Understanding Pet Food Labels

The question of what to feed your pet is not an easy one. Most of the available information about pet nutrition comes from biased sources-dog food companies, "alternative" dog food producers, or proponents of raw diets who may or may not go overboard in their rejection of conventional wisdom. While some vets recommend a particular brand, vets have told us that that choice has more to do with effective marketing than with evidence. Always keep in mind that pet food is a big, and extremely competitive, business.

Experimenting with different dog foods is not a good solution. Dogs' digestive systems are slow to adapt to a new food. When changing foods, experts recommend mixing the old with the new for at least two weeks. Once the adjustment is complete, you will get an idea of the food's palatability and its effect on your dog's stool, but aspects such as effect on his or her coat and the amount needed to maintain a healthy weight will require months to find out. Whether or not it prepares your dog for a healthy old age will be a matter for guesswork.

Fortunately some objective information about canine nutrition and dog food labels is available, armed with which we can make semi-informed choices.

AAFCO definitions and feeding trial statement
Pet foods are regulated under AAFCO, the American Association of Feed Control Officials. Ingredients listed on the label conform to AAFCO definitions. By carefully reading the definitions, you can learn whether a protein source comes from fresh, slaughtered poultry or livestock, or may be rendered from deceased carcasses-and you can find out just what is, and is not, in "by-products."

All labels contain one of two statements. The first, less desirable, states that the food was formulated to meet AAFCO requirements for feeding the appropriate species (and age). The second, more desirable, states that AAFCO feeding trials demonstrate that the food provides adequate and complete nutrition for the appropriate species and age. This is desirable because ingredients interact in complex ways in the gut, making nutrients more or less available than might be predicted from the formula alone. The only way to judge whether a formula is effective is to feed it to a number of dogs and monitor their health long-term.

Fat
Fat contributes the most energy (calories) per gram of any food component, so if your dog is underweight, feeding a food with a higher fat content may be an option (if your dog is overweight, reduce the amount fed). Dogs are adapted to utilizing fat as energy; unlike us, who derive energy for a short time after a meal containing carbohydrates, dogs are better off resting after a meal, allowing greater blood flow to the digestive system. Fat is also a source of essential fatty acids, which are required nutrients, and contributes to healthy skin and shiny coat.

Protein
Protein is needed daily for synthesis and repair, and studies show that adequate protein levels decrease the frequency of injuries. Protein is the main component of muscle, skin, hair, and other tissues. Waste protein is removed by the kidneys and becomes an issue when kidney function is compromised.