, and quite apart from your canine friend missing out on the mental, psychological and physical stimulation that a meaty bone offers as well as the massaging, scrubbing and flossing action that the slicing and tearing action of ripping apart whole, raw meats and meaty bones provide to keep gums healthy, teeth clean and white, and jaws strong, there is another more sinister aspect to pet food that not many people realise...

The extremely high temperatures these foods are cooked at.  It is these high temperatures that account for much of the disease that is attributed to pet food.  The Hunza People, who live in the mountains of North Pakistan, are testament to a raw, species appropriate diet as nature intended as they eat a mainly vegetarian diet, eaten raw, and most live up to between 120 and 140 years of age, and even when elderly they are still fit, full of vitality and virtually free from disease.

Dogs are said to have a genetic age of 24 years and certainly out of the World's Oldest Dogs, up to 32 years of age, none were routinely fed commercial pet food, all were fed variations of either raw or some other form of home made food with very little exposure to the toxins created by cooking food.

This article, written from a human food perspective, explains the consequences of cooked versus raw food very well...

What Your Dietician Probably Doesn’t Know about Cooked Food
By Susan Schenck ~ May 17, 2009

Did you know that a species — living in the pristine wild and eating natural, uncooked food — typically lives to seven times its maturation rate? By these standards, you should live to be 140! So what went wrong? Why are humans getting sick, often at half our potential lifespan?

Most dieticians are trained in creating diets according to the person’s health issues. However, few of these diets stray far from the standard American diet (whose acronym is appropriately “SAD”, which is mostly cooked, pasteurized, or otherwise heated. This is because most dieticians haven’t a clue about some of the most important studies which reveal how toxic a cooked food diet is.

Research by Dr. Paul Kouchakoff (and later Dr. Howard Loomis) has proven that when you eat cooked food, your white blood cells increase. This means your body is trying to fight off an invasion. But if you eat the food raw, this phenomenon doesn’t occur.

In 1916, Louis Maillard proved that cooking creates an endless chain of toxic molecules now called “Maillard molecules.”

Cooking foods above 118 F not only destroys the enzymes and other nutrients, but also creates chemical chaos which people will never be able to adapt to because of the unpredictability of the chemicals. This explains why people who eat a large percentage of their diet as raw foods are more youthful, energetic, and healthy.

What happens to the macronutrients in cooked food? Carbohydrates, proteins and fats are known as macronutrients. All are greatly denatured by heat, becoming toxic to us.

Cooked carbohydrates are alarmingly toxic. In the spring of 2002, Swedish officials were so alarmed by recent research findings that they decided to inform the public immediately rather than wait for them to be published in a scientific journal. Shortly afterwards, the World Health Organization held a three-week emergency meeting to evaluate the Swedish scientists’ recent discovery. They learned that starchy foods, such as potato chips, french fries, baked potatoes, biscuits and bread, contain very high levels of acrylamides, chemicals that have been shown to cause genetic mutations leading to a range of cancers in rats.

Acrylamides are 1,000 times more dangerous than the majority of cancer-causing agents found in food. They have been found to cause benign and malignant stomach tumors, as well as damage to the central and peripheral nervous system. The US Environmental Protection Agency considers acrylamides so dangerous that it has fixed the safe level for human consumption of them at nearly zero, allowing for very little in public water systems. Yet the amounts found in an ordinary bag of potato chips is 500 times the amounts allowed in a single glass of water by the World Health Organization.

At one time, there was a law in force in California requiring potato chip manufacturers to put cancer warnings on their packages! Most did not comply with the law. There were also supposed to be cancer warning labels on the food most ordered at American restaurants: French fries! Would parents who fed their children fries and chips have been charged with child abuse?

Unfortunately, this law was superseded by national legislation that prohibits states from enacting food contamination standards and warning labels that are stricter than federal requirements. Lobbyists from food companies succeeded in getting Congress to pass this bill.

In addition, cooked carbohydrates contain glycotoxins, one of which is an “advanced glycation end product” (AGE). AGEs contaminate the body, making it vulnerable to cancer and molds, such as Candida albicans and other yeast infections.

The May 2003 edition of Life Extension magazine discusses AGEs, referring to a new study published in the Proceedings of the National Academy of Sciences. Eating food cooked at high temperatures was proven to cause the formation of AGEs, which accelerate aging. AGEs also cause chronic inflammation, which can lead to devastating, even lethal, effects directly involved with diseases like diabetes, cancer, atherosclerosis, congestive heart failure, aortic valve stenosis, Alzheimer’s and kidney impairment.

The article declares, “Cooking and aging have similar biological properties. The process that turns a broiled chicken brown illustrates what happens to our body’s proteins as we age. As the proteins react with sugars, they turn brown and lose elasticity; they cross-link to form insoluble masses that generate free radicals (which contribute to aging). The resulting AGEs accumulate in our collagen, skin, cornea of the eye, brain, nervous system, vital organs and arteries as we age. Normal aging can also be regarded as a slow cooking process.”

The glycation reaction cross-links the body’s proteins, making them barely functional. Their accumulation causes cells to emit signals that produce dangerous inflammation.

The book Diet, Nutrition and Cancer also cites studies in which the frying of potatoes and toasting of bread formed mutagenic activity. The authors explain, “The browning of food results from the reaction of amines with sugars.” They cite studies that show that “the increase in mutagenic activity with time paralleled the increase in browning.”

Cooking meat changes the molecular structure of some of its proteins, rendering them unusable by the body and making cellular healing, reproduction and regeneration difficult. The protein molecules become bound, making them harder to digest. Up to 50% of cooked proteins that one eats will coagulate and cross-link. Cross-linking of proteins is associated with Alzheimer’s disease.

Because of coagulation, the protein is 50% less assimilable, as research showed at the Max Planck Institute for National Research in Germany. This means that a person needs to eat twice as much protein if it is cooked as opposed to raw.

Even meat cooked at low temperatures produces mutagens. The book Diet, Nutrition and Cancer explains that mutagens in beef stock have been found in temperatures as low as 154° F (68° C). Frying fish with heat as low as 374° F (190° C) also produces mutagens, as does broiling hamburgers at 266° F (130° C).

Cooking protein above 104° F (40° C) begins to produce toxins. Higher temperatures create even more dangerous toxins, such as heterocyclic amines (HCAs), which are caustic compounds that have proven to cause cancer in laboratory animals. Some HCAs are so toxic to the neurotransmitters and their receptors in the brain that they eventually cause brain diseases, such as Alzheimer’s, Parkinson’s and schizophrenia.

Grilling is one of the worst ways to cook meat. The high temperatures of charcoal broiling and grilling create polycyclic aromatic hydrocarbons (PAHs). PAHs have also been found in smoked meats and roasted coffee.

Cooked fats have been known to be toxic for some time. Fats heated above 96° F (36° C) create lipid peroxides, which are oily, oxidizing compounds, proven carcinogens. Heating unsaturated fats, those liquid at room temperature, at high heat produces trans fatty acids, which create toxic free radicals in the body that cause cancer, aging and liver toxicity.

Heated fats lower the blood’s capacity to carry oxygen and also block capillaries with fat globules. Fatty deposits then accumulate on the vascular walls and contribute to atherosclerosis and other forms of heart disease. Heart disease is currently the number one killer of Americans, with cancer coming in a close second. Heated oils come loaded with mycotoxins, toxic byproducts of the microzymas.

Processed foods usually contain hydrogenated or partially hydrogenated oils. Just read the labels. They are often found even in “health food stores.” This type of cooked fat is solid or semi-solid at room temperature and was created by food oil refiners to create products like margarine to compete with saturated animal fat products like butter and lard.

The trans fatty acids they contain raise the “bad” cholesterol (LDL) levels while lowering the “good” cholesterol (HDL) levels, thus increasing heart disease risk. In fact, they have proven to be much worse than the saturated animal fats they compete against in the marketplace. Fortunately, knowledge of how bad trans fats are has gone mainstream enough to force food manufacturers to change.

The FDA required labelling of trans fats starting in 2006. But there is a legal loophole: if the food has less than half a gram per serving, it doesn’t have to be listed. The way to outsmart food companies (if you insist on eating processed food, which is ill-advised) is to count the number of grams from each type of fat. Subtract this total from the total grams of fat, and that would give you the amount of trans fat the food company tried to sneak past consumers.

David and Annie Jubb write, “All cooked fat, and pig fat especially, is unable to combine with water, causing it to separate out and be stored in the body. Cooked fats are not miscible with water, so they travel separately making blood sluggish, eventually being stored” (Secrets of an Alkaline Body, p. 25).

One of the 66 studies found in The Live Food Factor was conducted by a doctor in charge of a hospital in Australia. He put half his patients on a cleansing diet of raw fruit and no drugs, while the other half was kept on hospital food and the routine medications. After a few weeks, the head nurse stopped the experiment. She found that the patients on raw foods, without drugs, were getting much better, and felt it wasn’t fair to the other patients!

If none of the above convinces you, try this experiment. For two weeks, eat only uncooked food. There are plenty of great recipes online. Then eat your favourite cooked dinner. Be sure to eat this dinner on a Friday night so you don’t have to call in sick from work! People who have done this report feeling “drugged” or “hung-over,” often with “flu-like symptoms.”

When you think about how toxic cooked food is, it is really a wonder that we are still alive and that mankind has survived for so many generations. This is only because humans, along with rats and pigs, are some of the most versatile and genetically hardy of species. However, think how much longer and better we could live if we stopped this ancient practice that is clearly killing us prematurely.

No doubt about it, we are playing with fire when we cook. Grilling, barbequing and microwaving are the worst. The higher the temperature and the longer the time, the more toxins form. If you must cook—steaming, lightly sautéing or heating with a wok are the least harmful methods. And if you must heat with oil, coconut oil (a highly beneficial saturated fat) is the most stable and resistant to forming toxins while heating.