Can Changing A Dog Food Cause Behavior Problems?
Figuring Out What Causes Aggression in Dogs

If you’re like me, you may never have imagined that dog food and behavior problems could be related. If you google “Can dog food cause aggression?” very few articles show up that talk about food sensitivities causing aggression.

When reading about aggressive behavior, most articles you find either define the different types of aggression or list possible medications.

Other articles place the blame on the owner, implying they are causing the aggression to occur because they aren’t “alpha” enough.

On the positive side, there are many helpful articles that teach you training methods that reduce your dog’s stress and build their confidence (reduce fear) in potentially reactive situations. Educating yourself about how to reduce fear aggression in dogs or how to stop resource guarding in dogs is an important step to take if you have a dog exhibiting aggressive behaviors.

What frustrates me is the limited amount of information on the internet about the possible causes. The articles I could find discussed causes I couldn’t control: hormone changes, genetics, brain tumors…not much you can do in those situations.

My Dog’s Aggression Journey

Tico is a border collie German shepherd mix (we think). When he was around 7 months old, he began showing signs of fearful and aggressive behavior. I read the standard articles on dog aggression, trying to make sense of it.

But something about my dog Tico’s aggressive behavior didn’t make sense. His reactivity would be better on some days, horrible on others. I wracked my brain wondering what could change from one day to another that affected his behavior so much.

The trainer I worked with knew that weather changes could affect behavior. That made sense since I had experienced that when my kids were young. Phases of the moon were also possible behavior influencers.

I didn’t think about diet, until the oatmeal incident:

At the recommendation of Tico’s veterinary acupuncturist, we added oatmeal to his diet. Oatmeal was a “cooling” food, and she thought it might be beneficial.

Within days, his behavior changed from normal to on-alert, then to amped-up. He postured at people and dogs out our windows. Soon he started physically attacking my senior golden retriever Moose whenever he would enter the room. Tico had never displayed any aggressive behavior towards Moose before.

The aggression continued to get progressively worse. One night Tico ran at Moose, barking with teeth showing and snapping at Moose’s face. I started to cry; I knew we couldn’t keep both dogs if this continued – Tico was going to hurt Moose.

Feeling desperate, I wracked my brain trying to think of anything that had changed in the past week. The only thing I could come up with was the addition of oatmeal to his diet.

It made no sense, oatmeal would not cause aggression, right? But, it was all I could think of, so out of desperation I eliminated the oatmeal.

Within days the aggression began to subside, and Tico slowly returned to his normal behavior around Moose.

I searched the internet for articles discussing food as a cause of aggressive behavior and found nothing. But I knew with certainty that when Tico had eaten oatmeal, it had caused some type of chemical change in his brain that made him act aggressively.

It was the start of a long and frustrating road. My goal was to figure out what foods (and other things) were causing his brain to react more aggressively in certain situations.

This incident opened up a whole new way of thinking about reactivity for me. I started trying to educate myself on what factors can cause aggression that I might be able to control.

Why is My Dog Being Aggressive All of a Sudden?

Important Disclaimer: I am not a vet. Not even close. I’m just sharing my own personal experience and the information I have read. If you think you want to try something you read about here, talk to your vet! But first read this and many more articles to empower yourself for a good discussion in which you can ask your vet great questions about what you want to try.

Knowledge is power – never forget that!

dog being aggressive all of a sudden at passing dog

When a dog you have known for years starts showing aggressive behavior, it’s shocking and heart breaking. You know the potential of your dog to act sweet and loving. So why do they act so different in certain situations?

The first thing you want to do is take the dog to the vet to investigate any medical causes. The vet will run bloodwork and check for any signs of pain that your dog may be experiencing.

Before you go to your appointment, read through these possible causes of aggression so you can discuss them with your vet.

What Causes Aggression in Dogs?


Genetics can play a part in aggression in multiple ways.

If your dog had an aggressive parent, they may have inherited some of their aggressive tendencies. One of my past dogs who showed increasing reactive behavior as he aged turned out to be from a mother who had THREE brothers euthanized for aggression. Not helpful to find that out after owning him for years, but it helped explain the aggressive behavior.

Another genetic factor comes from the dog’s in utero experience. Was the mother stressed? Underfed? Nutrient-deprived?

Patricia McConnell wrote a great article discussing how Fear in Dogs May be Influenced by In Utero Experience. This is a growing area of research and discussion. Preliminary knowledge is based on studies of humans, such as this study in which maternal stress during pregnancy was significantly correlated with infant cortisol reactivity after birth.


Puppies miss a crucial socialization period when they are pulled from their litter too early. During this time, their mother and siblings teach them important lessons about playing and interacting with other dogs.

We think this is a factor in Tico’s aggression. He came to rescue as a tiny puppy, and we think he was pulled from his litter too early.

Socialization needs to continue once a dog is placed in a home. The goal is to expose the dog to many different situations and settings so they develop comfort and confidence in changing environments.


When a dog starts showing aggression out of the blue, the thyroid can be the culprit. Many vets do not check this, so it’s up to you to advocate for your dog and have the thyroid level tested.

I highly recommend having your vet send the dog’s blood draw to Dr. Jean Dodds and her staff at Hemopet. Hemopet does an age- and breed-specific analysis of your dog’s thyroid levels that flags levels that may be overlooked as “low end of normal” by a vet who doesn’t specialize in the thyroid’s effect on behavior.

Injury or Chronic Pain

Sometimes pain can be the cause of aggressive behavior. If your dog has an injury or is experiencing chronic pain, they may react toward other animals or humans who get too close or are unknowingly touching the painful area.

I found a heart-rending story that illustrates how pain can cause aggressive behavior. This poor dog was growling to try and keep people from touching a painful area of her body. Many dogs are unnecessarily and inhumanely euthanized because their owners fail to investigate this possibility.


Extreme medical conditions such as brain tumors can alter a dog’s behavior.


Don’t rule out poor eyesight as a cause of aggressive behavior. I read a story about a 5 month old dog who was barking aggressively and snapping at people who approached him. After some pretty intelligent observations and troubleshooting, the vet determined that the dog was aggressive because he had juvenile cataracts and couldn’t see approaching people well.

Nutritional Deficiency

Hormones and neurotransmitters regulate dog behavior. Changes in the availability of nutrients, amino acids, and enzymes that help form and regulate these hormones and neurotransmitters may influence your dog’s behavior.

For example, emerging research suggests that levels of tryptophan and DHA (from fish oil) may reduce aggression in some dogs because they can increase serotonin availability in the brain.

This article on the impact of nutrition on canine behavior discusses a number of publications that have studied this phenomenon.

Poor Gut Health

Studies in humans have shown that poor gut health can affect anxiety and behavior. Could similar findings be true for dogs?

A small study conducted by Purina (Impact of Diet on Anxious Behavior in Dogs) found that a certain probiotic (B. longum BL999) had impressive results on anxiety.

24 anxious labrador retrievers were split into two groups. One group was given a Purina probiotic product called Calming Care, which contains B. longum, the other a placebo.

Researchers then monitored anxiety-like behaviors, salivary cortisol, heart rate, and heart rate variability for 6 weeks.

After 6 weeks, all dogs were taken off supplements for 3 weeks, then the groups were reversed (initial placebo group received Calming Care, initial Calming Care group received placebo).

After 6 more weeks, the results were impressive:

  • 22 of 24 dogs showed a significant reduction in barking, jumping, spinning, and pacing while on Calming Care
  • 20 of 24 dogs showed reduced salivary cortisol concentrations when exposed to anxiety inducing stimuli while on Calming Care
  • 18 of 24 dogs had a decrease in heart rate, and 20 of 24 dogs had increased heart rate variability (both a sign of decreased stress)

I give Tico Calming Care as well. When I started giving it to him I did notice subtle but positive changes in his behavior. He is obviously also affected by food sensitivities, so Calming Care didn’t perform any miracles, but I think it gives him a more solid intestinal health base to build on.

Purina Calming Care


Food sensitivities as a possible cause of behavior problems is a relatively new area of exploration. Preliminary studies are showing what some of us have seen firsthand in our dogs: food sensitivities can cause behavioral changes, including aggression.

Read on to discover more about this emerging discovery.

Dog Food and Behavior Problems

During the first few years of Tico’s aggression I started to wonder why his reactivity was so up and down. One day he would do a great job when seeing dogs or people on our walks, and I would of course think “Yay! Our training is working!” Then two days later we would have similar training opportunities and he would act like a raging lunatic.

It made no sense. I was doing the exact same training protocol. The dogs or people we saw, as far as I could tell, had no glaringly different behaviors that might make him respond differently.

So why was his aggression so unpredictable? I started to wonder . . . could the treats I was using, or the food I was feeding him, be changing his behavior?

confused woman wondering why is my dog being aggressive all of a sudden

Lack of Studies About Dog Food and Behavior Problems

When asked “Can dog food cause aggression?” many vets still shake their head and discount the idea. Most vets rely on scientific studies to learn about the causes of and solutions for aggressive behavior, and there is a significant lack of studies investigating possible links between dog food and behavior problems.

Studies are emerging, however, that are starting to look at isolated relations between food components and behavior:

Protein & L-tryptophan

A study published in the Journal of the American Veterinary Medical Association investigated the relationship between dog aggression and dietary protein content and/or L-tryptophan supplementation.

The science behind it is a bit of a brain drain, but here’s a simplified version:

L-tryptophan is an amino acid needed to form serotonin in the brain. Serotonin, in turn, can help reduce aggressive responses to stimuli.

Protein contains low amounts of L-tryptophan, but high amounts of a large neutral amino acid called LNAA. LNAA uses the same transport mechanism to cross the blood-brain barrier as L-Tryptophan – so you could think of them competing for the transport mechanism to get into the brain.

The hypothesis for this study was that lower protein would lessen the LNAA, allowing more L-tryptophan to get to the brain.

They also had one study group that was fed supplemental L-Tryptophan in addition to the low protein diet. This was building on results from a previous study about adding L-tryptophan to reduce aggression which showed inconclusive results for only adding L-Tryptophan to dogs’ diets. In its conclusion it recommended that, in future studies, L-Tryptophan be added while also lowering protein to see if that would improve the measurable response.

Results showed promising evidence that both low protein diets and low protein L-tryptophan-rich diets may decrease dominance aggression.

In addition, the study showed that low protein diets supplemented with L-tryptophan may be beneficial in reducing territorial aggression in dogs.

Gluten Hypersensitivity

I found a really interesting article in the Journal of Veterinary Behavior that explored the link between gluten hypersensitivity and dog aggression.

It discusses a case study in which a 7 year old dog was exhibiting worsening aggressive behavior that started at age 5. The dog showed no aggression in his first 5 years. Researchers found elevated antibodies indicating gluten hypersensitivity in the dog’s bloodwork results. and put the dog on a gluten-free hydrolyzed protein diet.

Three weeks after the diet change, the dog’s aggression had disappeared.

In the time that followed, the dog ingested carbohydrates two times. Once, he ate the cat’s food, which contained gluten. He became aggressive that same day and for 4 days after, but then returned to normal (no aggression).

In the second incident, the owner changed the dog’s diet to a commercial dog food. After 1 day the dog’s aggressive behavior returned. The owner immediately switched back to the gluten free hydrolyzed protein diet, and over the next 4 days the aggressive behavior disappeared.

Pretty mind-boggling, isn’t it? For me it was validating; I have known my dog reacted to different foods but to hear such a marked example of aggression turning “on” and “off” made me think about the possibility that I might be able to improve Tico’s reactivity even more with more diet refinements or omissions.

The one question I had was, why did they use a hydrolyzed diet? It makes it hard to discern if the behavior changed solely due to the removal of gluten, or if the easier-to-digest (hydrolyzed) protein was also involved.

I emailed the study author and will update this article when/if she responds.

Too Much Iodine in The Diet

This was another interesting find that could be a possible link between dog food and behavior problems. Feeding excessive amounts of iodine (either through the dog’s food or through kelp/seaweed supplements) can reduce thyroid function. Whether you feed a commercial diet or homemade, check the iodine content to be sure it isn’t too high.

“. . . the iodine concentration in commercial pet foods today is 3-5 times the stated minimum requirement, which causes more problems because excess iodine is associated with hypothyroidism and thyroiditis in dogs (and hyperthyroidism in cats).”

Dr. Jean Dodds, Nutrition and Thyroid Function Affect Canine Behavior and Cognition

Skin Responses to Dog Food Sensitivities

Dr. Dodds published a retroactive study describing food sensitivity and intolerances associated with diet type in golden retrievers. This paper does not discuss behavioral responses, but I included it as it has impressive photos of dog skin issues before and after the offending foods were removed from the dog’s diet.

Behavioral responses to food allergies are very hard to conceptualize as there is no easy-to-see visual change that occurs. But, if you think of them like the skin changes in this study, it helps you conceptualize the “path” that behavioral improvement will follow if it is caused by food sensitivities:

  • Changes are gradual and improve over time, just as the skin improvements in these pictures
  • Over time, the improvement you can achieve if you remove offending foods is quite impressive

If food sensitivities can cause severe skin problems such as the ones in Dr. Dodd’s pictures, it sure seems possible that they could affect body systems that in turn affect your dog’s temperament. (if your dog struggles with skin issues, learn more about how to treat dog allergies naturally to relieve your dog’s symptoms)

How Can I Test for Food Sensitivities?


I would highly recommend Dr. Dodd’s NutriScan test. Some vets don’t believe in the science behind this test, my own vet poo-poo’d it. But, I did my homework, and read many articles that supported it from a scientific perspective.

I did the Nutriscan with Tico and guess what one of his highest food sensitivities came back as . . . oatmeal! That was enough proof for me. I did not submit any information about foods Tico had eaten, just a saliva sample. If the measures of the test identified oatmeal as a trigger food, the people at Hemopet know what they are doing.

Trial and Error

Before I heard about the NutriScan test, I did a lot – and I mean A LOT – of trial and error food experimentation with Tico. This meant only making one change at a time and then waiting 4-7 days to see if I noticed any changes. If I thought I saw increased reactive behavior, I would note that in my log, then go off the food and keep notes on behavioral changes in the following 4-7 days.

Using trial and error to find links between dog food and behavior problems can be hard because other things can affect your dog’s behavior. If they have a run-in with another dog (i.e. they bark like a raging lunatic at a dog who surprises you coming around a corner on a walk), that will increase their cortisol levels and you will see behavior changes for hours or days afterward.

I swear phases of the moon and weather patterns can affect our dogs’ behavior too, just like many moms notice changes in their kids’ behavior from these things.

Trial and error can be tough because you sometimes can’t be sure what caused what. You always have to consider what else is changing or going on in your dog’s life.

Can Dog Food Cause Aggression?

happy dog with owner that figured out the connection between his dog food and behavior problems

There is no doubt in my mind that food sensitivities absolutely can and do cause aggression.

Studies are needed that delve further into the connection between dog food and behavior problems, so that owners like me don’t spend the dog’s lifetime trying to figure out why their dog’s behavior varies.

The studies above give me hope that perhaps in Tico’s lifetime I can find and eliminate enough triggers to help him become less fearful of and less reactive towards other dogs, people, bikes, skateboarders, pickup trucks . . . you get the gist.

If you have had luck identifying a connection between dog food and behavior problems in your dog, please share in the Comments section below so the rest of us can learn from your experiences!

Until next time-



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Dog Reactivity and Food Sensitivities

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Karen Pedersen Written by:

Karen is a freelance copywriter who loves dogs and everything about them. She has fostered dogs since 2005, choosing dogs with medical or behavioral issues that would benefit from her natural and holistic approach to healing. She has gained experience and anecdotal knowledge with each dog she helped, and started this blog to help others do the same.


  1. Michael
    December 6, 2020

    We have a female F1 miniature labradoodle. She is 19 weeks old now and from the moment we took her at 8 weeks from the breeder we fed her a healthy dried food. The breeder gave us a pack of purina but I put it in the rubbish bin immediately: it is junk food My wife and I, both whole food organic vegetarian , are not bringing up puppy as vegetarian but that’s no reason for her to be fed junk.

    Another thing, different topic, I want her to enjoy being a puppy and not have it trained out of her as if human ways are sacrosanct. Jumping up for example is natural behaviour, humans can fend for themselves and it is for us to avoid mixing with humans that cant, not to effectively punish her with treats when she does as we would like. My wife and I differ in our views, my wife wants to train the discipline. But for example what’s the benefit to a dog in being told to sit when so far as the dog is concerned there is no point in sitting. As for puppy running rings around us, so what? My latest example is to realise that having given up trying to find ways to deter puppy from chewing a rug in out living room Ii realise that we are hypocrites: we stand and walk on the tug., what’s the difference?

    Puppy is highly intelligent, bred from good stock, prefers people to other dogs, etc.

    Steep”learning curve for us, even though I have had puppies/dogs before (different breed) Years to go. But taking on board what other dog owners tell us or suggest is one thing, avoiding being over influenced another. Which is why when our puppy eliminates 3 times a day I know she is relieved and relaxed, whereas the vet tells us that once a day is enough. I poo 2-3 times a day, which is how it should be..

    • December 6, 2020

      Hi Michael, Thanks for your thoughtful comments! It sounds like you have a wonderful puppy that is full of exuberance and energy. I understand your desire not to train all of her joyful exuberance away and to let her be a happy puppy, but I also understand your wife’s desire to not have her jumping on her (and visitors) or chewing on household furnishings.

      From a chewing standpoint, I think the first thing you need to consider is the safety of your puppy. If she is chewing stringy items like rugs and tugs, that is dangerous – I have heard stories of the strings clogging or cutting off intestinal flow, here’s an article that discusses how it can happen:

      I think you are wise to point out that the puppy can’t tell the difference between a tug and the edge of a rug – that is very true. I think there are two compromises in this situation: 1) put the rug away for 3-4 months until the puppy’s chewing phase subsides, or 2) put a variety of appropriate chew toys around the room that the puppy considers “more” fun than chewing on the rug. Toys like Kongs with some of the puppy’s kibble inside or other yummy smelling stuff like organic sweet potato puree, yogurt, or peanut butter will give your puppy a fun activity to keep her busy. You can find other toy ideas in this article about mentally stimulating dog toys .

      A final thought is to consider that to a puppy, training (when done is a positive way that sets the puppy up for success) is considered FUN by the puppy! It is positive attention, which she will love, and mentally tiring, which is good for her as well. Add in some outdoor time (consider doing decompression walks !) and that will help you and your wife survive her puppy stage without dampening your dog’s puppy joy.

      Let us know how things go, best of luck to you!

  2. Sonya
    April 6, 2021

    Thank you for sharing your story and insight!! We have recently adopted a 6 mo old Border Whippet and have been struggling to solve her tummy issues. Even more recently, I’ve noticed a pattern of aggression after eating kibble. We’ve been experimenting with a mixed diet – 1/2 raw and 1/2 no carb, high end kibble, as suggested by a nutrionist. After eating the raw food in the morning, she remains an playful, patient, angel. Yet, after a dinner of kibble, she quickly becomes too rambunctious and quite aggressive. I’ve never experienced this with any pet and thought I might be making things up to justify her behavior. After reading this article, I am thankful to know there might be a way to solve this. I would hate to rehome her. That has absolutely never been an option for me, but I also can’t have my family endangered either. I’m rambling. Anyways…
    Thank you for shedding some light on the possibility aggression due to food allergies!

    • April 7, 2021

      Hi Sonya, Thank you for writing! This sounds SO similar to my dog, Tico. Be prepared that as you move through life with your dog, there are *very* few vets who will believe you. Even holistic vets have trouble believing that the food actually directly changes behavior. I went to an awesome vet last week for Tico’s annual checkup, and when I asked if she had seen other dogs with a food/aggression connection, she said that she sees it more as the food makes them feel yucky which could change their behavior. Which could be possible in some dogs, but your case is the perfect example: If your dog felt sick or uncomfortable after eating they wouldn’t become MORE rambunctious they would go lie down! So hold firm to what you see at home and what you about your dog, even if a vet tries to tell you differently. You may help *them* learn!

      One test I might consider is the Hemopet Nutriscan test mentioned in the article, it gave me insight into some of the foods that change Tico’s behavior. And trial and error is big—when you see her behavior change after a meal you know that something she ate triggered the behavior!

      Best of luck as you experiment with what foods are best for her, keep me posted on what you learn. There are so few stories out there that anything you learn will help me and all the other readers on our dog journey.

  3. Kim
    July 7, 2021

    I have been getting a delivery of tails dog food since last Nov for my rescue dog. She was always very gentle but started to get aggressive a month later on walks and shops where she would lunge at people and cars. She’s been on tails for 8 months and I just happened to be staying at my parents for 2 weeks recently and couldn’t get my tails delivery, so I got a pack of Crave kibble just to see her over the 2 weeks. By the time I went back to my own home and started walking her round the park again she was as good as gold, like I changed dog. I then changed her back to tails and a day later she had started the lunging again. The food was the only thing that had changed so I’ve now been feeding her the crave kibble again and replacing the wet food with home made food, and I honestly think she is starring to calm down again. I’m going to carry on with this as an experiment, even though I have a full delivery of tails. If this is the answer to her problems I will be delighted!

    • July 7, 2021

      Kim, that is FASCINATING! It would just be so amazing if your dog suddenly transformed into a “normal” (non-reactive) dog and you can once again enjoy walks and parks. Have you compared the ingredients of Crave kibble vs. Tails dog food to whittle down what ingredients it might be? That might be helpful down the road when you are buying treats – that way you can scan the label for possible problem ingredients. Please keep me posted, it is so nice to hear a story like this and know that my dog isn’t the only one whose behavior was affected by the food he ate. And, KUDOS to you for noticing this and figuring out it was the food, your rescue dog is one lucky girl.

    • Jane
      December 12, 2022

      I too started getting Tails dog food for my 4 year old lurcher. A month in and he had turned from a gentle, friendly fellow into an aggressive beast. I was in despair, so upset and confused about why he had changed so much. He had been the kind of dog that loved to play with other dogs but now a walk in the park became an ordeal. He was lunging and growling and I could no longer trust him off lead.
      Until I read your post!
      I realised that his aggressive behaviour started when he started eating Tails food. So I stopped it and put him back on his old food. Within a week he was back to being gentle and friendly to other dogs again. It was such a relief. I am so relieved and he is such a happy dog again. Thank you for your post.

      • December 13, 2022

        Hi Jane, I’m so happy your dog’s behavior is back to normal, thank you for sharing so others can hear about your experience and have hope!

  4. Amy Trepeta
    December 27, 2021

    Hi Karen! Can you tell me what food you feed? We just switched to an adult dog food (Merrick Backcountry Raw Infused) from puppy (fromm large breed) and have noticed aggressive behavior.
    The backcountry line has several flavors but both have the oatmeal and more protein. Thank you

    • December 27, 2021

      Hi Amy! I switched to a raw diet with Tico, I worked with a vet to come up with the right amounts of meat, veggies, and supplements to make sure all nutritional needs were covered. You could try a limited ingredient kibble, or pre-made raw? Another helpful tool for me was the Hemoscan test by Jean Dodds, which helped me know what foods to avoid.

      Hope that helps, keep me posted on what food you find that works for your dog. 🙂

  5. March 27, 2023

    I have a 6 year old Springer Spaniel.He was born in a vet’s breeder cage and kept there until he was 4 months old then he was given to us when he was 8 months old and for those four months he was very well treated mostly but he had been clearly abused for the first 4 months and he showed clear signs of abuse: anxiety, aggressiveness, shaking, fear, distress at certain triggering situations, like when we grab things very fast, and when we are getting ready to leave the house and he knows we are going out but he is staying at the house, when anyone stands by any door, if he is in bed with one of us and somebody comes close to the bed he completely protects and defends the person and the bed,.As a puppy he was playful but with a touch of aggressiveness, nightmares and sleep disorder patterns for a whole year until finally recovered.Not a 100% but close to an 80%. everytime he has a very hectic day nightmares show up again.He is very loving and playful but he snaps in certain situations. He is very afraid of the cel phone sound, the beep of the alarm system, the sound of tone messages and he starts shaking and goes to hide everytime he hears them. He was fed commercial food for those early months but I feed him homemade.It seems there is a connection between commercial food and homemade food with him everytime I for one reason or another feed him commercial food for a couple of days. Yesterday his anxiety was bad and he went to his safe zone and I tried to get him out and he bit me.His reaction was bad and somehow I believe has to do with the fact that the past two days I fed him commercial food.Could this be possible? He was gasping the night before and acting very nervous and anxious. I am not feeding him commercial food again but I wanted to know if commercial food could affect him so quickly.Thank you.

    • March 27, 2023

      Hi Marta, There has been very little research into this area, but from my personal experience I absolutely believe that what you feed your dog can impact their behavior in some cases. I don’t know why, all I can tell you is that my dog’s behavior changes that occurred after food changes were no coincidence. For me it has been a matter of trial an error: once I notice that a certain food elicits a negative reaction I add it to my “do not feed” list.

      Take a look at this study:, it recorded a dog’s behavior/reactivity improving while on a hydrolized diet. I’m not advocating a hydrolized diet (they come with their own issues), but the study shows that what the dog ate impacted their behavior.

      I think you’re wise to remove commercial dog food if you are noticing behavior changes (just be sure your homemade food account for your dog’s nutritional needs – I worked with a holistic vet to be sure my meals had adequate nutrition).

      I’d also recommend keeping a log of your dog’s behavior and what you feed him. When I did this I noticed there were also times of the year that impacted his behavior. My guess would be that any time he has a sensitivity or allergic reaction (to food or environmental changes) it triggers behavioral changes.

      I hope this helps, please keep us posted on how your dog does, best of luck!

  6. Amy K
    September 5, 2023

    We have a 5 year old beagle who has a Dr. Jekyll and Mrs. Hyde response to so many food ingredients. She began having spastic tremors in her jaw plus having protective snarky, snarling episodes after we changed food brands once our typical food was discontinued. The turning point was when we gave her a Thanksgiving day turkey treat.. She went insane the next day and turned on us. Beagles are known for their easy sweet nature so we were in shock. We took her to the vet and all the tests came back healthy. We did start her on Prozac which helps ease anxiety but not eliminate the aggression. .Our cat is food sensitive to nearly all food ingredients so I started to question whether the beagle was as well. Until the dogfood discontinued, I had kept the dog food ingredients free off some key things like poultry in case the cat snuck a bite. The new dog food had chicken so I switched to poultry free. She got better for a while then behavior returned. Through process of elimination, we have found that all peas/peanut, all poultry, beef, pork, all grains and potatoes are triggers for her to behave truly awful towards us. Only one food is working currently which is limited ingredient Venture Rabbit and Pumpkin. I am hopeful this will be a long term solution because it feels like she can’t eat anything.

    • October 19, 2023

      Hi Amy, I’m so sorry for the delay in reply, your email got caught in my spam filter and I missed it when reviewing spam. Your experience with your beagle sounds heartbreaking, kudos to you for working so hard and identifying all the foods she is sensitive to!

      Have you looked in to Jean Dodd’s Nutriscan test at all?

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