4 Questions on Feeding Guidelines and the Modified Atwater Calculation
Some of our (Iams/Eukanuba) feeding guidelines are changing.
1. What’s changing?
In the past, we’ve used feeding trials to figure out the number of calories in our food so that we can set up our feeding guidelines. In 2006 we replaced feeding trials with something called the Modified Atwater Calculation. Since that time, whenever we’ve made changes to our packaging we’ve also adjusted our feeding guidelines so that they are based on the Modified Atwater Calculation, instead of on feeding trials.
Iams dog and cat formulas have already had the Modified Atwater Calculation applied to the feeding guidelines. In the next few months, the Modified Atwater Calculation will be applied to Eukanuba dog feeding guidelines.
Let me emphasize that we (Iams/Eukanuba) always advise people to use our feeding guidelines as a starting point, not as an amount that’s written in stone. A dog or cat may need more or less food depending upon age, activity and temperament. The pet owner knows the pet best, and we encourage pet owners to be responsible for adjusting the amount of food so that the pet gets the right amount for their individualized needs. Your pet’s body condition (Too fat? Too thin? Just right?) is the best indicator of how much to feed.
If you’re feeding your pet one of our diets, and your pet is thriving, there is no need to change the amount you’re currently feeding because you’re feeding to satisfy your pet’s nutritional needs.
2. Why did we do this?
The Modified Atwater calculation is globally recognized by professionals involved in pet food nutrition as the official method for calculating metabolizable energy (calories) in dog and cat foods. Also, it eliminates any of the variables that can happen with live animals and environmental factors. It gives us a more consistent calorie amount comparison across our products. And it reduces the use of live animals in feeding trials.
One of the things I like about the way the new guidelines are presented is that they now give a range of how much to feed instead of a specific amount. For instance, it might say “1/4 — 3/4 cup” instead of “½ cup” which I think encourages people to adjust the amount to meet the individual pet’s needs.
3. How does it work?
The Atwater Calculation is used to figure out the number of calories (a unit of energy) per kilogram (a unit of weight) of food. From that number, we can figure out the amount of food that is needed to feed a dog or cat on a daily basis.
4. Why is it “Modified?”
This kind of calorie calculation was the result of work done by Wilbur Olin Atwater. In 1896, Dr. Atwater headed the federal nutrition program and published a work titled “The Chemical Composition of American Food Materials” which listed minimum/maximum/average values of all known American foods—the first calorie-counting guide!
According to Wikipedia: “The Atwater system (after Wilber Olin Atwater) or derivatives of this system are used for the calculation of the available energy of foods.” His calculations for human nutrition have been modified for dog and cat nutrition.
I’ve put this information in my own words after training and study. I reserve the right to add to and/or edit this post if it becomes outdated or additional/better information becomes available. Information posted on my blog (or on the Internet for that matter) should NEVER be substituted for the guidance and advice of your veterinarian or your animal behavior professional.