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Puppy eating adult food, sensitive stomach. How to switch to puppy food?

Updated On September 23rd, 2025

Pet's info: Dog | Mixed Breed Large (61lb +) | Male | 9 months and 7 days old | 70 lbs

Hello! My puppy is 9 months old and 70 lbs. we have an older dog in the house so the puppy has ended up eating the same adult food for a several months now. I want to get him on a grain free food to help his allergies and back on puppy food so he gets better nutrition for his growth. My boyfriend says that going back to puppy food will possibly upset his stomach more than just switching adult foods. He has had a sensitive stomach so I’m worried...Is this true and do you have any advice?

1 Answer

Most Helpful Answer

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Answered By Dr. Kristin DVM

Veterinarian

Published on December 5th, 2018

He absolutely needs to be on a puppy food, unless the "adult" food you are giving your other dog is one that is "appropriate for all life stages". Any time we switch foods we can cause stomach upset. I recommend adding in small amounts of the new food to the old food, and slowly increasing the amount. If Chance has a particularly sensitive stomach, you should wean him onto the new food over a week.

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