Why Is My Dog Getting Fat?

Welcome to Why Is My Dog Getting Fat?, the 4th and final installment of the 4-part Dog Weight Loss Guide. After learning the causes of weight gain in dogs, continue along the journey to the first step in helping your dog’s obesity, diet:

Dog weight loss guide journey:

Why Is My Dog Getting Fat?

If only our dogs could talk. Even a simple “I’m stuffed!” after dinner would help identify if we need to decrease their portion size. More importantly, our dogs could tell us if something feels wrong, and it’s not the food. 

Thankfully, the answer to “why is my dog getting fat?” is often overeating and lack of exercise. But there are other factors potentially influencing your dog’s weight, including:

  • Age
  • Genetics
  • Medical conditions
  • Neutering

Like people, if dogs consume more calories than they burn, the excess calories are stored as fat. But, even on the strictest diet, weight gain and obesity can be caused by underlying health conditions.

This article details the many causes of dog weight gain to help you identify the potential culprit. By the end, you’ll have a better picture of your dog’s health concerns and a plan of action going forward.

  1. Why is my dog gaining weight?
  2. How to identify if your dog is overeating.
  3. Why is my dog gaining weight but not eating more?
  4. How does a dog’s breed affect its weight?
  5. Why does my dog have a sudden increase in appetite?
  6. Maintaining your dog’s healthy weight.
Why is my dog getting fat? A bulldog sleeps with a tape measure across his body.

Why is my dog gaining weight?

As you begin your dog’s weight loss journey, understand you’re not alone. In a survey by the Pet Obesity Prevention Organization, 56% of dogs in the United States are overweight or obese. Even 80% of veterinarians have admitted to helping their own pets lose weight.

Obesity is the most preventable disease plaguing our dogs. And it’s the leading cause of death in dogs. 

So, why is your dog gaining weight? In most cases, the cause of a dog’s weight gain is overeating or lack of exercise. Like people, if dogs consume more calories than they burn, the excess calories will be stored as fat.

Diet may be the primary factor influencing your dog’s weight, but age and breed make an impact too. Active dog breeds require high levels of exercise, while some breeds’ genetics naturally place them at increased risk of obesity and health conditions.

Dog weight gain after neutering is also common. When neutered, a dog no longer produces testosterone, causing a hormonal imbalance. This imbalance can slow the metabolism, decreasing their need for calories.

Hypothyroidism and Cushing’s disease are two conditions that affect the metabolism in dogs, leading to weight gain. 

When narrowing down why your dog is getting fat, start with what’s controllable at home, food and exercise. 

How to identify if your dog is overeating.

To identify if your dog is consuming too many calories, start by counting your dog’s daily caloric intake. Dog food manufacturers are required to list the calories in standard household units, usually kcal/8 oz cup.

Work through your regular daily routine with no changes — including any human foods, dog snacks, or supplements you regularly give your dog.

Once you determine your dog’s average daily caloric intake, reference it against a dog calorie calculator to determine if your dog is consuming too many calories.

If you discover your dog is exceeding their daily suggested calories, you have a clear path to reducing your dog’s weight; more exercise or fewer calories.

Your next steps to start your dog on a path to weight loss will be:

  1. Weekly weigh-ins to track progress.
  2. Stopping or switching all snacks to healthy fruits and vegetables.
  3. Reducing the serving size of their regular meals.
  4. Making gradual adjustments until you reach a healthy 1% to 1.5% decline in body weight each week.

If you determine calories and exercise are not the cause, it’s time to explore more potential influences.

Why is my dog gaining weight but not eating more?

Once you’ve determined overeating and lack of exercise are not influencing your dog’s weight gain, you must consider age, genetics, and medical conditions.

As dogs reach their senior years, weight gain becomes more common. Dogs struggle to maintain a healthy weight when they reach 6 to 10 years of age.

With a slowing metabolism, our greying senior dogs become more content with lounging. But, senior dogs still require a minimum of 30-minutes of exercise daily, including walks and playtime.

Genetics and medical conditions can cause weight gain in dogs.

When your puppy, adult, or active senior dog is gaining weight, the cause can be genetics or a medical condition.

A dog’s breed is one of the most significant factors impacting its weight. Researching your dog’s breed can answer most questions about their weight, exercise needs, and health concerns.

Dog breeds prone to weight gain include:

  • Cocker Spaniel
  • Beagle
  • Labrador Retriever
  • Golden Retriever
  • Shetland Sheepdog
  • Rottweiler
  • Mixed breed dog
How does a dog's breed affect its weight? Various dog breeds sitting in a meadow.

How does a dog’s breed affect its weight?

Each dog was bred for a specific purpose, often separating them into their respective groups. Understanding the role of your dog’s breed can better help you determine their exercise needs.

  • Herding Group: These dog breeds were bred to herd animals all day. They have an incredible amount of stamina and need to be able to run for long periods. Examples: Australian Cattle Dog, Australian Shepherd, Bearded Collie, Border Collie, Beauceron.
  • Terrier and Sporting Groups: Bred to hunt and retrieve animals like birds or rabbits, these dogs need quick bursts of energy to help them chase down their prey. Examples: American Foxhound, German Shepherd, Golden Retriever, Irish Setter, Jack Russell Terrier, Labrador Retriever, Rhodesian Ridgeback, Weimaraner.
  • Hound Group: Bred to track down animals by scent, hound dogs need to be able to run for long periods and have a ton of energy. Examples: Basset Hound, Beagle, Bloodhound, Greyhound, Petite Basset Griffon Vendeen
  • Working Group: Bred for large jobs like pulling carts, guarding property, or rescuing people, large working dog breeds require extra exercise to stay healthy and happy. Examples: Great Dane, Bernese Mountain Dog, Doberman Pinscher, Boxer, Siberian Husky, St. Bernard

Groups like Toys or non-sporting dogs were bred as companions, often with no designated job, allowing them to get by with a calm, less active lifestyle.

Exercise aside, many breeds are susceptible to health conditions, diseases, and genetic defects which affect mobility and appetite, leading to weight gain.

Labrador and Golden Retrievers suffer from a gene deletion mutation of POMC — a gene responsible for regulating appetite. The gene deletion makes Labs and Goldens prone to over-eating. 

According to the Association for Pet Obesity Prevention, 63% of Golden Retrievers are overweight or obese.

Hypothyroidism can be the culprit if you notice your dog gaining weight without an increase in appetite. Often diagnosed between the ages of 4 and 10, hypothyroidism affects the thyroid gland, a small, butterfly-shaped gland in the neck responsible for regulating metabolism and other essential body functions.

Dogs with the highest risk of developing hypothyroidism are:

  • Golden Retrievers
  • Dachshunds
  • Cocker Spaniels
  • Labrador Retrievers
  • Doberman Pinschers
  • Boxers
  • Irish Setters
  • Miniature Schnauzers

A serious condition, hypothyroidism can be treated but not cured.

Why does my dog have a sudden increase in appetite?

A sudden increase in appetite is one of the symptoms of Cushing’s disease, a rare but severe disease in dogs that produces excessive cortisol levels. Cortisol is a hormone released by the adrenal gland when stressed.

When noticing an increased appetite, look for the following symptoms common in dogs with Cushing’s disease:

  • Excessive water consumption and urination
  • Hair loss
  • Excessive panting
  • Thinning of the skin
  • Abdominal enlargement
  • Calcified skin lumps (Calcinosis cutis)

Thankfully, only 3% of dogs suffer from Hypothyroidism, and less than 1% have Cushing’s disease. However, If your dog is a high-risk breed — like Golden Retrievers, with 25% suffering from Hypothyroidism — it’s vital to watch for signs. 

maintaining your dogs weight. A jack russell terrier running across the grass with a carrot in its mouth.

Maintaining your dog’s healthy weight.

Obesity is the leading cause of death in dogs. A study by the Journal of Veterinary Internal Medicine showed obesity in dogs can shorten their lifespan by two and a half years.

Furthermore, obese dogs are 2.6x more likely to be diagnosed with diabetes, while 34% of obese dogs have oral disease. 

Several diseases and conditions are linked to obesity in dogs, including:

  1. Osteoarthritis
  2. Diabetes
  3. Oral disease
  4. Heart disease
  5. High blood pressure
  6. Kidney disease
  7. Cancer
  8. Liver disease

How can you maintain a healthy weight for your dog? 

The key to a long healthy life in dogs starts with diet and exercise.

Feeding tips:

  • Slow down your dog’s eating by serving in two portions, or use a slow feeder dog bowl to help them feel full and better digest their food.
  • In multi-dog households, feed your dogs separately.
  • Split meals into small portions and feed with more frequency.
  • Use a measuring cup for every meal.
  • Make sure your dog has fresh water at all times.

Do not:

  • Give your dog scraps of human food.
  • Use a self-feeder.

How much exercise should your dog get?

Daily exercise is vital for all dogs. Regardless of age and size, dogs need at least 30-minutes of exercise each day, with more active dog breeds requiring an hour or more. As a general rule,

  • Puppies need 5 minutes of exercise twice daily for each month of age. Playtime and short, structured walks should be part of the daily routine.
  • Adult dogs need a minimum of one hour of exercise each day. It would be best if you exercised at least twice a day. More playtime in between will make your pup even happier.
  • Senior dogs still need 30 minutes of exercise each day—unless instructed otherwise by a veterinarian.

Aside from diabetes and other dangerous conditions, weight gain in dogs can cause joint problems, overheating, and breathing difficulties.

Final Thoughts. 

If you determine food is not the cause of your dog’s obesity, schedule an appointment with your veterinarian immediately to run a physical and blood panel. Your vet can eliminate the possibility of severe diseases and help identify the cause.

If you aren’t already, start walking your dog daily and have playtime twice daily, once in the morning and then at night. 

Since fetch and tug-of-war aren’t for every dog, consider other fun activities, like:

  • Swimming
  • Hiding a strong-smelling, low-calorie treat to work a scent trail
  • Purchase a treat dispenser toy
  • Play tag or chase
  • Set up an obstacle course with furniture
  • Play hide-and-seek

A healthy weight in dogs is the key to a long, healthy life. Daily exercise and diet are the only way to achieve it.

Is your weather nice today? Go for a walk. Your pup will thank you.

Just finding this page? The 4-part dog weight loss guide starts with the article below.
Is My Dog Fat? A Guide For Dog Weight Loss.
Is my dog fat?

Obesity affects 56% of dogs in the U.S. Learn how to identify weight gain and obesity in your dog, so you can take the next step in curing it

Frequently Asked Questions

What causes rapid weight gain in dogs? 

If your dog is experiencing rapid weight gain, it’s likely a sign of a serious health condition. Rapid weight gain can happen in dogs with Cushing’s disease and hypothyroidism. Both conditions impact a dog’s metabolism since they directly influence hormones.

Why is my dog getting fat for no reason?

Like humans, dog’s never gain weight for no reason. If eating and exercise habits have remained consistent, your dog’s age or an underlying health condition may be causing the weight gain. Consider blood work and a physical with your veterinarian.

How do I reduce fat in my dog? 

You can reduce fat in dogs through diet and exercise. A dog’s healthy weight loss goal is 1% to 1.5% of body weight weekly.

Begin by gradually decreasing their calorie intake and reducing snacks to none or healthy options, like fruits and vegetables.

Start with daily walks and playtime twice a day. If your dog has been primarily inactive, start slowly and increase the walking pace or distance as their conditioning improves.

Weekly weigh-ins are essential to keep track of your success.

Do dogs get fatter with age?

Senior dogs are more prone to weight gain. Usually, between the age of 6 to 10, a dog’s metabolism and energy levels begin to decrease. Even as your dog ages, keeping a regular exercise routine is essential — while putting less impact on their joints. 

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