From Adult to Senior: When & Why to Change Your Dog’s Diet

More and more pet owners are beginning to understand the
importance of feeding their dogs a fresh food diet and the myriad of benefits
that this can have on their overall health and wellbeing. Modern veterinary
medicine, too, has doubled our canine companions’ lifespans in the last 40
years. Anecdotally, many fresh food feeders seem to find that their raw-fed
pets are aging slower, have reduced “common” aging symptoms like cognitive
decline, and maintain good energy levels and appetites well into their senior

I remember when I took my dog, Chip, to the vet and was first told he was officially a senior- that was in 2015, when his only “symptom” of getting old was a few gray hairs around his muzzle. I laughed out loud and said, “well, what does that mean?” and at the time, I was told that it was just something to keep in mind. For many of us, it’s a tough pill to swallow to accept that our vibrant, healthy dogs are “seniors” just because they reach a certain age while being a certain size. The basic tenant of aging in dogs says that the smaller the dog, the longer the lifespan has the potential to be. If you take a look at the chart below, you will indeed see that generally speaking, large and giant breed dogs become seniors far sooner than small breeds. 

However, the process of aging is highly individual. Yes, certain rules of thumb do apply, but overall, every dog has to taken into consideration as an individual. Two dogs even from the same litter may age completely differently! Years of stress, overexposure to environmental pollution, a low quality diet, lack of preventative veterinary care, athletic injuries, and genetic diseases can all negatively play into the aging process. So, how do you know when you should consider your dog to be a senior?

Aging can be so gradual (especially in otherwise healthy dogs) that it goes unnoticed until a more major issue presents itself. 

The most common signs (apart from age) that your dog may be nearing their senior years (or may be a senior!) are:

  • Changes in weight, especially an increase in weight
  • Loss of lean muscle mass
  • Build-up of plaque on the teeth or bad breath
  • Changes in bowel movement quality or frequency (consistently, not a one-off from eating something bad, for instance)
  • Changes in behavior including less enthusiasm for walks, more naps, or restlessness at night
  • Joint stiffness, hesitation to jump, or reduced activity
  • Reduced responsiveness to commands (may be a sign of hearing loss)
  • Changes in skin and coat texture and shine
  • Lumps and bumps appearing on the body, such as benign lipomas
  • Graying around the muzzle, eyes, and paws

It is important to recognize that working with a veterinarian becomes very important as your dog ages. This is because for senior dogs, there is a far greater chance that a disease may develop- osteoarthritis, kidney disease, heart disease, and cancer are all common in senior pets, and the chances of a dog developing these increase if the senior dog is obese. If your veterinarian recommends bloodwork and x-rays, I highly recommend having these diagnostics done- twice a year, if possible. By catching diseases early, you have a better chance at successfully treating or managing it. Preventative care can significantly extend your pet’s life!

What does this have to do with nutrition? Well, nutrition can be considered preventative (also called “proactive)” care as well, and this is where “feed the dog in front of you” really comes into play! The change from an adult maintenance diet to a supportive, proactive senior diet is encouraged due to changes in metabolic functions that can affect your dog’s energy requirements, macronutrient (fat, protein, and carbohydrate) digestibility, amino acid requirements, micronutrient requirements, immune system function, and level of oxidative damage.


As I mentioned, aging is highly individual and a switch doesn’t simply flip to “senior” when they hit the age shown in the chart above. However, proactive nutrition to best support your dog can definitely begin at the ages shown above. This is especially true for large and giant breeds, who tend to age faster and much more dramatically.

This is Jersey! She's a vibrant, happy girl who doesn't let that pesky senior status slow her down!


All dogs have nutritional requirements that include macronutrients (fats, proteins, carbohydrates) and micronutrients (vitamins, minerals). A large majority of fresh food feeders still follow ratio diets like BARF and PMR; these have been established for many years, are very popular online, and even have books about them detailing how best to approach the “rules” of feeding raw. They are also nutritionally incomplete and imbalanced, which means that while they should not be considered suitable for any dog, they are especially unsuitable in the life stages where our dogs need the most attention paid to their diet- puppies and seniors. If you are feeding a ratio diet and your dog is either established as being of senior age or you think that they might be approaching, your first step should be feeding a nutritionally complete and balanced diet. Some of the nutrients so often lacking in ratio diets- vitamin E, zinc, manganese, D3- are directly linked to age-related diseases like cancer as well as immunosenescence- that is, the natural deterioration of the immune system.  For some pet parents, this task feels monumental and thus it becomes faster and easier to work with a canine nutrition professional to create a diet plan for their dog that meets these nutritional guidelines.


Regardless of the life stage of your dog, it is always recommended to feed your dog by calories, and not feed by % of body weight. The latter option can vary hugely meal to meal when paired with a ratio diet that uses “variety” as its cornerstone. Senior dogs have a slower metabolic rate and many of them also become less active as they age, which further decreases their energy (caloric) requirement!


As the efficiency of the pancreas and liver naturally begin to decline, your senior dog may begin to have difficulties digesting protein or fat. This can manifest in several ways- mucus in the stool, loose stool, stomach gurgling, foul-smelling breath, vomiting, etc. If your senior dog is showing any of these symptoms or a combination of them, it’s probably time to reevaluate their diet. The diet of a senior dog can look quite different than that of an adult! It is important to note, however, that many senior dogs will continue to digest high fat and high protein diets without issue.


On the other end of the spectrum for energy requirement is the senior dog who begins to have the opposite issue- weight loss in the form of muscle wasting. Sarcopenia is the loss of lean body mass that occurs in the absence of any disease, but the presence of sarcopenia can then increase the likelihood of disease occurrence. Sarcopenia is a side effect of a natural change in the senior dog’s protein requirement- protein degradation and turnover rates increase while protein synthesis decreases. This protein requirement can increase by up to 50%!

While the majority of isolate amino acids (L-glutamine, L-arginine, BCAAs, etc.) are added for therapeutic purposes, adding additional taurine into the diet of the senior dog- especially if the dog is a breed or a breed mix that is genetically predisposed to cardiovascular disease- is a good idea. This can be added in powder form, such as NOW Taurine Powder, regardless of the type of diet your dog is eating.


When looking to create a diet for your senior dog, the micronutrients- the vitamins and minerals- should be reconsidered and some of them adjusted. This is especially true if your dog has been eating a ratio diet, where the phosphorus is often quite high but nutrients like manganese, zinc, and selenium are often quite low. Many of these cannot be balanced over time and for the optimal nutritional support of a senior dog, it’s best to provide all of their nutritional needs in full, every day.

Senior dogs often have increased urine output and so the vitamins and minerals that are excreted in the urine, such as most B vitamins, should be evaluated.

Omega fatty acids, especially the anti-inflammatory omega-3s EPA and DHA, become especially important to the senior dog. EPA is the fatty acid utilized by the body to decrease inflammation- think of joint health, or inflammatory responses in the organs- and DHA is the fatty acid required by the brain for cognitive health. Cognitive decline can be a serious concern for senior dogs, and providing ample DHA is very important.

For additional notes on micronutrients, please see my article The Sugar-Faced Years: Nutrition and Wellness for the Senior Canine.

For a thorough guide on omega fatty acids, please see my article Essential Fatty Acids: A Guide to Omega-6 and Omega-3 Fatty Acids for Dogs.


Here’s an excerpt from The Sugar-Faced Years: Nutrition and Wellness for the Senior Canine:

“Immunity declines with age which increases susceptibility to infection, likelihood of tumors, and, as cumulative antigen exposure in the gut increases, increases the likelihood of developing new intolerances to proteins that they could previously handle. Chronic antigen loads from proteins, infections, environmental allergens, etc. can lead to a chronic inflammatory status. Aging is thought to be associated with an increase in pro-inflammatory cytokines due a loss of cell to cell communication, elevated levels of which may be responsible for age-associated diseases with inflammatory aspects such as osteoarthritis, cancer, canine cognitive dysfunction, sarcopenia, and diabetes.  Senior dogs are known to have reduced CD4 T-cells- the cells meant to trigger a response to infections (so they become more prone to infections), while they can also show an increase is CD8+ T-cells (when can lead to an excessive immune response).”

Something that some raw feeding pet parents need to consider is the possibility of a cooked diet being the better option. If your senior dog is showing signs of a depressed immune system (things like repeated infections, increased susceptibility to yeast problems, and fevers); if your dog is on any medications that are immunosuppressants (prednisone is a common one); or if your dog has a condition that can affect their immune system (short bowel syndrome, history of a splenectomy, cancer, etc.) then switching from a raw to a gently cooked diet is always my recommendation. While it’s true that healthy dogs have stomach acid strong enough to handle the naturally heavy bacterial load of a raw meat diet, it’s generally not worth the risk for geriatric dogs and dogs with compromised immune systems. You can still feed a nutritious, wholesome diet to your dog using most of the same ingredients you are already using…just gently cooked!


Free radicals are reactive molecules that are naturally produced in cells and these play an important role in the aging process, and in the development of age-related diseases such as heart diseases, chronic kidney disease, and canine cognitive disorder. These can be sourced within the body (endogenously) or from outside of the body (exogenously) from things like air and water pollution, cleaning solvents, and everyday sources of radiation.

The older your dog is, the longer they have likely been exposed to exogenous sources of these reactive molecules and they’ve certainly been exposed to their own endogenous sources for longer! Aging and oxidative stress have a well-established link in dogs (and humans and other mammals) and this increased stress leads to a pro-inflammatory state that in turn affects the body’s homeostasis. This chronic oxidative stress and chronic, low-grade inflammation feed off of each other, increasing the likelihood of the development of age-related diseases.

Nutritionally, we combat oxidative stress by the inclusion of antioxidants into our dogs’ meals. The essential nutrients vitamin E and vitamin C are the most well-known by pet owners, but there are many, many other antioxidants that are not as prevalent and/or are not also considered essential nutrients, such as beta-carotene (vitamin A precursor), astaxanthin, and coenzyme Q10.

Hannibal, a very handsome Rhodesian Ridgeback, enjoying his therapeutic recipe.


While the purpose of this guide is to draw your attention to proactive considerations for seniors, sometimes we don’t have the luxury of more simple diet modifications and disease or illness is already present. In those cases, a therapeutic diet is likely required. Therapeutic diets will generally look quite different than the “typical” raw diet, as we are no longer dealing with an average dog! Heart disease, chronic kidney disease, liver disease, cancer, Cushing’s- common senior ailments like these require extra attention be given to their nutrition. I recommend working with a professional, whether that be an independent canine nutrition professional, a board-certified veterinary nutritionist, or a holistic veterinarian with training in nutrition.