The label on a packet of dog or cat food is an important resource for understanding what kind of diet our beloved companion is actually receiving. Yet navigating the various entries, ingredients, percentages and components is not always straightforward. We asked an expert – Barbara Tonini, a veterinary surgeon with a research doctorate in canine and feline nutrition – to help shed light on this fundamental aspect of our pets' daily diet.

Read also:

• Dog nutrition and the microbiota
• The anti-ageing diet for dogs and cats
• Fruit and vegetables in the diet of dogs and cats

The label and meat content

From a legislative standpoint, the components of pet food must be listed on the label in order of weight, water included. "It is therefore quite logical to expect that ingredients with a high water content, such as fresh meats and vegetables, will occupy the top positions on the list, far outranking those in flour or dried form," explains Barbara Tonini. As a basic ingredient in pet food, meat (or fish) must by law appear on the label.

"It is worth clarifying that the quality of a product is defined by the raw material used as the starting point, not by the processing it undergoes," the expert adds. "In fact, both dehydrated meat and meat meal consist of mammalian tissues, organs included, and blood, hair, feathers, hooves, horns, beaks, skin and the contents of the digestive tract are not permitted. The only difference lies in the heat process to which they are subjected. Dehydrated meat, for example, involves a more rapid drying process that better preserves the original characteristics and extends shelf life."

Meat meals are, in any case, among the main by-products of the animal processing industry, and they help to limit the accumulation of animal by-products. "In this way, nutritional sustainability is improved, guaranteeing a share of high-quality protein and a correct amino acid and mineral balance. Calcium and phosphorus are, in fact, the most important macrominerals in the diet of dogs and cats, and they are readily available above all in animal meals," Dr Tonini continues.

Grain-free pet food

An increasing number of dog owners are drawn to grain-free diets because they are perceived as more natural and less likely to cause allergies and other common gastrointestinal problems. But is that true? "Let me start by saying that there is no reliable evidence to suggest that feeding dogs and cats 'grain free' is harmful; on the contrary, what we do know is that cereals – especially wholegrain varieties or pseudo-cereals – are not only an important source of calories but can also provide valuable nutrients including vitamins, minerals, essential fatty acids and fibre," the nutritionist explains. "Furthermore, it is well established and proven that the digestive capacity for cereals is generally good in both dogs and cats, and that a grain-free diet must necessarily contain high amounts of fats and/or proteins."

Switching to a high-protein or high-fat diet is therefore not always, and not for every animal, the best solution. "One must absolutely not believe that diets with a higher fat content are more digestible and cannot also have unpleasant side effects," Barbara Tonini continues. "Dry kibble must necessarily contain a minimum amount of starch – never less than 15–20 per cent – so one should not assume that 'grain-free' dry foods are carbohydrate-free, because it is physically impossible to produce any kind of kibble without some contribution of this kind." For this reason, manufacturers use other specific ingredients in place of cereals:

• highly refined starch (such as potato or tapioca/cassava starch), which certainly provides fewer nutrients and less fibre;
• legume starch (peas, beans or lentils), which, however, can cause digestive disorders in some animals.

Before switching to this type of food, it is therefore always advisable to consult your own vet to avoid any unpleasant problems.

Pet food ingredients and food allergies

Food allergies in dogs are mainly caused by common glycoproteins found in chicken, beef and milk. And what about gluten intolerance? "This is an extremely rare pathological condition in domestic animals – gastrointestinal symptoms have been confirmed only in one bloodline of Irish setters – and we have no scientific evidence in dogs, let alone cats, of a relationship between gastrointestinal disorders and dietary gluten," Barbara Tonini replies. One must therefore not make the mistake of choosing a food simply because it is "grain free." "It is a marketing concept designed to sell food, not a nutritional characteristic that helps your pet live a longer and healthier life," Tonini concludes.

Read also: Allergies and intolerances in dogs and cats: everything you need to know

What "human grade" means on a label

The term "human grade" is supposed to indicate a product in which the ingredients are "stored, handled, processed and transported" in a manner that meets the legislative requirements for food intended for human consumption. "This concept might well appeal to the majority of owners, but unfortunately it is not feasible for one simple reason: an ingredient intended for pets is by definition no longer suitable for human consumption," Dr Tonini explains. "In any case, ingredients sourced from the human food chain are not necessarily better and therefore more nutritious, healthier or safer than ingredients intended for pet food."

There is not much more to add when it comes to navigating the varied world of food for our four-legged friends. What will always be important is to read the ingredient list and descriptions on the label carefully, even though there is no way to determine the absolute quality of a diet in this way alone. It will also be important to choose a complete and balanced product, never forgetting to seek advice from your own vet and not relying on the superficial – and, unfortunately, often incorrect – opinions found on social media or online. All of this while making sure that the food meets the nutritional needs of the individual animal for which it is intended, and that it is produced by a company that employs qualified nutritionists and operates a controlled, modern production facility.