Dog Losing Weight But Eating Well? Causes & Solutions

If your dog is losing weight but eating well, it can be confusing and a little alarming. The good news? There can be answers that don’t require medication. Many cases can be managed with the right nutritional care.

Let’s break down what might be going on, and what you can do to help your pup stay happy and healthy.

Why Is My Dog Losing Weight?

If you’re wondering, Why is my dog losing weight, you’re not alone. Sudden or unexplained weight loss can happen for many reasons, some harmless, others serious.

Dogs, like humans, can drop pounds due to age, diet, or changes in metabolism. But when the weight loss is noticeable, especially if they’re still eating normally, it’s worth paying attention to.

Here’s the critical point, weight loss is often a symptom of a condition, not a disease in itself.

Let’s explore some potential culprits below.

Digestive Disorders

Digestive problems can cause your dog to absorb fewer nutrients from their food. Even though they’re eating the same amount, or more, they might not be getting what they need.

Common issues include:

• Inflammatory bowel disease (IBD)
• Food allergies or intolerances
• Pancreatic enzyme deficiencies

When these systems go awry, your dog’s body starts to “steal” fuel from fat and muscle reserves, leading to weight loss.

An older dog losing weight is especially prone to these issues. Keep an eye out for loose stools, frequent vomiting, or a bloated belly.

Common Digestive Issues Table

If you suspect a digestive issue, a vet visit and some lab work will usually get to the bottom of it.

Underlying Medical Conditions

Sometimes, dogs losing weight are dealing with something deeper. Medical conditions like diabetes, kidney disease, or hyperthyroidism can cause unexplained weight loss.

For example:

• Diabetes causes sugar to be excreted rather than used for energy.
• Chronic kidney disease impacts nutrient retention.
• Hyperthyroidism (though rare in dogs) boosts metabolism excessively.

Your senior dog losing weight might be silently battling one of these. These issues often don’t show up until they’re more advanced, so regular checkups are important.

Bloodwork can often catch these before they get serious. And guess what? Many conditions can be managed with meds and diet changes.

Age-Related Muscle Loss

If you’ve got an elderly dog losing weight, the cause might be simple muscle wasting, also known as sarcopenia. As dogs age, their activity levels often drop, and so does their muscle mass.

But it’s not always “just old age.”

You’ll want to rule out other health problems first.

Still, adding higher-quality proteins and light resistance can slow down age-related loss.
This is especially common in older dogs losing weight but acting normal; everything seems fine except for the shrinking frame.

Poor Nutrition or Caloric Mismatch

Even if your dog is eating well, the type of food matters. Not all calories are created equal.
Affordable dog food may be high in fillers and low in nutrients. If your dog’s energy needs aren’t being met, especially for active breeds, they’ll start burning reserves.

Also, the average weight of dogs varies widely by breed. A 70-pound lab and a 10-pound terrier don’t have the same needs.

If you’re unsure whether your pup is getting enough, talk to your vet about their ideal weight range and caloric needs. There are great feeding calculators online, too.

Dental Problems

Some dogs with dental pain will keep eating, just more carefully.

They might swallow food whole, avoid harder kibble, or eat more slowly. Over time, poor chewing leads to reduced digestion and, eventually, weight loss.

Check for:

• Bad breath
• Drooling
• Pawing at the mouth
• Bleeding gums

If your dog is losing weight but eating, and they’re older, dental issues should be on your radar. A dental cleaning (or a few extractions) can work fine.

Stress or Behavioral Changes

Just like people, dogs can lose weight from emotional or environmental stress. New home? Loud noises? Loss of a companion?

Stress hormones can alter appetite, digestion, and sometimes metabolism.

This is especially true for rescue pups or when there’s been a big life change.

Look out for:

• Pacing or restlessness
• Whining or hiding
• Changes in sleeping patterns

These dogs might still eat, but anxiety can burn extra energy or mess with how nutrients are absorbed. If your dog losing weight but acting normal, stress might be the main reason.

Serious Illness

Nobody wants to think about this one. But unexplained weight loss can sometimes be the earliest clue of serious weight loss.

In particular, gastrointestinal tumors or systemic cancers can:

• Affect appetite subtly
• Impair digestion
• Cause chronic inflammation

Weight loss from serious conditions is usually progressive and may be accompanied by lethargy, vomiting, or swelling.

If you’ve ruled out all other options, or your dog is losing weight but eating, ask your vet about imaging. Better to know than wonder.

You can also read: Best Practices for Weight Gain in Dogs

What to Do Next: When to See a Vet

If your dog has lost more than 10% of their body weight over a few weeks or continues losing weight despite eating well, it’s time for a vet visit.

Bring notes on:

• When the weight loss started
• Any changes in food, environment, or activity
• Stool and energy levels
• Any new symptoms (coughing, limping, etc.)

Early intervention can make all the difference.

You can also explore: Immunovet Total Immune Support for Dogs

Tips to Help Your Dog Maintain a Healthy Weight

Once you’ve identified the cause, here are some helpful strategies to keep your dog at their ideal weight:

Top 5 Healthy Weight Strategies for Dogs

1. Upgrade their food – Choose nutrient-dense, vet-recommended brands.
2. Add a topper – Bone broth or meat-based toppers boost calories.
3. Introduce light exercise – Even senior dogs benefit from movement.
4. Regular weigh-ins – Track progress monthly at home or the vet.
5. Routine bloodwork – Especially for senior dogs or those on meds.

Ready to Learn More?

Helping your dog maintain a healthy weight is one of the best gifts you can give them—it supports their energy, longevity, and overall well-being.

At MyImmunovet store, we’re dedicated to providing supplements and resources that keep your furry friend strong and healthy at every stage of life.

Discover more with MyImmunovet and take the next step in your dog’s wellness journey today.

You can also explore: Immunovet Blog for Knowledge & More

People Also Ask:

Why senior dog losing weight but still eating?

It may be due to muscle loss, poor nutrient absorption, or health issues like diabetes, kidney disease, or cancer. A vet check is essential.

What is the average weight of a dog in kg?

Dog weight varies: Toy 2–5 kg, Small 5–10 kg, Medium 10–25 kg, Large 25–45 kg, Giant 45+ kg. Always confirm with your vet for your dog’s ideal weight.

How to help the dog gain weight?

Offer high-calorie, nutrient-rich meals, add healthy toppers, feed smaller frequent meals, and use high-protein foods. Always rule out illness with a vet first.