Weight loss is one of the potentially quiet symptoms that I find quite scary.
If your dog has been overweight, you are likely to welcome that the pounds are coming off. But unless it’s happening because you’re taking deliberate steps such as changes in lifestyle and diet, do take note.
Further, things might overlap. Just because you’re trying to get your dog to thin out, it doesn’t always mean that’s why it’s happening. Read Beaner’s story to learn how complicated things can get.
Potential causes of abnormal weight loss in your dog include:
- poor diet
- intestinal parasites
- GI disease
- Addison’s disease
- kidney disease
- liver disease
- heart disease
The big picture
Considering the big picture, take a look at the following:
- how much weight has your dog lost and how rapidly
- were there any dramatic changes in your dog’s exercise, lifestyle, and diet
- is your dog hungry or refusing to eat
- are there any other symptoms
Should you be freaking out? Probably; especially when your dog is losing weight rapidly. Potential scenarios that can cause unexplained weight loss in dogs include:
- your dog is not getting sufficient nutrients
- the nutrients are lost
- the nutrients are not absorbed or utilized by the body
Other symptoms of concern include:
- loss of appetite
- ravenous appetite
- skin and coat changes
- altered drinking and urination
- changes in behavior
- changes in habits and routine
- panting, difficulty breathing or coughing
- reduced activity or exercise intolerance
- distended abdomen
Your dog is not getting sufficient nutrients
It does make sense to take a close look a the diet, especially if you recently changed your dog’s food. Don’t think that only inferior foods can cause problems—even an expensive brand can cause trouble.
For example, at one time, we experimented with various freeze-dried foods. One of them we tried contained turkey and chickpeas as main ingredients—sounds great, doesn’t it?
The chickpeas were ground into relatively fine grit visible after adding water. What I noticed, however, that my dog’s poop was full of identical particles. However, nutritional chickpeas might be, they went through my dog untouched by the digestive process.
No matter how wonderful the ingredients in your dogs food sound, they are useless of the body cannot use them.
If your dog isn’t eating, naturally, they’ll start losing weight. Food is essential to survival, though, and dogs instinctively know that. Generally, dogs won’t begin to refuse food unless they are seriously stressed, ill, or in pain.
It is imperative that you figure out the reason behind your dog’s anorexia. Some potential causes include:
- severe stress or anxiety
- serious illness
- severe dental disease
Further information: Loss of Appetite in Dogs: Why Did My Dog Stop Eating?
If your dog regurgitates, it means the food doesn’t even reach their stomach. While different from vomiting, regurgitation can lead to starvation.
Further information: Regurgitation in Dogs: Is It Different from Vomiting?
Anything that interferes with chewing or swallowing results in reduced interest in eating. Dental disease is one example but other conditions, such as masticatory myositis can have the same outcome.
Kidney or liver disease
Any condition that causes nausea will reduce the desire to eat, and it can lead to weight loss.
Your dog is losing nutrients
Vomiting or diarrhea
If your dog is throwing up, they are likely to be nauseous and not eating—which would technically fall into the earlier category. However, even if your dog is eating, diarrhea or vomiting leads to a severe loss of water and nutrients. Depending on the severity, though, dehydration can be the more imminent threat.
It is essential to identify and resolve the reason your dog is having diarrhea or throwing up.
One situation is particularly of note—when your dog’s poop is greasy, slimy, and clay-colored. You might be looking at insufficiency pancreatic deficiency, which is a condition when your dog is unable to digest their food. Your dog will eat ravenously but still starve.
Further information: Excessive Hunger in Dogs: What If Your Dog Acts Like They’re Starving?
Intestinal parasites can literally steal the nutrients your dog eats. While this problem is not as common as it used to be in the past, it can happen. Whipworms, in particular might be to blame.
Since whipworm infestation can also lead to loss of appetite, vomiting, and diarrhea, it is a double-whammy.
Some cancers have high metabolic demand and will rob the rest of the body of calories. Further, associated pain can make your dog lose interest in eating.
The kidneys process blood by filtering out wastes and toxins, while preserving nutrients and water and sending back into the body. When the kidneys don’t function properly, it leads to accumulation of toxins in the blood and/or loss of nutrients through urine.
Further information: Kidney Disease in Dogs – Say What? Canine Kidneys and the Associated Verbiage
Protein-losing enteropathy (PLE)
Sometimes, nutrients, such as protein, can be lost in the strangest ways. In PLE, protein is lost be excessively leaking back into the GI tract after already being digested and absorbed.
Despite initially mild symptoms, PLE can become a life-threatening situation fast. This problem goes far beyond the nutrient loss itself.
Along with weight loss, signs include ambiguous things such as:
- loss of appetite
- blood in the stool
Potential causes include GI disease, lymphatic disease, or heart disease.
Further information: Protein-Losing Enteropathy (PLE) in Dogs
Your dog’s body cannot absorb or utilize nutrients
Gastrointestinal disorders can lead to vomiting or diarrhea, resulting in nutrient loss. However, a diseased gut can also lead to malabsorption or maldigestion. What is the difference?
Maldigestion means that the GI tract cannot break nutrients down to their basic building blocks. Unless the food is taken apart into usable bits, it cannot get absorbed and passes through the digestive tract without the body being able to benefit.
Once the food is broken down/digested, the individual, broken-down nutrients pass through the intestinal walls for distribution through the body. If the intestinal wall is diseased, it is unable to perform this important part, which is referred o as malabsorption.
While the end result is pretty much the same, the causes are not.
After nutrients are digested, absorbed, and sent into the bloodstream, they still need to make their way to where they’re needed—the cells.
For example, a condition such as diabetes means that glucose accumulates in the blood while the cells starve for it.
Losing fat versus losing muscle
A generalized loss of muscle mass, not just fat, is usually a sign of more serious diseases such as kidney failure, liver failure, heart disease, or cancer. Orthopedic or neurological diseases can lead to loss of muscle mass too.
Abnormal Weight Loss in Dogs