Diet problems

My Dog is Too Skinny But Still Eats a Lot

Matthew Nesbitt
By Matthew Nesbitt, Journalist specialized in animal research. April 20, 2021
My Dog is Too Skinny But Still Eats a Lot

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A healthy dog will have a healthy appetite. It is not true to claim all dogs are greedy, but they need energy to exercise their natural behaviors such as running and playing. This energy comes from food, but how much they need to eat will depend on various factors. These will include their age, genetic makeup, size and state of health. We may think it common for a sick dog to lose their appetite, but not all dogs which eat well are well. This is especially so when we see the dog has lost a lot of weight, but has not lost their appetite.

At AnimalWised, we investigate why your dog is too skinny but still eats a lot. We understand each reason why a dog will lose weight and eat at the same time, as well as provide information on what to do in each case. As we will see, the best way to fatten up a skinny dog is often to treat the underlying cause of their weight loss.

You may also be interested in: My Cat Is Getting Skinny but Is Still Eating
  1. A poor diet
  2. Endocrine problems
  3. Parasitical infestation
  4. Dog breed
  5. Intestinal malabsorption syndrome
  6. Do I need to fatten up a malnourished dog?

A poor diet

Giving our dog the correct diet is an essential element to their basic care, but there are many factors to consider. The first is their age. Puppies will need a higher-calorific diet because they are still developing physically and cognitively. Senior dogs generally have less mobility, so they will need less calories. Larger dogs will also need more more calories than smaller dogs.

The quality of food you give your dog also needs to be correct. Although dogs can digest carbohydrates, they will need a feed which uses animal protein as its main ingredient. Some commercial feeds will use filler to either make the feed cheaper or do so under false claims of providing health benefits. In these cases, if the dog isn't getting the correct nutrition, they may lose weight while still eating what we perceive as a normal amount.

Homemade food can be a good way to control a dog's diet by ensuring quality ingredients and providing the right level of nutrition. However, every dog is an individual. We will need to go to a veterinarian to have the dog's dietary needs assessed before providing a homemade diet. If we do not tailor the food to the dog, they may become skinny even though they still eat a lot.

Endocrine problems

When we take our dog to the veterinarian to assess their dietary needs, we might find out they have health issues which affect their diet. Often, these problems can cause the dog to lose weight while increasing their appetite, a symptom which may seem counterintuitive. Endocrine diseases are those which affect the endocrine system, i.e. the system which sends messages in the body via hormones.

Often the endocrine disease causes imbalances in the dog's hormone levels. This means incorrect messages are sent to the brain, making them perform unnecessary or incorrect actions. This can include causing the dog to have an increased metabolism, meaning they burn off more calories than they can seem to eat.

There are various endocrine diseases in dogs which affect appetite and weight, including:

  • Hyperthyroidism: one of the most important elements of the endocrine system are the thyroid glands. Different problems can affect the thyroid, but one of the most common causes of canine hyperthyroidism is due to tumors. These can cause the gland to malfunction and result in weight loss despite eating normally. One of the most common and effective treatments is surgery to remove the tumor.

  • Diabetes mellitus: insulin is an essential hormone created in the pancreas which is very important for the endocrine system. If the dog has a pancreatic disorder, it often leads to diabetes mellitus. Diet is a very important factor in this disease and treatment is usually management of the disease via insulin injections.

  • Addison's disease: this is a disease which affects the adrenal glands and, therefore, the production of adrenaline. Causes of Addison's disease are varied, but are all related to damage to the adrenal tissue. These can include infections and tumors. Symptoms of this disease are quite non-specific, but they can include becoming skinny while still eating sufficiently. Treatment is usually dependent on the underlying cause, but most will need a dietary change.

Cushing's disease in dogs, a disease which affects levels of the hormone cortisol, is another endocrine disorder. While this can affect how the dog controls their weight, a common symptom is development of a pot-belly. This means they are not as likely to become skinny, although they may have an increased appetite.

My Dog is Too Skinny But Still Eats a Lot - Endocrine problems

Parasitical infestation

Another important factor to consider when a dog eats a lot, but becomes too skinny at the same time, is the possible presence of parasites. The symptoms of a parasitical infestation vary greatly, the most important variables being the type of parasite and the location of the infestation. When a dog becomes too skinny, but is still eating, this means they are usually affected by an intestinal parasite or one which affects the gastrointestinal system. These parasites include:

  • Roundworm: this is a parasitic nematode, usually of the Ascaris genus. They live in the stomach and intestines and can grow to be quite large. This affects the ability of the dog to metabolize properly, meaning they might eat a lot without getting the nutritional benefit. Puppies can be infested via their mother during breastfeeding.
  • Hookworms: so-called because they ‘hook’ onto the intestines of the dog. They absorb fluid and blood through their mouths and cause an imbalance in metabolism. They can be passed on form their mother or ingested from elements in their environment.
  • Tapeworms: another type of intestinal parasite which can affect a dog's metabolism. The tapeworms often cause increased appetite, but they may lose weight depending on the scale of the infestation.
  • Whipworms: act in a similar way to the previous parasites. They do not proliferate as much as they do, but they can live in a dog's body for extended periods of time. A common symptom of any intestinal parasite is that their poop can smell very bad and we can often see eggs in their feces.

Parasites are a common problem for dogs, but their symptoms can vary greatly. In fact, some infestations can be completely asymptomatic. However, we need to be sensitive to any changes in a dog's behavior and physiology, so take them to a veterinarian as soon as they are observed. Prevention of parasitical infestation is also important, so a suitable deworming schedule needs to be implemented.

When a puppy is losing weight, even if they appear to be eating, it is a serious cause for concern. This is because they are still developing and, therefore, more vulnerable to diseases such as parasitical infestation. This is why deworming schedules need to be established as soon as they are at a suitable age. Check out our article on how often a dog should be dewormed to know more.

Dog breed

A dog's genetic inheritance can affect their physiology. In terms of breed, there are some which are naturally skinny. They may still have a healthy appetite and it doesn't mean they are ill or have any other problems. It simply means they have a high metabolism and they will often expend a lot of energy. A common example of such dogs are the different types of sighthound, the most well-known being the Greyhound.

However, it is not only purebred dogs which can have high metabolism. There are many mixed-breed dogs which can have a genetic makeup which gives them a thin physiology. These can often be hyperactive dogs, as their energy output is high. We do not usually need to do anything other than ensure their diet is appropriate.

Intestinal malabsorption syndrome

Related to endocrine diseases, although not limited to this range of problems, intestinal malabsorption syndrome refers to various problems which cause the intestines to function improperly. Essentially, it is a failure in digestion and it can cause serious harm to the dog. However, some low-grade malabsorption problems can be asymptomatic or only result in symptoms later in life.

Symptoms of malabsorption syndrome most often include chronic diarrhea, but many other symptoms can present. These include weight loss, despite still eating normally. Causes of malabsorption syndrome include:

  • Exocrine pancreatic insufficiency
  • Bacterial overgrowth in the intestine
  • Infectious agents including viruses, bacteria and fungi
  • Dietary allergies
  • Inflammatory bowel disease

In these cases, we need to take the dog to a veterinarian to determine the underlying cause. Suitable treatment will be implemented, something which often required dietary changes.

My Dog is Too Skinny But Still Eats a Lot - Intestinal malabsorption syndrome

Do I need to fatten up a malnourished dog?

It is very important we understand that a dog losing weight, but still eating, is usually a symptom of an underlying disease or medical condition. This is different from a dog which has lost weight because they have been starved of food or because they are malnourished due to an incorrect diet. In the latter situations, we can change the diet to help a dog be brought up to their ideal weight.

To know how to fatten up a malnourished dog, and find out reasons why they are not eating correctly, take a look at our article on how to put weight on a dog.

For the other reasons why a dog is too skinny, we need to treat the underlying cause. For cases where the dog has an infection or infestation, ridding the dog of these problems should restore their digestive health. After this time they should put weight back on naturally.

When a dog has an untreatable disease, such as certain endocrine problems or malabsorption issues, the symptoms will need to be managed. For example, diabetes in dogs will require insulin treatment after assessing their insulin levels. A change in diet is likely needed, but this will depend on the specific cause. Only a qualified veterinarian will be able to determine the specific dietary changes required for each dog.

If you want to read similar articles to My Dog is Too Skinny But Still Eats a Lot, we recommend you visit our Diet problems category.

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My Maltese has a bloated stomach and he is losing weight and is skin and bones. He is eats and takes walks. Should he have antibiotics?
What worm medicine can I give my large Dog for all the different worms !!
Administrador AnimalWised
Hi Prissy,

If your dog has worms, you will need to go to the vet so they can determine which type they have. Only then can the right antiparasitic agent be used.
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My Dog is Too Skinny But Still Eats a Lot