Feline Diabetes

Lisa A. Pierson, DVM

Warning:  Before reading even the first sentence of this webpage, you must commit to reading past the STOP sign below.

Diabetes is one of the most common feline endocrine diseases and, while we do  not know all of the causes of this complex disease, we do know that many diabetic cats cease needing insulin or have their insulin needs significantly decrease once their dietary carbohydrate level is decreased to a more species-appropriate level than that found in many commercial foods. 

Although all dry foods are too high in carbohydrates, please be aware that many canned foods also contain far too many carbohydrates making them very poor choices for cats.

Cats are obligate carnivores and are not designed by nature to consume a high carbohydrate diet.  If you have not read my article on this site entitled Feeding Your Cat: Know the Basics of Feline Nutrition, I urge you to do so.  This article, and the Feline Urinary Tract Health article, explains why it is very illogical to feed any cat a high carbohydrate, water-depleted diet of dry kibble.

Feeding a diabetic cat a high carbohydrate diet is analogous to pouring gasoline on a fire and wondering why you can't put the fire out.

This rationale also applies to any of the prescription dry diabetes diets such as Purina DM, Hill's Prescription w/d and m/d, and Royal Canin DS.  These diets are not only poor quality diets, they are still too high in carbohydrates and contain several species-inappropriate, hyperallergenic ingredients such as corn, wheat, and soy.

It is very important to address the carbohydrate level in a cat's diet but it is 'tunnel vision' nutrition to stop there.  We need to also address the quality of the ingredients in the foods that we feed to our cats - not just the carb level.

I do not use any of the prescription diets - even in the canned form - since there are better - and often less-expensive - choices in the over-the-counter (non-prescription) market.

Please understand that there is nothing 'magical' about the prescription diabetes-management diets other than the fact that the dry versions of these products are lower in carbohydrates than the majority of dry cat food products on the market. 

In addition to the dietary carbohydrate level, we also need to address the issue of 'portion control' (managing caloric intake) of any food that we choose to feed to our cats because obesity is a very important factor to consider when discussing both the causes and treatments of diabetes.  Adipocytes (fat cells) secrete a substance that makes the cells of the body resistant to insulin.

Portion control has recently become even more important because as pet food manufacturers move toward making more grain-free (low-carb) foods, this process is selecting for high fat diets.  Keep in mind that we get our calories from 3 nutrients:  proteins, fats, and carbohydrates.  The percentage of calories that come from these 3 nutrients must add up to 100%.  Therefore, if we lower the percentage of carbohydrates in the food, that means we must either increase the protein percentage or the fat percentage - or both.  Given the fact that fat is cheap and protein is expensive, you can see that profit margin drives pet food manufacturers to make high fat foods when they making grain-free products.

Fat contains 9 calories per gram whereas proteins and carbohydrates are only 4 calories per gram. Therefore, fatty foods are very calorically dense making portion control important to consider.

Lack of exercise (activity level) has also recently become an issue that is gaining more attention as it relates to both the cause and management of feline diabetes.

Even though we need to be careful to not necessarily assume that what is 'right' for a human is also 'right' for a cat, the need to consider carbohydrates, obesity, and activity level should come as no surprise since these factors are are also significant issues in human diabetes.

See this chart for the carbohydrate content of many canned foods.  Take a look at Merrick Cowboy Cookout as a nice example of a good protein/fat/carbohydrate profile.  In general, aim for below 10% of calories from carbohydrates.  Keep in mind that this chart only addresses the food's composition in terms of calories from protein/fat/carbohydrates and does not address the quality of the ingredients.

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                 Very Critical Points

If you do not read any further on this webpage, please understand the following principles.  Your cat's life literally depends on your understanding of these issues.

Many cats that are in a diabetic state no longer need any insulin when they are finally fed an appropriate low-carbohydrate diet.

Others will always need some insulin but the amount necessary to maintain proper blood glucose levels is nearly always significantly reduced once the patient is on a low carbohydrate diet.

Please re-read the previous two paragraphs carefully. 

If you change your diabetic cat's diet to one with lower carbohydrates, he will, in all probability, IMMEDIATELY (not days or weeks later) require a reduction in his insulin dosage.  He may also immediately go into 'remission' and not need any insulin at all. 

If this warning is ignored, you may very well end up with a cat in a hypoglycemic crisis (dangerously low blood sugar) which can result in death, or brain damage.

If you take only one point away from this page, it needs to be the understanding that if you stop pouring carbs into your cat by switching to a low-carb canned food diet (or even a dry food diet with lower carbs than you have been feeding), you MUST be aware of the probable immediate and significant impact on your cat's insulin needs.

If I could shout this from the rooftops, I would. 

On a weekly basis, I hear of reports of cats that ended up near-death - or actually did die - from insulin overdoses because lay caregivers and veterinarians did not understand this basic concept.

I often hear of my colleagues recommending "re-testing in a month" - while the caregivers are implementing a diet change along with administering a set amount of insulin - which is often too high.

Or - the caregiver reads this article and decides to change the diet on their own and does not understand the need to lower the insulin dosage.

When someone understands half of the concept (changing to a low-carb diet), but does not understand the other half of the concept (the highly probable need to lower the insulin dosage) disaster often strikes.

Remember the statement that I made above?  The one about pouring gasoline onto a fire?  If you stop pouring gas on a fire, there is going to be an immediate reaction of that fire when its fuel is taken away.  That fire is not going to take weeks or a month to respond.

In this analogy it would not be a big issue if you kept 'drowning' that dying fire with water but in this instance water = insulin and a hypoglycemic crisis can ensue if more insulin is given than is needed by the body.

Of course, carbohydrates are not the only fuel for a diabetic 'fire' but they play a very significant part in contributing to high blood sugar levels in a diabetic cat.  If you minimize this issue - and do not lower the insulin accordingly -  you really will be 'playing with fire' with regard to the safety of your cat.

So you say - "OK!!  I get it!  I understand that my cat may very well need a lower dose of insulin - or may not need insulin at all - once I stop pouring gasoline (carbs) onto his diabetic fire, but how do I know what dosage of insulin to give?  How do I know what impact the new diet is going to have on his insulin needs?  How do I keep my cat safe?"

This is where in-home blood glucose monitoring comes into play.

Trying to manage a diabetic cat without home testing is a bit like driving a car with a paper bag over your head.

The best way to arrive at the optimal dosage of insulin and the optimal dosing frequency is by home testing.  Note that I said "optimal".  Many diabetic cats have survived with a set amount of insulin being administered twice daily with the dosage determined by periodic glucose curves performed at a veterinary clinic if their owners will not, or cannot, home test.  However, this is not the safest and most physiologically sound way to manage a diabetic patient so I urge all diabetic cat caregivers to strongly consider home testing.

Every case is different and definitive recommendations with respect to how far to lower the insulin dosage (when you start the diet change) cannot be given without knowing the specifics of each case.  There are many crucial factors to be considered:

• carbohydrate content of the original

• carbohydrate content of the new diet

• how fast the change to a low carb diet is made

• how carb 'sensitive' the cat's body is

• how quickly the cat's body responds to the decrease in carbs

• how the cat, in general, reacts to insulin

• has the cat ever been positive for ketones in his urine

• current dosage of insulin

• current blood glucose levels of the patient

• etc.

I urge you to keep the lines of communication open between you and your veterinarian while learning to home test and implementing the diet change.  That said, it is unfortunate that many veterinarians are not well-versed in the management of feline diabetes and all too often do not fully understand the strong connection between diet and blood sugar levels. 

It is also very frustrating to note that many veterinarians either are not aware that home testing is possible (despite the subject being discussed in many veterinary journals and at many continuing education meetings) or just simply do not support this life-saving tool.

Additional help and support can be found on the Feline Diabetes Message Board and I urge all diabetic cat caregivers to join this forum as a support system to be used in conjunction with your veterinarian. 

Keep in mind that with all internet forums, the experience and knowledge base of the participants will vary. 

If posting to forums is not within your comfort zone and you would like additional help, I am available for phone consultations.  Please understand that I cannot offer individual case advice via email.  Feline diabetes can be a very complicated disease to optimally manage and it would not be ethical or time-efficient to attempt to address individual case management of this disease via email. 

If you have read Feeding Your Cat: Know the Basics of Feline Nutrition along with the first part of this webpage and are convinced that you need to start feeding your cat(s) correctly (low-carb, canned or homemade food) and want to skip the rest of this article, please head right to the changing the diet safely and the home testing sections below.

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If you want to know more about the physiology of diabetes and why a low carbohydrate diet is so important for this species, please click on the first four links below.

The basics of diabetes

The cat's unique metabolism

Carbohydrates, obesity and diabetes

Optimal nutrition for all cats

Switching the Diabetic Cat to a Low Carbohydrate Diet - SAFELY!

In-home blood glucose monitoring

The Basics of Diabetes

All cells in the body use glucose ("blood sugar") as their source of energy.  However, in order for glucose to provide nourishment to the cell, the glucose must get inside the cell.  Insulin, which is produced by the pancreas, is the substance that tells the 'front door' of the cell to open up in order to let the glucose inside.  If this system is disrupted for any reason, the glucose cannot enter the cell and subsequently, the level of glucose increases in the blood stream (hyperglycemia) and the cells go 'hungry'.

There are two types of diabetes.  Type 1 and Type 2.  Type 2 is the more common form in both humans and cats.

Type 1 occurs when the beta cells of the pancreas are not able to produce enough insulin.

Type 2 is characterized by two problems.  The first, as in Type 1, is a diminished ability of the pancreas to secrete insulin.  The second issue is one of insulin resistance.  In other words, the receptors on the cell wall that would normally open the door to the cell to let the glucose in when insulin 'knocks', stop 'listening' to the insulin. The cells 'resist' the signal that the circulating insulin is sending and the glucose is not transferred to the inside of the cell, resulting in an elevated blood glucose (hyperglycemia) and cellular 'starvation'.  The elevated blood glucose, in turn, sends a signal to the pancreas telling it to secrete more insulin.  The elevated insulin may somewhat override the insulin resistance resulting in more glucose entering the cells, but eventually the pancreas can become exhausted or 'burned out'.

Glucose toxicity results from chronic hyperglycemia.  Glucose toxicity wreaks havoc on the entire body - especially the pancreas and its insulin-producing cells.  A vicious cycle then ensues as the insulin-producing cells are damaged resulting in less insulin being produced.

Here is a picture of the pancreas.  It is the long, flat, pink organ in the center.  The dark red organ below it is the spleen.  The white tissue is all fat. This is also called "omental fat" and some of you may have heard or read about this type of fat in humans.  It is the fat that is carried around the abdomen and is associated with significant health problems.

The Cat's Unique Metabolism

In my article, Feeding Your Cat: Know the Basics of Feline Nutrition, I explain what it means to be an obligate carnivore.  For a more technically detailed presentation of this subject matter, please see Dr. Debra Zoran's wonderful article entitled The Carnivore Connection to Nutrition in Cats.  

Cats are obligate carnivores and, as such, are uniquely adapted to consume a diet that is high in protein, contains a moderate amount of fat, and that includes a very small amount (3-5 percent) of carbohydrates.  Since nature designed them to ingest very few carbohydrates, cats lack many of the important enzymes that are necessary to process this type of food efficiently.

With the above information in mind, consider the fact that the carbohydrate level of most dry foods is between 35-50 percent with some of the lower quality dry foods being even higher.

Robbie has been designed by nature to eat meat, not grains.

The three main 'take-home' words from my Feeding Your Cat article are "proteins" (animal versus plant), "water", and "carbohydrates".   For this article, the most important of the three subjects is carbohydrates.

Carbohydrates, Obesity and Diabetes

Most people are aware that diabetes is more common in overweight humans than it is in people closer to an optimal weight.  The same is true for cats.  Fat (adipose) cells produce a substance that causes the cells of the body to become resistant to insulin.  This increase in insulin resistance is the hallmark of Type 2 diabetes.  As mentioned above, this is the most common form in the cat.

Cats are designed to utilize proteins and fats for their energy - not carbohydrates.  They are lacking the necessary enzymes to efficiently utilize carbohydrates to meet their energy needs.  When the carbohydrate level of an obligate carnivore's diet is higher than it should be - remember that a bird or a mouse is only 3-5 percent carbs and that most dry foods contain between 35-50 percent carbs - the excess carbohydrates are stored as fat.  The increased fat cells, in turn, promote Type 2 diabetes via an increase in insulin resistance.

That said, if calories in exceed calories out - no matter whether the calories come from protein, fat, or carbohydrates - the cat will gain weight.  This is why portion control is important no matter what diet you are feeding.

Mindy (left) is nice and lean and full of energy.  Molly (right) was rescued from  a home where only dry food was free-fed and she had become terribly obese.  She could barely walk and could not even clean herself.  She has gone from 20.5 pounds to 13 pounds simply by eating a low-carbohydrate canned food (Wellness) and having all dry food removed from her diet.  She now runs, jumps and plays like a normal cat!  For more on her story click here and here.

Not all carbohydrates are created equal, but it is safe to say that obligate carnivores - especially diabetic ones - do not benefit from carbs at a level above what would be in their natural diet regardless of the type.  But that said, carbohydrates are characterized by their Glycemic Index (GI) and their Glycemic Load (GL) which are measurements that reflect how high and how rapidly a specific carb causes a rise in blood glucose when ingested and the overall impact that particular carb has on the diabetic state.  The higher the GI/GL of a carbohydrate, the worse the result will be for a diabetic patient although GI/GL of various ingredients has not been studied in cats like it has been in humans.

The Glycemic Index and Glycemic Load values of different food sources are very important to consider for people trying to manage their own diabetes.  However, I do not like to concentrate on these values for cats because then it sounds like there may be "good" carbs versus "bad" carbs for cats.  The bottom line is that humans are designed to utilize carbs whereas cats are not.  What we can say is that some carbs, such as the grain flours, are worse (higher GI/GL) than other carbs, but ideally, we should strive to keep the carb level of the feline diet at a level which would be found in nature. 

Please see a discussion of food choices at Commercial Canned Foods.  This list was originally compiled in order to benefit the food intolerant/IBD (Inflammatory Bowel Disease) cats that I work with.  The culprit in this disease process is often specific hyperallergenic/high carbohydrate grains such as corn, wheat, and soy.  In addition to these grains, yeast can also be hyperallergenic. So for this reason, you will note that the list is split into two sections - With Grains and Without Grains.   The "With Grains" list only includes products that do not contain corn, wheat, or soy.

For the diabetic cat, however, the caregiver should ideally focus on keeping all grains out of the diet.  While an IBD cat may be able to tolerate rice, this is definitely not an ingredient that you want to feed to a diabetic cat - or any cat, for that matter. 

Buck still needs to lose a bit more weight on his low-carb diet.

Unfortunately, pet food labels are extremely lacking in useable information.  All that is required to be listed is the 'guaranteed analysis' which are only minimums and maximums which are, by definition, inaccurate.  Also, it is not required to list the carbohydrate content.

It is sometimes stated that you can subtract all of the percentages on the label from 100 percent in order to give you an approximate percentage of the carbohydrates contained in any product. In other words, subtracting the protein, fat, water, fiber, and ash/mineral content from 100 percent will leave you with the percentage of carbohydrates contained in the diet in the diet on a 'wet matter' or 'as fed' basis.  However, because the guaranteed analysis values are only listed as minimums and maximums with no 'floor' or 'ceiling', you can see where this type of calculation can lead to a very erroneous conclusion with respect to the carbohydrate content.  Also, you need to convert this number to dry matter basis.

More on this subject can be found on my Commercial Canned Foods page.

A valuable site that lists the carbohydrate content of many commercial foods is Janet and Binky's site.  This site lists values that are percentages of calories, not percentages of weight. This can get very confusing and lead people to wonder why two different lists show different numbers for the same product.  For instance, most pet food manufacturers list the ingredient numbers for their products as percentages of weight, not of calories.  Both methods are acceptable but 'percentage of calories' is the preferred method to use. 

Unfortunately, many of the foods on the market (including those listed on the Commercial Canned Foods page) are not included on Binky's list.  For these foods, I suggest that you contact the companies and ask them for their carbohydrate values - preferably in terms of 'percentage of calories' which is also known as 'metabolizable energy' (ME).

Optimal Nutrition for All Cats

I long for the day when veterinarians start thinking outside of the Big Four 'box' and stop being so 'married' to Hill's, Purina, Iams, and Royal Canin since there are higher quality - and less expensive - diets available over-the-counter (non-prescription).

We have all heard the phrase 'locking the barn door after the horse is gone'.  This applies to how we feed our cats with respect to the diseases that they commonly develop secondarily to being fed a low quality, species-inappropriate diet.  For instance, when looking at feline diabetes, notice that the rationale behind the diabetic prescription diets is to provide a decreased carbohydrate level in the food to 'treat' a diabetic cat. 

However, why not recommend a decreased level of carbohydrates for all obligate carnivores to possibly prevent diabetes in some of these patients?  Why are we always addressing treatment rather than prevention?  Why aren't more veterinarians making common sense-based recommendations for their healthy patients in order to prevent diseases such as diabetes, IBD, urinary tract disorders, etc., that are, in some cases, strongly linked to a high carbohydrate /high grain /water-depleted diet?

While the typical diet of an obligate carnivore contains less than 5 percent carbohydrates, you should strive to at least keep their diet below 8-10 percent carbohydrates.

The subject of fiber is also widely discussed with respect to feline nutrition and diabetes.  It was once thought that a high fiber diet would be beneficial for blood glucose control in the diabetic cat but this recommendation has since fallen out of favor.  Please see Dr. Zoran's article for more details.  A cat's natural diet is very low in fiber.  Cows and horses are designed to eat a high fiber diet - not cats.

Let's take a look at some of the ingredients and the carbohydrate content in several prescription diets often recommended for diabetic cats.  I have underlined the sub-optimal and species-inappropriate ingredients.  For a more in-depth look at reasons why these ingredients do not constitute optimal nutrition, please see my Feeding Your Cat article. 

In summarizing the points in that article, please take note of the fact that the Hill's Prescription products listed contain no muscle meat.  By-products or organ meats are used instead.  (Please see my discussion regarding by-products which can be highly nutritious sources of protein but can also include low quality ingredients and diseased organs.) 

In addition, note the high carbohydrate levels in all of the listed products except for the Purina canned DM.  Also notice the common usage of high glycemic index grain flours, the use of hyperallergenic ingredients (corn, wheat, soy, and yeast), and the use of known carcinogenic preservatives.

Powdered cellulose is fiber source obtained from plants/trees.

Hill's Prescription dry m/d:   (16% carbohydrates)

Chicken by-product meal, corn gluten meal, pork fat, pork protein isolate, powdered cellulose, brewers rice, ground whole grain corn,wheat gluten, dried egg product, chicken liver flavor*

Hill's Prescription canned m/d:  (16% carbohydrates)

Pork by-products, pork liver, water, corn starch, powdered cellulose, soy protein isolate, chicken fat,......rice flour

Hill's Prescription dry w/d:  (37% carbohydrates)

Chicken by-product meal, corn gluten meal, brewers rice, rice flour, powdered cellulose, chicken liver flavor*, soybean oil.....preserved with BHT, BHA and ethoxyquin

Hill's Prescription canned w/d:  (28% carbohydrates)

Pork by-products, pork liver, water, corn flour, powdered cellulose, chicken fat, chicken liver flavor*

Hill's Prescription canned w/d with* chicken: (26% carbohydrates)

Water, pork liver, pork by-products, chicken, powdered cellulose, corn starch, oat fiber, guar gum......locust bean gum, carrageenan, chicken liver flavor*

*Please be aware that the word "with" means that a product is required to contain only 3% of the ingredient - in this case, chicken.  Also, the word "flavor" means that the product is not required to have any of the ingredient present.

Now let's look at two Purina products:

Purina dry DM:  (15% carbohydrates)

Poultry by-product meal, soy protein isolate, corn gluten meal, soy flour, beef tallow preserved with mixed-tocopherols (source of Vitamin E), corn starch,.....brewers dried yeast

Purina canned DM:  (8% carbohydrates)

Water, Liver, beef, corn gluten meal, trout, animal fat, fish meal, powdered cellulose, soy protein isoloate

When comparing the Hill's products with the two Purina DM choices, if I had to choose between them, I would pick the Purina canned DM.  But fortunately, we do have other choices.  One of the biggest mistakes I see veterinarians make is choosing a diet based on addressing a single disease entity.   This is very narrow-sighted.  The Purina canned DM favorably addresses the overall carbohydrate level but it also contains corn, wheat and soy and it contains predominantly liver versus a muscle meat.  These ingredients are certainly not what a cat would choose to eat in the wild. 

I choose to feed a cat for overall health, not just to address one disease state such as diabetes - especially when there are products available that are even lower in carbohydrates and contain far superior ingredients for carnivores than the products listed above - and are less expensive.  When I look at the Hill's and Purina ingredients, these are not products that I would choose to feed to my patients or my own cats.

Regarding dry food addicts - please see Tips for Transitioning Dry Food Addicts to Canned Food.

Many cats are fixated on dry food and refuse to eat canned food.  For these cats, I would switch them to EVO or Nature's Variety Instinct dry food while the human works very hard at getting them to eat a properly hydrated diet of low carbohydrate canned food.  These two dry foods are lower in carbs than most dry foods but are still too high for long-term use.

Plus, they are water-depleted, which will wreak havoc on the urinary tract system, and they are very calorie-dense (high in fat) and palatable. These last two issues will often promote weight gain in cats which is counterproductive in overweight diabetic cats.

I am a firm believer that all cats will eventually eat canned food if the human implements a healthy dose of patience and perseverance as discussed in my Tips for Transitioning paper linked above.  It is definitely more difficult with a diabetic cat due to the fact that they must eat when receiving insulin, but it can be done!  I see people 'throw in the towel' and give up far too soon on these stubborn, dry food-addicted cats. 

Let's now take a look at look at canned Wellness:

Wellness canned Chicken:  (Most varieties range from  2-5% carbohydrates)

Deboned Chicken, Chicken Liver, Turkey, Chicken Broth, Sweet Potatoes, Carrots, Vegetable Gums, Flaxseed, Potassium Chloride, Alfalfa, Cranberries, Blueberries, Yellow Squash, Yellow Zucchini

Note the absence of any grains and the very low carb content.  Also note the high level of muscle meat - versus by-products and organ meat - and the lack of any dangerous preservatives.  These products are also void of the commonly used hyperallergenic and high glycemic index ingredients such as corn, wheat, soy and yeast.

Sweet potatoes, carrots, alfalfa, etc., do not belong in cat food but you can tell by the low carb content that these ingredients are not present in very large amounts.  They are there to appeal to the human reading the label - not because cats need these ingredients in their food.

Surprisingly, contrary to what the name implies, sweet potatoes have a lower GI/GL than the common white potato - at least in humans. Still, it would be preferable for this ingredient to be absent from a cat's diet.  Unfortunately, all commercial diets have some cons associated with them which is why I choose to make my own cat food.  You have to pick your battles when it comes to the world of commercial cat food options so don't drive yourself nuts when reading ingredient labels.

Switching the Diabetic Cat to a Low Carbohydrate Diet

Caution:  This must be done very carefully if the patient is already on insulin.  See above if you have not already read the Critical Points section.

If your cat is not on insulin because he was just diagnosed with diabetes, then you can change the diet more rapidly - either immediately ('cold turkey') or within 2-3 days.  More on this issue below.

Unless the patient's clinical signs warrant immediate insulin administrationl, I try a diet change - with no insulin - for 5-7 days to see what impact the new diet will have on the blood glucose. In most cases, I do not agree with waiting much longer than a week to start insulin. This is because you will have the best chance of getting your cat into remission (cease needing insulin) if both diet and insulin are used very early on.  The longer your cat's body is under the effects of glucose toxicity, the more his body will be damaged and the less chance of remission he will have.

When I have a new diabetic patient present to me, the two most important tasks are:

1) getting the patient onto a low carbohydrate diet - preferably canned and not dry

2) teaching the client how to home test   

If your cat is already on insulin, the safest way to implement a diet change is to incorporate home testing into your management protocol.  

You also need to discuss any diet change with your veterinarian but be aware that many vets underestimate the degree to which the insulin dosage needs to be lowered when a low-carb diet is implemented - which can put the patient in danger.

For example, let's consider a cat that is currently eating Hill's Prescription dry w/d with 37 percent of its calories coming from carbs and he is suddenly switched to canned Wellness at 3-5 percent carbs.  If the insulin is not lowered accordingly, an overdose of insulin will occur.  Please do not underestimate the favorable impact that a low-carb diet has on decreasing the blood glucose level of a cat. As stated at the beginning of this page, many cats no longer need any insulin once on a low carb diet.  Others have a drastic decrease in the amount of insulin needed to maintain an optimal blood glucose level.

The goal is to get your cat off of dry food and on to a 100 percent canned food diet but if your cat is on insulin, this must be done carefully - especially if the cat refuses to eat canned food.

Giving a full dose of insulin to a cat that is not eating can result in life-threatening hypoglycemia.

Many of the tips that I offer in the Transitioning Dry Food Addicts to Canned Food section of my Feeding Your Cat article can be used for diabetic cats but please be cautious as you implement them if you are also injecting insulin.

A non-diabetic cat can very safely handle the 'tough love' 12-18 hours period of time without food that is often necessary to get them to change their diet but this does not apply to a diabetic patient, therefore switching a stubborn diabetic cat can be more difficult.  It is not impossible but the process does have some complicating factors.

With a stubborn cat that is a dry food addict, approach the diet transition slowly and with a high dose of patience.  For cats that like canned food but are still eating a 100% dry food diet, the transition can proceed much more rapidly as long as the blood glucose is being monitored and the insulin is being adequately adjusted downward.  I cannot stress this last point strongly enough.

When defining "rapidly", I have, as noted above, switched many cats from dry to canned 'cold turkey' without any digestive problems (vomiting or diarrhea) - especially those cats that are already eating some canned food in addition to their dry food.  However, you can also error on the side of caution and go slower than I would - taking ~1 week to make the switch.

With regard to the issue of diarrhea and a diet change - I don't mind a bit of loose stools (tooth paste +/- with a bit of pancake batter-consistency) and tend to keep on with the canned food diet.  These loose stools often firm up within a few weeks on the new diet.

Some cats will vomit when changed to canned food. The transition must be slowed down for these patients because it is very important for them to have food 'on board' in order for the insulin to have something to work with.

There are many cases of success stories on the Feline Diabetes Message Board that discuss cats ceasing to need insulin once all dry food was removed from the diet.

In-Home Blood Glucose Monitoring

Few humans with diabetes would dream of trying to mange their disease without the use of a glucometer ("meter") to test their blood glucose level prior to injecting insulin.  Injecting insulin blindly - into a human or a cat - is not without risk.

This includes feline patients that have their doses determined with glucose curves done at a veterinary hospital.  This is because your cat's insulin needs can change for a variety of reasons (infection, stress, anorexia, etc.) and also because the curve generated at the vet clinic is often influenced by stress hyperglycemia which is a 'false' increase in blood glucose due to the cat's internal reaction to this stress. This can then result in a higher dosage of insulin being prescribed than will be needed by the patient when they are at home.

Believe me, I understand that the issue of home testing can be quite intimidating at first.  Most people become very stressed when first learning of their cat's diabetes diagnosis and can't even imagine injecting their cat with insulin, let alone getting a blood sample from their ear!

Awhile back I decided to pretend that I was a new diabetic cat owner.  I went to test 7 cats in my home (my own and foster cats).  Needless to say, it was frustrating - and not as easy as I was expecting it to be - but I finally got them all tested.

Several cats took 5-7 pokes (in different sessions) to get enough blood for a reading.

Only 1 out of the 7 'guinea pigs' gave up enough blood the first time to get a reading.

I, on the other hand, was bleeding like a stuck pig. The lancet was going through the cat's ear and right into my finger. I was bleeding. The cat was not.  I started 'practicing what I preach' and got a cotton ball to protect my finger while I kept working to find the 'sweet spot' in the cats' ears so that I could get a blood sample from them.

The moral of the story?  Be patient. Be kind to yourself.  Give it time and it will come.  Maybe not the first day and maybe not even the first week but most people (and cats) get the hang of home testing.

Oh...and cat ears tend to bleed a bit easier after they are poked a few times.  Do not worry about this!  It is a good thing and your cat's ears will be fine!

A very valuable resource and a great group of supportive people can be found at the Feline Diabetes Message Board. On a daily basis, board members talk 'newbies' through the trials of learning how to home test. It is always fun to see these scared, apprehensive new people then go on to help others once they have mastered home testing.

If you or your veterinarian need some convincing that home blood glucose monitoring is critical to the optimal management of feline diabetes, here is a list put together by a member of the Feline Diabetes Message Board of many veterinary and PubMed articles discussing the value and validity of blood glucose monitoring of cats.

Two veterinary journal articles can  be found here and here that verify the accuracy of these meters for use in diabetic pets.

Sadly, many of my colleagues either do not introduce their clients to this life-saving tool or, worse yet, dissuade their clients from the practice of home monitoring.  This lack of pro-active management has resulted in the death of many cats and the less-than-optimal management of countless others.

That said, there are rare cats that will not allow home testing.  I say "rare" because if the cat allows insulin injections, they will almost always allow you to test them - eventually - so don't give up too quickly.

Meters, test strips, lancets, lancet pens:

The meters that are used by humans can also be used to successfully monitor a diabetic cat.

You do not need a meter designed especially for pets such as the AlphaTrak which costs ~$100 and uses very expensive test strips ($1 per strip). The cost of the meter is not as much of a factor as the ongoing cost for the test strips.

There are many meter models to choose from.  You can often get the meters for free (or around $10) when you purchase 50 - 100 strips since the manufacturers want to get you locked into buying their strips.  (Think about cheap printer prices - they are cheap because the companies want to get you locked into buying their expensive ink cartridges.)

Hocks is a good place to buy meters and strips online. 

Ebay is also a good place to buy strips but watch the expiration dates.

There are two important factors to consider when buying a meter:

1) cost of strips (range $0.35 - $1 each)

2) amount of blood needed  (range = 0.3 - 1.0 microliters)

The One Touch Ultra is a very good meter in terms of accuracy - and is used by many people on the FDMB - but it requires 1 uL of blood which can be hard to get from some cats' ears so you may want to consider sticking with a meter that requires only 0.6 uL or less. The OTU strips are also very expensive when compared to the cost for strips used by other meters.

Many people really like the Walmart ReliOn.  The meter and its strips are cheap and the meter has been shown to be reasonably accurate. (People often bring their glucose meter with them to their vet appointments to compare with the results their vet gets.)  The Walmart ReliOn uses .6 uL of blood.

11/22/09 update from a FDMB member:  "The newer Walmart meter is the ReliOn Micro - it only uses .3 uL of blood and is much, much nicer that the older meter. It sips quickly and allows a long time from inserting the strip to get the sample."

Other favorites include the Ascencia Contour (.6 uL), Accucheck Aviva (.6 uL), and the Freestyle (.3 uL).

The TrueTrack has not been getting very good reviews on the Feline Diabetes Message Board lately so you may want to to stay away from that meter.

It is important to get a meter that uses 'wicking' test strips which all of the above meters use.  These strips automatically draw the blood into the testing area as soon as the edge of the strip contacts the edge of the blood drop. This is in contrast to the type of meters that use strips requiring that the blood be dropped directly onto the test strip.

Lancets (the 'pokers') range in size from a large 25 gauge to a very small 33 gauge.  However, most companies do not state the gauge size on their lancet boxes so it can be confusing when trying to figure out which lancets to buy.  Generally speaking, when you see lancets labeled "ultra-fine" or "ultra thin", that denotes a very fine lancet size (31,32,33 gauge).  Exception to the word "ultra" is the LifeScan One Touch UltraSoft lancets.  They are 28 gauge and many people have good luck with those.

See this chart for lancet sizes.  Keep in mind that the lancet has nothing to do with the meter.  You do not have to use the same brand of meter and lancet.

The larger the number, the smaller the needle point.  The smaller the needle point, the harder it is to get enough blood but the more comfortable it will be for your cat so you can see that it is a trade-off. However, contrary to what you may think, most cats don't even feel the lancet stick.   I think they 'feel' the nervousness of the human even more!  What bothers them the most is the restraint and sometimes the noise of the lancet pen.

Most people like to use a lancet in the 28-29 gauge range especially when first starting out since it can be frustrating enough to get blood without having to deal with an ultra-fine lancet.

Some people like to use an even larger lancet (25 - 27 gauge).  They are happier with the blood flow and their cats don't seem to mind the larger size.  Other people have had great luck with the lancets that are much finer - more in the 31-33 gauge range.  It all depends on how good of a 'bleeder' your cat is.

You will have to experiment to see what size of lancet works best for you and your cat.

One example of the lancets that I have used is the Life Scan One Touch FinePoint Lancets (purple ones) which, according to the chart above, is a 25 gauge lancet. (No gauge number is listed on the box but I assume that the chart is accurate.)

I have also used the Life Scan One Touch UltraSoft Lancets  (white ones shown in picture above) which are 28 gauge.

The FinePoint lancets will provide a large enough drop of blood more consistently than the UltraSoft lancets.  You can start with a larger lancet but then move to a smaller lancet once your cat's ears start to bleed easier and you start to get the hang of where to test on the ear.  Many people start to use smaller lancets within 2-3 weeks (or sooner) of learning how to home test.  Or...they need to use the smaller ones right from the beginning because their cat does not favor being poked with the larger ones.

Most meters come with 10 lancets but they vary in size depending on the company.  I notice that the One Touch Ultra kits come with the UltraSoft (28 gauge) lancets which may - or may not - prove to be too frustrating when you are first starting out.  You can try them but if you are unable to get enough blood with the ultra-fine lancets (28g), you will have to purchase some larger ones such as the OneTouch FinePoints (25g).

Each meter kit should also come with a lancet device (lancet 'pen') that you can adjust to give a deeper or more shallow penetration of the lancet.  For instance, the One Touch Ultra meter comes with a lancet device that has 7 settings with the largest circle corresponding with a greater depth of penetration.  I found that setting it on the fifth setting (with the first setting being the smallest circle/less penetration) gave the most consistent results.  Setting it on the fourth also worked, but not as consistently.

Some people prefer to 'free hand' the lancet. In other words, they do not use the pen but, instead, they just hold the lancet in their hand and poke their cat's ear that way.

Testing your cat:

Be sure to test yourself first so that you become familiar with the use of the glucometer - especially the way the strips 'sip' up the blood drop.

The most common mistake that I see people make is that they do not hold the ear gently but firmly against the tip of the lancet pen.  Instead, they let the ear fall away from the pen.  If this happens, the lancet will not penetrate the ear.

Vein location - notice the vein (red line) running along the perimeter of the ear:

Aim for the shaded area shown here:

Here is a pictorial webpage that demonstrates the testing procedure.  It is outdated (2001) with respect to meter brand and the comment on blood drop size. (Thankfully, the newer meters do not require a 1.5 uL drop.) 

You will find that there are several different opinions and techniques recommended for the testing procedure and, with time, you will figure out which ones work best for you and your cat. 

For instance, the pictorial page linked above shows the person approaching the cat head-on (in order to test the inside of the ear, versus the outside) which I find makes many cats nervous.  They tend to want to back away from the person and so I would much rather stay behind them as described and shown below. 

However, as the author of this page points out, there is minimal hair on the inside of the cat's ear which may be an important consideration when testing a long-haired cat.  Long hair can interfere with the blood drop formation.  Vaseline may help with the formation of the blood drop on these cats.

This page also discusses the use of warming devices for the ear which I have never tried.  Maybe if I had warmed the ear on my test subjects discussed above, I would have had better luck getting blood the first or second time.

Be aware that if you do not have anything against the ear other than your own finger, you may stick yourself especially if using a lancet pen versus free-hand.  As shown in the third movie below, a small cotton ball or tissue can be used to protect your finger.

Here is a movie  that  demonstrates the testing procedure.  This movie shows the operator using a lancet pen.

This second movie, located here, shows the operator using the lancet 'free-hand' - without the pen. 

A third movie is located here.  This movie shows the veterinarian using a 25 gauge needle instead of a lancet.  I do not recommend this method.  A 25 gauge needle is overkill and will cause more trauma and pain for your cat than is necessary - especially since the newer meters do not require a large blood drop.

The first movie shows the demonstrator using a warmed rice sock that is applied to the ear. Some people like using this method (the warmth increases the blood flow to the ear) but I find it cumbersome and annoying to have to use one more item when testing a cat. Do what works best for you.

After you have poked the ear with the lancet, you may need to 'milk' the blood up to the punctured area for just a couple of seconds. 

These movies show the patients being star pupils although Punkin's owner mentions that he was not this good at the beginning of the testing.  The cats in these movies are minimally restrained but, in reality, not all cats are this good about testing.  Most of them, however, do improve with time.

It is very important to be patient and move slowly and calmly.  Also, the best time to try this procedure for the first time is when your cat is sleepy.  Keep in mind that there is a learning curve for both of you and the less nervous you are, the better off both of you will be.  Rest assured that the procedure will most likely get easier as you polish your skills so please do not get discouraged early on in the learning process.

When first starting to test a new patient, I click the pen several times around the cat's ear to make sure he gets used to the noise.  Depending on the cat, I may or may not poke him in that first session.

When first testing very skittish cats, I simply lightly restrain them and click the pen a few times - without poking them - and then feed them a treat and let them go.

You do not have to get a test on the first try or even on the first day.  Most people are not successful on the first day.  Give it time and try again later that day or the next day.

Offering the cat his favorite treat in conjunction with the testing may help keep him calm and persuade him to view this procedure in a more positive light.

Baby steps and positive reinforcement (treats) are very important when approaching any type of training.  Keep in mind that first impressions are lasting ones so there needs to be a balance between being gentle but firm with your cat.

Although certainly not necessary, it may be easier on your nerves if the first test is done under supervision at your veterinarian's office.  You can also check in with the Feline Diabetes Message Board to see if there are any members living near you who can help you learn how to home test.  There are many wonderful members of this board who are spread all over the world and who are willing to help a 'newbie' learn how to home test. 

Everyone has their preference when it comes to methods used to handle their cat and every cat also has their own idea of what level of restraint they will tolerate.  The least amount of restraint that can be used to get the job done is obviously going to make this less stressful for both of you.  If you can test them, unrestrained, while they are just hanging out on their favorite chair, that is optimal.

Please note that in the following pictures the test strip should already be in the meter but I did not have any at the time these pictures were taken.

The method that works best for me when testing a fidgety cat, is to kneel on the floor with the cat between my knees.  We are both facing the same direction and there is very little firm restraint involved. I just try to prevent the cat from going forward.  I am right handed so it is easiest for me to test the right ear but it is best for the cat to alternate between ears to keep one from getting sore. 

I use gentle pressure with my left hand on the left side of the cat's head to, hopefully, keep him from shaking his head while the blood drop is forming.  I hold the right ear with my left thumb and index finger and my right hand handles the lancet pen.  It is easiest for me to test the outside edge of the right ear but alternating between the inside and outside margins of each ear is optimal.  (Again, please note that the test strip should already be in the meter at this point.)

Testing Calvin's right ear with gentle          Testing Calvin's left ear while restraint.                                                     bracing his head.

The blood vessel runs along the margin of the ear.  Aim for the upper outer (or inner - toward the other ear) edge of the ear anywhere from half to three-quarters of the distance up the ear from the base toward the tip.  (See pictures above where I marked the ear with a pen.)

A tricky issue to contend with is the cat's instinct to shake his head during those few critical seconds when you are waiting for the blood drop to form.

After the lancet is used, I lay it down but continue to gently hold onto the ear and keep a few fingers of my left hand on the left side of his head to prevent him from shaking off the forming drop of blood.  Of course, if he is allowed to do so, the drop of blood will go flying and you will have to start over again. 

If a drop has not formed quickly, you can try to 'pump' the blood into the puncture area with your right hand.  This involves a gentle squeeze and release, squeeze and release just below the puncture site.  Another technique involves gently 'milking' the blood up the vein from the base of the ear.  This whole process takes about 5 seconds or less.

With the One Touch Ultra meter, you have 2 minutes to fill the test strip with blood once the strip is inserted into the meter so don't insert it too soon.  Insert the strip after the cat is in place and ready to be tested.  Two minutes is generally plenty of time but if the meter 'times out' simply remove the test strip and re-insert it.

Once you have a large enough blood drop, touch the tip of the strip to the edge of the blood drop so that the strip will sip the blood into its chamber.  Do not try to 'scoop' or 'scrape' the blood off the ear and onto the test strip.  It must be drawn up by the test strip via capillary ('sipping') action. 

The most common problem that I encountered when first starting to test cats with the glucometer was not getting the test strip confirmation window filled.  When this happens, the One Touch Ultra meter will read Er5 (error message) after the 5 second countdown.  You will then have to get a new strip and start again.  If the blood drop was too small and all of the blood has been drawn up by the test strip - but it is not enough - do not try to get more blood from the puncture site and reapply the test strip to the ear.  That will not work.  As soon as blood enters the strip, the meter starts counting down and adding more blood at this point is futile.

Try to make a habit of watching the test strip window as you are touching the strip to the drop of blood. If your blood drop is large enough, this will ensure complete filling before taking the strip away and will result in a successful sampling.  With a bit of practice, you will also learn not to 'jump the gun' and apply the test strip before you have a large enough blood drop to fill the confirmation window.  If the drop looks too small, be patient and try to gently 'pump' or 'milk' the blood into the puncture area as discussed above.

After the test strip is filled, lay the meter down and gently hold off the puncture site with the cotton ball that you were using to protect your finger.  Necessary holding times will vary but usually 10 seconds or less will be sufficient.

Please be forewarned that you may want to cry and throw the meter when first attempting to test your cat's blood glucose!  There is definitely a learning curve associated with this procedure - for both you and your cat - and the frustration level can be very high initially.  Take a deep breath, stay calm, keep a sense of humor, (drink a glass of wine...eat some chocolate......) and accept the fact that it may take you many tries at different times over the span of a few days to start consistently getting samples.  The calmer you are, the better off your cat will be. 

Do not get discouraged if the first few times do not go well.  If success has not been met after 2-3 sticks (or if the cat is very nervous, after only 1 stick) feed him the treat you have standing by and let him go.  You can try again in a few hours.  You do not need to master this on the first try! 

As already mentioned, a group of very caring and knowledgeable people can be found on the Feline Diabetes Message Board.  They can often talk you down off of the 'ledge of frustration' that comes along with learning how to home-test.  These folks are not veterinarians but many of the members have a great deal of very practical experience in dealing with feline diabetes.

Managing a cat with diabetes can be very overwhelming, to say the least, and communicating with others who are faced with the same issues can be very helpful.  As with any online group, be sure to do your homework and keep in contact with your veterinarian.

Conclusion

While writing this webpage, I decided to see what information is available on the internet with respect to feline diabetes.  I was quite disturbed to see so many authors of the various websites, and posters in chat groups, still continuing to recommend a high complex carbohydrate/high fiber diet. A very critical point is being missed:  Cats are obligate carnivores and a high carbohydrate diet is detrimental to their health, in general, and will make diabetic regulation much more difficult and diabetic remission (no longer needing insulin) almost impossible. 

Also, high fiber diets run counter to a cat's natural diet and recent research has shown that high fiber diets do not favorably impact a diabetic cat like that observed in a diabetic dog or human.

Fortunately, there has been a great deal of focus on feline diabetes in the past couple of years so when you are searching the internet, be sure to pay attention to the date on the webpage for the most recent information. 

The "Catkins" diet (high protein, moderate fat, low carbohydrate) is in and the illogical high carbohydrate/high fiber diets are, thankfully, out.