Switching Dog Foods


This article is a sidebar to our post “Diet, Dogs, and DCM”, which appeared in the November 2019 issue

If this is the first you’re hearing about this issue, please don’t panic and immediately switch your dog’s diet, unless your dog is used to eating different foods. Suddenly changing foods is likely to cause digestive upset in dogs that are unused to it. The longer you’ve been feeding the same food, the more likely your dog is to need time to adjust to something different.

Start by replacing very small amounts of the old food with the new. If your dog is doing well, gradually increase the amount of the new food while decreasing the old. This may take just a few days, or up to a few weeks, depending on how long you’ve been feeding the same thing and how sensitive your dog’s digestive system might be.

Stick with new foods that have a similar level of fat to what you’ve been feeding, at least to start with; it’s more likely that a dog will develop digestive issues if switched from a low-fat diet to one that is higher in fat, particularly if the switch is done too quickly or the dog has been on the low-fat diet for a long time.

If your dog is prone to food allergies, it’s likely he will react quickly with itching and scratching if you feed an ingredient that he’s allergic to. Digestive upset may point toward a food or fat intolerance, or may just be the result of trying to switch too quickly; if your dog vomits or has diarrhea, go back to the old diet until he’s back to normal, then try the switch once more, going even more slowly the second time. If your dog continues to have digestive upset with that food, try something else. Keep a journal of which foods you try and the ingredients in each, and you may be able to pinpoint the ones that cause problems for your dog.

If you have been feeding a limited-ingredient diet because your dog tends to have either allergic (itchy) reactions or digestive upset with other foods, here’s what we would recommend. Start by feeding another food in the same line of foods, so that only the protein source changes. Keep track of which proteins your dog has problems with, and which he does well with. Once you know which proteins your dog can tolerate, try another brand of limited-ingredient diet with a protein your dog is okay with. Continue trying different proteins from the same lines, and different brands of foods using those proteins to get a better idea of which ingredients cause problems for your dog. Once you’ve identified the actual ingredients that your dog has trouble with, you can then try branching out into other foods that are not limited-ingredient diets.

We know that many people feed the same food to their dogs all the time because it’s easier, or because they think it’s better (since that’s what dog food companies and many vets recommend), or because they tried a different food once or twice and their dog didn’t like it or didn’t do well on it. In these cases, we still recommend trying to switch your dog to a different diet, or preferably multiple diets using different brands of foods and different primary ingredients. We still believe that this approach is not only more likely to prevent DCM, but also helps prevent food allergies from developing, and provides protection against any nutritional deficiencies or excesses found in any single diet, as well as issues that lead to recalls.

For those who feed a rotational diet, we advise restricting foods in at-risk categories to less than half the overall diet. That means if you feed just one or two foods, neither should be in any of the at-risk groups we describe. If you feed three or four different foods, one can be among the at-risk categories. If you feed five or six different foods, two can be among the at-risk categories. Foods that fit into more than one of the at-risk categories are likely to be a higher risk than foods that fit into just one; the more categories a food fits into, the higher the potential risk. At least half the foods you feed should have: common meats such as chicken, turkey or beef (not lamb), multiple (not limited) ingredients, little or no legumes, and moderate to high protein.