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Featuring Demian Dressler, DVM and Sue Ettinger, DVM, Dip. ACVIM (Oncology), authors of The Dog Cancer Survival Guide

Are Overweight Dogs at a Higher Risk for Cancer?

Updated: May 5th, 2021


Are overweight dogs at a higher risk for cancer? Yes. It turns out that being chubby isn’t nearly as cute as we once thought.

When a dog is overweight, they’re usually thought of as being cute and cuddly. The thought of the dog being less healthy is not a common thought in our minds. The fact is that overweight dogs are at higher risk for conditions like cancer and diabetes.

Think about it- when we walk into a home and see a chubby Corgi waddling her body adorably around the house, our first reaction is… what? “Oh my goodness, look how adorable she is!”

We don’t think about how being overweight is damaging her health. But, scientists have uncovered a potential link between obesity and dogs with cancer.

Keep in mind, I am simply sharing this information. I’m not a veterinarian, although I am a behavioral expert. But Dr. Dressler, who IS a veterinarian, wrote overweight dogs in Chapter 14 of The Dog Cancer Survival Guide.

First and foremost, let’s find out if our dogs are overweight or not.

Is My Dog Obese?

Your veterinarian should be consulted if you’re unsure what your dog’s body should look like. Depending on the breed of your dog, it could be hard to tell. But, to give you an idea, you can take a look at a body condition score chart.

The body condition score chart will help you to estimate if your dog is underweight, just right, or overweight. Most of the time, you can tell by taking a look at the following information:

  • Underweight: You’re able to see your dog’s ribs, vertebrae, pelvic bones and/or other bones from a distance. You don’t see much muscle or fat.
  • Just right: You can feel the ribs, but there is some fat covering them. You’re able to see your dog’s waist from above. And, their abdomen is tucked up when you view your dog from the side.
  • Overweight: There are different stages, but if your dog is significantly overweight, there will be too much fat covering the ribs to feel them. There will be a lot of fat near the base of their tail. You won’t be able to see your dog’s waist from above. And, their abdomen won’t be tucked when you view your dog from the side.

Obviously, your super-fluffy dog might not show you their shape easily. So take a look next time you give your dog a bath!

AVMA Study: Potential Link Between Obesity and Dog Cancer

There are many studies about cancer and obesity. But, I chose this one to share with you because it’s published with the AVMA (American Veterinary Medical Association). A group of veterinarians was curious to find out if there was any link between dogs who were overweight and the development of cancer. The researchers looked at a large sample of veterinary records. 1,777 dogs had cancer, and 12,893 dogs did not.

The researcher’s goal in the study was to find out if there were a larger percentage of dogs with cancer who were obese… or if the dogs with normal weight had the same risk of developing cancer as the overweight dogs.

Their findings were what they expected. The study found obesity could potentially be linked to a few different cancer types in dogs– urinary cancer and mammary cancer.

Why Obesity is Connected to Dog Cancer

In his book, Dr. Dressler points out that we aren’t 100% certain WHY obesity might cause cancer. But we may have a clue in new research that has shown fat cells secrete a substance called adiponectin.

This is important because it turns out that adiponectin is protective for cancer. It blocks the development of cancer cells.

So, more fat cells, more adiponectin, less cancer right? Nope!

Instead, studies with rodents and humans show less adiponectin is secreted when there is too much fat stored in the body.

The opposite is also true: more adiponectin is secreted when fat is being used to fuel the body, as it does in dogs with lean bodies.

This means that dogs who are more fit and are burning fat for fuel may be less likely to develop cancer than dogs who are holding on to too much fat.

In short: overweight dogs are at higher risk for cancer.

So … How Much Should I Feed My Dog?

This is a hard question to answer, because when it comes to diet it’s not ‘one size fits all.’

You can search high and low for specifics on how much to feed your dog to keep her or him fit, but never find any. The truly aren’t any guidelines that are applicable to all dogs.

How much to feed a dog is dependent on way too many variables to make anything other than the most general guidelines.

As Dr. Dressler writes in The Dog Cancer Survival Guide, the same amount of food that feeds an energetic 50-pound dog for two days might feed a 50-pound couch potato for four days.

If you think about this in human terms it will help. Extreme athletes — marathoners, Ironman competitors, gymnasts — may need to take in as many as 12,000 calories in a day in order to stay fueled. And some have to consume more.

But most of us expend much, much less energy than those super-humans. Most of us only need 2,000-2,500 calories per day.

Also, women typically need fewer calories per day than men do (in general) because they have a higher percentage of body fat and a lower percentage of muscle. Muscle burns more calories than fat — so a more muscular person needs more fuel.

Fluctuations in hormones in both sexes, environmental factors (heat, cold, etc.) and many other variables also come into play. There’s no authority who can say “everyone should eat X amount of food, in Y weight” for humans, and there isn’t such a rule for dogs, either.

So, Again: How Much Should I Feed My Dog?

As Dr. D points out in chapter 14 or in the special report, dog cancer diet, the master recipe he recommends is a guideline. It’s difficult to predict volume because each time you make the food, it could be different.

For example, some meats are denser than others, so a pound of one protein might take up less volume than a pound of another. Same with veggies. Depending upon what you are using, you might get more or less food by volume.

So. What to do when we radically re-formulate our dog’s diet as suggested by Dr. Dressler?

We experiment and see what works for OUR own unique dog.

For example, at first, your dog may only want/need a cup of food per meal (we don’t know how large your dog is, so this is all hypothetical). If he starts to feel better, perhaps he moves around more, and wants and needs more — and suddenly, you realize a cup and a half is the right amount. That’s OK — because there is NO one rule.

For your dog, we suggest starting by asking yourself how much energy he/she is expending in general.

On a scale of couch potato to athlete, where does he or she fall?

If she’s all the way over on athlete, give half of the amount of food that recipe makes one day, and the other half the next.

If she’s a couch potato, give 1/4 the recipe over four days.

If she’s in between, maybe give 1/3 of the recipe over three days.

Then, proceed from there.

If You’re Concerned About Your Dog’s Weight

If you really want cups and ounces to guide you, your veterinarian may be able to help you determine for your dog’s case what condition he or she is in, and therefore a rough guideline about how much to feed.

However, in our experience over the years, many vets are well aware of the limits of their education as regards nutrition. After all, most vet schools “teach” this subject by bringing in pet food industry professionals to give those lectures! Most vets will refer out to a nutritionist in order to get you the kind of answers you’re asking for.

If you’re interested in consulting with a veterinary nutritionist yourself, you can find the directory on AVCN here.

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