Signs Your Dog's Diet Needs to Change
July 17, 2025
Sometimes, your dog’s diet needs to change. Whether it’s due to allergies, too much energy (or not enough), or simply changes in preference, your dog’s food will rarely stay the same for an extended period.
Though, changing a dog’s diet isn’t as simple as suddenly switching to a different brand or protein base. There are some logistical considerations to make when transitioning between dog foods. Here, we walk through some signs that your dog may need to change its diet, while providing some tips on how to switch dog food effectively.
Signs Your Dog Needs Different Food
Before we get into the practical side of transitioning to new dog food, let’s start by looking at some of the early indicators that a change in dog diet is needed.
Loss of Appetite
Everyone has preferences when it comes to their food, including your dog. As they mature, a dog’s palate can alter, leading to them suddenly disliking foods that they previously adored. If you find your dog is picking up their food and spitting it back out, they might want something different.
Read more: My Dog's a Picky Eater, What Do I Do?
Allergies
Just like humans, dogs can develop allergies throughout their lifetime. Sometimes, those allergies may be in relation to an ingredient that’s found in their current supply of dog food. This can cause them to develop an allergic reaction: changes to their skin, hair loss, scratching, vomiting, or infections. In these cases, a hypoallergenic diet for your dog may be the answer.
Physical Conditions
Pain can put a dog off its food in a major way. Dental pain, often caused by foods that are too tough to chew, can make it physically impossible for your dog to eat certain types of food.
Lethargy
Sure, sometimes, dogs can have lazy periods where they sleep for the majority of the day. Though, the cause of this can sometimes be linked to their food. If it’s not nutritious enough or too low in energy, your dog may become lethargic or lack motivation.
Skin & Coat Health
Your dog’s food can have a significant impact on its physical being, including things like coat condition and skin health. If your dog suddenly develops a recurring itch or you see signs of dandruff, it could be due to their food.
Weight Gain
Different dog foods will have higher levels of fat content than others. If not considered carefully, this can cause your dog to gain weight at a much faster pace than they’re used to.
How to Switch Dog Food
So, you’re keen to try something different with your dog but want to know some effective tips for doing it smoothly. Don’t worry, we can help.
Note: Before making major changes to your dog’s diet, please speak to your vet. While dog food can sometimes contribute to changes in your dog’s appearance or health, there might be other hidden factors at play.
Transitioning Between Dog Foods
Slowly changing your dog’s food is perhaps one of the smoothest ways of getting them used to a new protein, taste, or kibble size. While it can take longer, gradual transitions are often hailed as the most effective method.
To help you visualise the process, we’ve broken the whole transition down day-by-day:
· Day one: 25% of the food given to your pet on this day should be the new variety.
· Day two: Continue as per day one. No major changes just yet.
· Day three: Increase the ratio of new food to 50/50,
· Day four: Continue as per day three.
· Day five: Increase new food to 75% of the portion, leaving 25% of the old food.
· Day six: Continue as per day five.
· Day seven onward: Increase new food to 100%
By day 10, your dog should be used to their new food. On the days in between changes, you can also offer the new food as a replacement for their treats, which can help make the process a little bit smoother.
Nutritional Guidance and Tips, From Fish4Dogs
Fish4Dogs has backed the use of nutritious fish-based dog food for two decades. Since 2004, we’ve championed fish as an excellent protein for your furry friend to enjoy.
For more information on how to keep your dog fit and healthy with the power of dog food, see our other blog articles.

