Dog Diet: The Effects of Overfeeding and Underfeeding in dogs

November 4, 2021
Diana Bocco
Reviewed By: 
Dr. Farshad Goodarzi - Animal Nutritionist
5 minute read
dog looking at treat as dog diet

We are a nation of dog lovers and part of that love includes treating our dogs to what we think is great food. Because, after all, who doesn’t like a great yummy dinner?

The problem is that many people don’t really know what they’re feeding their beloved dogs. Too much food, the wrong kind of food, food that’s not properly balanced to help prevent disease and keep your pooch in optimal health. Some of us rely on commercial food to do the homework for us, others are feeding homemade or raw in hopes that it's healthy.

But without the proper knowledge of what your dog really needs, any type of food could lead to health issues and potential over or under-feeding.

According to VCA Hospitals, “obesity is the most common preventable disease in dogs.” Up to 30 percent of dogs are obese, which is more than the percentage of people who are obese in Canada (26.8%). The numbers are equally higher in the overweight category: 40-45% of dogs aged 5-11 years old are overweight while the Canadian humans fitting into that category reach 36.3%.

If you don’t find that telling enough, think about this: food-related illnesses and deaths are highly preventable. Because you’re in charge of your pup’s diet, it’s up to you to figure out the best foods for him to live longer, be healthier and be happier.

Over-Feeding Your Dogs

Canine obesity has become a major epidemic. The problem occurs after a chronic mismatch between the energy intake and energy requirements and it is characterized by increased energy retention, accumulation of fat and variable degrees of weight gain, from moderate to excessive. According to the AKC, over 50 percent of dogs are overweight or obese. But while other health issues would prompt most pet parents to head to the vet, obesity goes largely ignored. Interestingly, dog parents do not necessarily recognize overweight or obesity in their dogs. For many, it has actually become “normal” for dogs to be overweight.  The APOP (Association for Pet Obesity Prevention) calls this the ‘fat pet gap’ or a “misalignment between what we think a dog should look like and what a healthy body composition should really be.”

Of course, obesity is usually the direct result of overfeeding, whether that means too much regular food or too many treats. That’s because even people who might be feeding the right amount of calories through food might not be accounting for the extra calories treats provide. Treats should not make up more than 10% of the calories in your dog’s diet – if you train regularly and need to use treats, you might need to adjust the amount of food you feed.

The problem of obesity is more obvious in older pets, however, considerable variations exist depending on breed, sex, individual endogenous and environmental factors. The level of body fat can vary extensively between breeds. As a rule of thumb, 10% overweight can be considered as beginning obesity, 20% are indicating the manifestation of severe obesity. Body fat concentrations, being 10-20% in normal-weight dogs can rise up to 40% in obese individuals.

Overfeeding can lead to serious issues, as overweight dogs are more likely to develop diabetes, arthritis and other inflammatory conditions. Plus, excess weight makes it difficult for dogs to move well, which means they’ll exercise less and when they do move, they’re more prone to injuries.

Experts point out that too much food might seem like an act of love, but it’s actually harming your dog. In fact, a recent study that followed more than 50,000 dogs for over 20 years, tracking their weight and health to see the impact of weight on dogs’ lifespan, proved just that. The results clearly showed that dogs that maintained a healthy weight range lived up to 2.5 years longer than those qualified as overweight.

two different dog diet food labels from two different brands

Overcoming the Mystery of Labelling

Pet food labels allow assessment of the nutrient composition, however, the information given by the label may be misleading to consumers. The principles of labelling are regulated by the AAFCO in North America and European Regulation (EC) No 767/2009 in the EU. All nutrients have to be listed according to those legal requirements. The concentrations are always related to the feed “as is” or in other words to the “original” material. This makes a comparison of nutrient densities more difficult between different types of pet food. If a dry diet for dogs would be labelled to contain 15% of crude fat, and an alternative canned food would be labelled to contain 8% of crude fat, it is often not clear to consumers, that the latter diet has a higher fat concentration, related to its dry matter, compared to the dry diet. The level of fat in the dry matter of a wet diet can be calculated easily. Assuming that the labelled moisture content of the wet diet is 80%, the dry matter content of the diet would be calculated by 100% - 80% = 20%. The concentration of fat in the dry matter can be calculated by dividing the labelled fat concentration (as is) by the dry matter content and multiplication by the factor 100:

  • 8% (fat content as is) ÷ 20% (dry matter content) × 100 = 40% (crude fat in dry matter).

This example shows how often you can be misled about this essential basic information about the nutrient profiles of the diet which you use.

Another factor that you would have to consider is “the amount of nutrients your dog gets per day”. For instance, when you feed your dog with 105 g/day of a kibble product with 90% dry matter and 15% crude fat (as is) the amount of fat he receives per day is 15.78 g:

  • 15% (fat content as is) ÷ 90% (dry matter content) × 100 = 16.7% (crude fat in dry matter).
  • 105 (g amount of food per day) × 90% (dry matter content) = 94.5 (g dry matter food per day)
  • 16.7% (crude fat in dry matter) × 94.5 (g dry matter food per day) = 15.78 (g fat per day)

You’re not sure if you’re overfeeding your dog? Figuring that out based on weight alone can be tricky, especially for mixed dogs where you don’t have an average weight for the breed to rely on.

A simple check is to look at your dog from above. If you see an hourglass shape, chances are your dog is the right weight. Using your hands, you should also be able to easily feel their ribs and spine. You can also use the dry matter calculator from Omni to calculate the dry matter accurately.

Overfeeding Isn’t Just About Weight Gain

If your dog doesn’t seem overweight, you might think all’s good with what you’re feeding, but this isn’t necessarily the truth. Sometimes the pounds pack on slowly so you might not notice the weight gain, especially on large dogs. But even if your dog isn’t necessarily getting chubbier, overnutrition can also lead to other health problems.

Bowel Issues: Abdominal discomfort, gas, and loose stools can all be connected to eating too much. The digestive system simply cannot work effectively if it’s constantly being overworked.

Skin Problems: Persistent shedding isn’t normal in most dogs and it could indicate a problem with nutrition. The same is true of constant itchiness. In the absence of parasites like fleas, a dog who’s always scratching probably has an underlying condition causing it – and those conditions are often connected to nutrition. Some dogs might be allergic to some of the ingredients in the food you’re feeding, while others might not be getting the right nutrients or even eating too much. Certain nutrients negatively interact with one another and have detrimental effects on the bioavailability of each other. For instance, besides the fact that excessive amounts of calcium or phosphorus can negatively affect absorption and utilization of each other, the antagonistic effects of calcium are also detrimental for iron, manganese, copper and especially zinc. Indeed, the iron, zinc, manganese and copper requirements of a dog increase when he receives a meal containing high levels of calcium. Zinc, iron, manganese, copper and selenium are essential trace elements. In dogs, the role of zinc in skin health has been well documented. Like zinc, copper and selenium are particularly important for the skin, hair, immune system and reproduction. Given the known negative interactions between certain nutrients which affect their bioavailability, all the nutrients in the final food mixture must be provided in a proper manner, with the right proportions and ratios. These include but are not limited to:

  1. Energy to protein ratio,
  2. Calcium to phosphorus ratio,
  3. Amount of calcium and trace elements

Joint Problems: Overweight dogs often experience pain and discomfort in their joints. In fact, according to VCA Hospitals, “being overweight and obese set the stage for increased risk of joint damage and subsequent osteoarthritis (OA), leading to chronic pain.” And if you thought OA was just about age, you’d be wrong – at least 20% of all dogs show evidence of OA, including younger dogs. The constant wear and tear caused by excess weight traumatizes the joints over time and leads to inflammation and pain, which in turn leads to arthritis. This is often worse on dogs that are fed a poor-quality diet lacking in Omega 3 and 6 fatty acids.

Lethargy and Tiredness: Being overweight takes a toll on your body and the same is true for our canine friends. But even overfed dogs that aren’t overweight can also feel tired and not up for running and playing around. This could be because they feel too full to move too much or because their joints or tummy might be in pain. Changes in behavior and energy levels should always be discussed with a veterinarian, as they could also be signs of a number of underlying health issues.

Under-Feeding Your Dog

Underfeeding your dog on purpose is a form of animal abuse. In fact, the Humane Society considers underfeeding “intentional cruelty” – just as bad as depriving your dog of water, shelter or veterinary care.

While we don’t expect our readers to intentionally deprive their dogs of food, you might be surprised to know that you could be accidentally underfeeding your dog. In fact, this is more common than you might think in multiple-dog households unless you’re closely watching your dogs when they’re eating. For example, a weaker or smaller dog might get bullied by other dogs and have food stolen from him. Or if you free-feed, the bigger dogs might get to eat most of it, leaving little for the other dogs.

You might also be under-feeding by accident if you’re not measuring the amount properly. For example, if you’re just guessing the amount or using a cup (and probably not the same one) every day to feed. When in doubt, a proper measuring tool is a key to getting the proportions just right.

Underfeeding can also happen when using commercial dog foods because the feeding guide listed on the package is normally a wide general range and doesn’t take into consideration your dog’s lifestyle and personal needs. For example, active and working dog breeds might not get enough nutrition from a standard feed. Not only do they need an adjustment in the nutrients they consume, but they might also need to be fed just a little bit more than what the charts recommend.

Underfeeding or feeding poor quality food that’s not meeting your dog’s nutritional needs could also lead to malnutrition. While the most common sign of underfeeding is weight loss, dogs that aren’t getting proper nutrition can also show other signs of malnutrition, including:

  • Tummy troubles: A change in the color or consistency of your dog’s feces can indicate the bowel isn’t very healthy. An unhealthy gut biome can be the result of many things, but feeding a nutritionally poor diet is certainly part of it. To learn more about your pups number two habits please refer to our blog “A Super Guide to Your Dog's Poop: Frequency, Color, State, Smell & More
  • Lack of energy: Lethargy can be a sign of illness, especially if coupled with depression or a down mood. But it can also be a sign that your dog is not getting the proper nutrition to keep him healthy and strong.
  • Skin & Coat issues: Loss of hair, a scruffy coat or dry skin can all be signs of underfeeding as well. When you’re not providing proper nutrition, what little the dog consumes will go to more biologically important functions in the body, such as keeping the organs running properly. If there’s nothing left nutritionally to nourish the skin and coat, this is where you’ll see issues first.
  • Weak immune system: Nutrition is a critical factor for a well-operating immune system. Many nutrients have been identified as essential for the development, maintenance and function of the immune system, including amino acids, vitamins like C, D, E, minerals like selenium, iron, zinc, and more. Deficiency in these nutrients can make the immune system of your dog vulnerable.

Still unsure if you’re feeding too much or too little? This body condition score chart can help you better understand how well your dog is doing and whether you need to adjust his food intake.

Chart showing ideal dog shape with description
We recommend switching to fresh dog food over a 7-day period

The Connection Between Nutrition and Illness

You already know that poor nutrition can exist regardless of whether you’re overfeeding or underfeeding. You also know that obesity is connected to a number of health issues and so is not feeding enough nutrients.

But poor nutrition can also lead to reduced immunity. When your dog’s body doesn’t get the nutrition it needs, it becomes more vulnerable to infection, allergies and problems with healing. This is even worse if your dog already has a food allergy, as this can take a toll on the immune system and trigger worse issues, including environmental allergies.

An even scarier consequence of poor feeding is pancreatitis. This is a serious inflammation of the pancreas and can be life-threatening. Pancreatitis inflammation can be triggered by high-fat foods, obesity, food allergies and some toxins, a high-fat diet being the most common one. It means that it’s not only commercial food that can lead to this problem. Overfeeding a homemade diet can be just as damaging if you’re feeding too much or feeding the wrong combination of ingredients. If you’re going to walk away from commercial food (and you should!), you need a well-balanced diet to ensure proper nutrition but also to make sure the calorie count and fat content are just right.

Calcium and phosphorous are the "bricks" (the building foundation) of the bones. Nutritional imbalances, particularly deficiencies or imbalances of calcium, phosphorus, and vitamin D in your dog's diet, can lead to bone disorders. These, in turn, cause serious and permanent problems, especially in young dogs.

Dog standing beside Cola's Kitchen Fresh Dog Food Box And Packages

Addressing the Feeding Problem

Both overfeeding and under-feeding your dog can lead to a whole host of health issues. Combine that with a poor-quality diet and you can end up with a dog that seems to be eating well but it’s still not in great condition.

To prevent long-lasting problems, you should feed your dogs a high-quality, wholesome diet that’s free from preservatives and additives.

Unfortunately, just because a commercial dog food is labelled as “complete and balanced” doesn’t mean your dog is receiving optimal nutrition. Experts agree that ingredients such as corn, wheat, soy, additives and preservatives, salt and “meat” (without specifying which kind) provide questionable nutrition and are often only used as ingredients because they’re cheap.

Learning to read ingredient labels on dog foods is a great first step, but that still doesn’t guarantee that what you’re buying is the best option for your dog since there’s no personalization. A two-year-old dog who likes to run around needs a very different combination of nutrients than a seven-year-old who rather naps in the sun.

Looking at the feeding chart on commercial dog food containers doesn’t tell you much. Their one-size-fits-all chart doesn’t account for a dog’s particular needs, so you can never really tell if you’re feeding what your dog really needs.

In addition, for a diet to be healthy, it needs to be not only the right amount but also well-balanced and appropriate for the age, breed, weight, activity, biological and health status of your dog. An athletic dog shouldn’t eat the same as a dog who’s happier lounging on the sofa -- no matter if they’re the same breed, age and weight.

Feeding an individually balanced diet doesn’t have to be complicated. Take a 5-minute quiz and Cola's Kitchen will build the right diet to help your pup thrive.

Does your dog have allergies or special needs? We’ll account for that too when designing the right combination of ingredients and nutrients. We’ll even account for extra activity, age and other variants that affect how much and what your dog needs. In short, we offer completely balanced daily meals delivered right to your door so you never have to do any guesswork when it comes to feeding your pooch right.

about cola's precision diet

Cola's Kitchen precision diet is the first truly tailored diet for a unique approach to nutrition. Our diets are individually formulated and balanced to address the most precise nutritional requirements of your pup.

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