This is a follow-up to my last post and other posts emphasizing the importance of portion control in the present pet obesity epidemic. Veterinarians and representatives of pet food companies continue to beat-up clients about feeding, or overfeeding, their pets. Owners leave veterinary hospitals feeling guilty for causing a host of future problems to their pets by their feeding practices. But guess what? Health care providers cannot do any better with pet portion control. A 2010 study from the United Kingdom is testimony.
The Study
Four veterinarians and six employees of a major commercial food manufacturer participated in the study. They fed six different diets — four feline and two dog dry kibble products — from three different manufacturers to cats and dogs using measuring cups provided by the manufacturer. The manufacturer recommendations were followed and each portion was shaken to level the food in the provided measuring cup. The food was weighed before feeding to document the actual food amount and calorie content for the study statistics. The statistics were then analyzed after the completion of the study.
Despite attempts to accurately measure the food amount, these health professionals had ranges of feeding amounts from 18% underestimated or inadequate amounts to 80% overestimation and excessive feeding. When multiple “feeders” were involved the quantities were the worst. Feeding small amounts to small cats and dogs had the greatest degree of overestimation. Precisely the group that every calorie counts! What is even more shocking is that two of the diets were pre-packaged, just as they are sold to the public, and were fed according to instructions; they were not even accurate.
What Does it All Mean?
Actually, I think there are multiple factors in play. First, is the probable inaccuracy of claims about calories per kilogram that commercial food manufacturers declare on food labels. My research suggests the means by which these figures are arrived at are guesstimates at best and probably vary from lot to lot.
Few pet food labels produce their own product. There are three major millers of pet food in the United States that package the hundreds of commercial pet food labels available. Calometric measurements (igniting the food and measuring its energy) is not required for every lot of food or combination of ingredients. It is not even clear if it is required at all, and calorie counts are derived by mathematical formulas. Estimation of calories are only required for the initial application of the formula. AAFCO is very lenient for the nutritional content of “families of foods.”
My point is that calorie claims made by manufacturers only approximate reality because the production process involves so many unsupervised steps.
Secondly, the calorie concentration in commercial food is extremely high. With counts near 400 calories per cup, each kibble piece is a calorie bomb. Simple, unintentional measured variations of leveling a portion measurement may mean the difference of 25-100 calories. For small or inactive dogs this is a significant difference. Pet owner obsession with the economical and convenience qualities of kibbled food means this problem is likely to get worse.
Thirdly is that proper pet nutrition is a dynamic process and not static. Owners cannot just settle on a portion and assume that it never changes. We have discussed many influences that affect diet in this post. Label instructions today may not be appropriate tomorrow. Most humans don’t even eat correctly. How many families do you know who employ a registered dietician in addition to their house cleaning service, garden care service, car washing service, and pool cleaning service? All seem essential except the nutritional advice. We simply do not spend the necessary time and money to objectively understand nutrition. We are too absorbed with labeling "good" and "bad" foods and calories, which is a meaningless exercise and has little to do with weight control. Weight is about amounts of food, not the kind of food.
Weigh the food. It is still inaccurate, but it is better than measuring in a cup. Also realize that any recommendation is exactly that, a recommendation. Quantities need to be changed based on the body condition score (BCS) of your pet at any given portion. Reduce or increase portions based on their BCS.
Dr. Ken Tudor
Image: I know I shouldn't eat this, but... by Benny Lin / via Flickr