I’ve had this happen twice as my dogs age. For some reason, they can no longer tolerate the food they’ve been eating.

So this post is all about how to change your dog’s food.

Certainly you should speak with your veterinarian first. You want to make certain your dog doesn’t have something else going on that could be causing his upset stomach. If your vet does recommend changing his food, this is what’s worked best for us.

Talk to your vet about what types of food she recommends. Do you research on the various options. Some are a lot healthier than others. Some are a lot more expensive than others. I don’t the most expensive is always the best choice but the least expensive probably isn’t the one you want.

My biggest recommendation once you determine which food you’re going to try is to make the switch gradually.

As long as your vet says it is okay to continue feeding your dog what he has been eating, cut back on his regular food by a small amount and replace the amount with the new food.

On day 2 or 3, start feeding him 75% of his old food and 25% of his new food. Feed him this ratio for a week. Then switch to 50/50 for a week. Then 75% new food and 25% old food. If he’s tolerating the 50/50 just fine, hopefully he’ll tolerate 75/25 and you can feed him 100% of the new food within a few days of switching to 75/25.

Switching his food over for some dogs may take a few weeks. Other dogs might tolerate a faster change.

In some instances you may need to change the food more quickly if you can no longer feed him his regular food. In that case, I’d recommend feeding him smaller amounts of food more frequently.

Be sure to monitor your dog closely as you are changing his food. Common symptoms that can occur if it’s changed too quickly are diarrhea, vomiting and lethargy.

Best of luck if you have to go through this and as always, be sure to consult with your veterinarian.