What is the Right Diet?

There is no one right diet for all pets. The basic requirement for a diet is that it is complete and balanced, i.e., has all the nutrients required in the correct amounts. Some foods sold are meant to be complementary (e.g., treats) and not fed as the sole food. The label should state that it is complete diet.

It should be formulated for the species intended, e.g., cat or dog and for the life stage of the pet. The nutritional life stages include growth (puppies and kittens), adult maintenance, and reproduction (pregnancy and lactation). Most good diets for growth are adequate for reproduction. Other dietary considerations in otherwise healthy animals include obesity, seniors/geriatric pets, and working dogs. The calorie density (e.g., kcal/100 g) of the diet should be appropriately high for pets who tend to be thin and low for those who gain weight easily. Weight loss diets are the best choice for overweight pets needing to lose weight. Therapeutic diets for disorders should be fed with the advice of veterinarians; veterinary nutritionists can help with these choices.

Regulation of Commercial Diets

How to tell if a diet is complete and balanced? In the European Union the diet should meet the FEDIAF nutrient requirements. In the Americas and much of Asia, the Association of American Feed Control Officials nutrient requirements are used. As noted for life stages there are nutrient requirements provided for adults, reproduction, and growth, but currently not for seniors/geriatrics. FEDIAF is working on information for senior dogs.

EU legislation has a code of practice for labelling and a good practice for safe manufacture. This means that commercial pet foods should be free from unacceptable contamination and that the label has to provide information about the nutrients and ingredients. The principle display panel, usually on the front of the bag or package, contains information about the target animal, e.g., cat food or picture of cat, the net wet weight and may also have bursts and flags e.g., “new and improved”, “preferred by cats everywhere” and a product picture and slogan.

The statutory part of the label includes the ingredient list in descending order by wet weight and the typical analysis (guaranteed analysis in USA). In the EU the ingredient list can be listed individually or by general terms, e.g., lamb, rice, chicken, maize, or by meat and animal derivatives and cereals and derivatives of vegetable origin. The list may or may not be an indicator of quality. Meat derivatives include “by-products” or “secondary products”. These are the part of a slaughtered animal which humans chose not to eat, often for cultural reasons rather than nutritional ones. Many by products are a good source of nutrition and their use in pet foods means that these parts of the slaughtered animal are not wasted. It also means that there is less competition with the human food chain. Without the use of by-products many owners would not be able to afford to feed their pets a compete and balanced diet.

The typical analysis includes percentages of crude protein, crude fat or lipid, crude fibre (which is mostly insoluble fibre), and ash. The amount of moisture should be on the label if it is over 14%. Many owners find understanding the nutrients in wet vs. dry foods and converting these to dry matter is helpful. In the EU the calorie content of the food is not required to be on the label. It can be estimated from the typical analysis.

Comparing Diets

What Makes a Diet Expensive?

More expensive diets may use high quality ingredients. They also may use a fixed formula, so that the diet contains the same ingredients every time regardless of cost. Open or variable formulae use ingredients that meet the label requirement but may vary depending on the cost, e.g., turkey vs. chicken for poultry. Pets who have a food sensitivity often require a fixed formula diet; others are much less likely to benefit. Some larger companies also have very high-quality control of their ingredients and processing. Finally, some diets have added “functional foods” such as added anti-oxidants, prebiotics, omega-3 fatty acids, L-carnitine, chondroitin sulphate/glucosamine, green lipped mussel extract, or other ingredients with a positive effect on health.

Marketing Terms

Hypoallergenic has no meaning as a general term, as what an individual is sensitive to depends on their exposure. Human grade food is also ambiguous, although AAFCO is exploring a definition. In the USA the FDA’s regulation of pet food is similar to that for other animal foods. The Federal Food, Drug, and Cosmetic Act (FFDCA) requires that all animal foods, like human foods, be safe to eat, produced under sanitary conditions, contain no harmful substances, and be truthfully labeled.

“Natural foods” are perceived as better or more wholesome by some owners, although there is only definition guidance but no legal definition or regulation. In the UK the Food Standards agency states that a “natural” product is comprised of ingredients produced by nature, not the work of man or interfered with by man.

The definition of “organic food” varies in different parts of the world. In the EU it generally means avoidance of synthetic chemical inputs, irradiation, and the use of sewage sludge; avoidance of genetically modified seed; use of farmland that has been free from prohibited chemical inputs for a number of years (often, three or more); adhering to specific requirements for feed, housing, and breeding of livestock; detailed written production and sales records (audit trail); strict physical separation of organic products from non-certified products; and periodic on-site inspections. Denmark has the world’s largest percentage sales of organic products (for humans) at 9,6% in 2016.