I’m sure you've heard the word “metabolism” thrown around – especially when the subject of weight comes up. Some lucky people find it easy to stay thin, and we say that they are blessed with a “good metabolism.” On the other end of the spectrum are those who are not so lucky and who struggle daily just to lose a pound or two—perhaps their “slow metabolism” is to blame. I have two cats—one is lucky in this way, the other? Not even close.

We may use the term metabolism this way, but medically, metabolism is at the core of the basic functions of the body—without it, we would simply not be. Medically speaking, metabolism is the process the body uses to make energy from the food we (and our pets) eat. The protein, fats, and carbohydrates your pets consume are turned into fuel for every living cell in their body. This fuel can be used right away, or it can be stored as energy in the tissues of the body and used when needed.

Metabolic diseases are anything that disrupts the process of metabolism. This could be a disease in a specific organ, or it could be a systemic disease that affects the overall health of a pet. Metabolic diseases differ from infectious diseases in that there is no inciting organism that causes it. Some pets are prone to metabolic disease based on heredity, breed, or age, and some simply acquire metabolic disease for no known reason.

Common issues in cats


The hormones produced by the thyroid regulate many other body systems and play a key role in how quickly our pets’ bodies use energy. Cats with hyperthyroidism have an overactive thyroid, making for a lightning fast metabolism. Affected cats generally lose weight despite a voracious appetite. Before you call these cats lucky, remember that hyperthyroidism also has a negative impact on other body systems, such as the heart.


Obese cats are prone to non-insulin dependent diabetes (otherwise known as Type 2 diabetes). Normal amounts of insulin are produced by the pancreas, but it’s just not as effective as it needs to be in these patients and blood glucose levels do not remain in check.

Chronic renal insufficiency

Kidney disease is a common ailment of geriatric pets. Of course, the kidney’s most famous role in the body is to eliminate waste products by excreting them into the urine. When kidney function declines, so does the ability to efficiently clear waste products.

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Common issues in dogs


Dogs with hypothyroidism have exactly the opposite problem that cats with hyperthyroidism do. Where cats have an increased metabolism, dogs with hypothyroidism find themselves lacking enough thyroid hormone, causing a sluggish metabolism. They become lazy and overweight with a poor coat quality and dry skin. Luckily, hypothyroidism can be treated with thyroid hormone supplementation.

Hyperadrenocorticism (Cushings syndrome)

Hypoadrenocorticism (Addison’s disease)

Both of these diseases involve abnormal production of cortisol, which regulates the metabolism of proteins, fats, and carbohydrates.


For the most part, dogs get insulin dependent diabetes, unlike their feline counterparts who can sometimes be maintained without insulin injections.

Metabolic diseases are common in our pets. Diagnosing them may be as simple as running some basic blood work, or it may be more extensive than that. Pay attention to little signs, especially as pets age. An increase in the amount of water they drink or a change in appetite could signal trouble brewing. Bring these issues up with your pet’s vet to get to the bottom of things.

Mar 13, 2014
Pet Health

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