Obesity in Cats

Article courtesy of The Pet Center.com

Ever wonder what to do about your overweight cat? Obesity in cats is very common and can predispose the cat to diabetes, Hepatic Lipidosis and arthritis. Overweight and actually obese cats outnumber cats of normal weight and are being seen more and more commonly by veterinarians for various disorders. Weight loss plans in cats needs to be approached very carefully. This page will help you determine what to do about overweight cats so that your kitty won’t have to be encumbered by obesity.

There are more cats than dogs in the USA at this time. And 40 percent of those cats are considered to be obese! Only 5 to 10 percent of all cats can be classified as only slightly overweight. In recent years Feline Diabetes Mellitus (diabetes) has become almost a daily diagnosis in animal hospitals all across America. Our cats are at risk for a number of obesity related disorders. Documented research indicates obese cats are far more prone than cats of normal body weight to Diabetes, arthritis and a very serious disorder called Hepatic Lipidosis. And the 40 percent obesity figure seems to be growing.

So what is happening that predisposes our domestic felines to a life of sedentary obesity?

The answer is multifactorial but to simplify, just remember this… any individual mammal (dog, cat, horse, human, etc.) will gain body weight if it consumes more calories than it burns as fuel for energy. That’s pretty simple, but true. In Nature, food acquisition has never been a sure thing for any creature… not for canines, felines or humans. So food acquisition has always been accompanied by physical exertion to capture (or cultivate) and consume the food. It is only in recent times that the unnatural situation of food excess, readily acquired and consumed with little accompanying physical exertion, has become a way of life. We humans have figured how not to have to do all that work of capturing and cultivating to build up stores of food.

Through agricultural expertise we have learned how to grow food and raise livestock and to have those food sources readily available and in abundance… just in case we get hungry! We learned how to refrigerate, dry, preserve and store foods in large quantities that assured us we would not have to endure long and unsuccessful hunting forays nor suffer through famines. We have created the very same food acquisition assurances for our domestic cats. They, as we, no longer have to hunt to survive.

It’s interesting that our pets have mirrored our own tendency to have trouble with weight control. The major difference, though, is that we humans have complete control over what our pets eat and how much they eat. Unless your cat is sneaking into the fridge and making ham and cheese sandwiches late at night when no one is around, the only way they get to eat is when YOU place the food in front of them.

Every veterinarian has repeatedly heard a serious minded cat owner state “I know you think she’s overweight, Doctor, but it isn’t from the food! She hardly eats a thing.” Well… is the pet overweight from high calorie air? Maybe it’s the water… or from laying on that couch all the time. That’s it! The couch is making the kitty fat, not the food. Seriously, far too many pet owners truly believe that food intake has nothing at all to do with their pet’s weight and no amount of counseling will convince them otherwise. If that describes your position, read no further because the rest of this article is all about how to feed the proper food and in the correct quantity so that the cat will lose weight safely or maintain an optimum weight. There will be nothing in this article about the effect of high calorie air, water or comfortable furniture on the cat’s weight problem.

Any cat that is overweight should have a physical exam performed, exact weight measured and blood and urine tests run. It is vital that normal thyroid hormone levels are present and that the cat has no physical or metabolic dysfunction. If the cat is physically normal, other than the abnormal body weight from fat deposition, then a gradual and careful weight loss program can be instituted. First, let’s look at what the causes of obesity are and what we can do to correct OUR mistakes:


THE main reason for feline obesity is the consumption of too much food. Deny it all you want but it is a fact.

What we do…

Many cats are fed “free choice”, which means there is food available all the time and the cat eats whenever it wants. (Pretty unnatural for a true carnivore that evolved as a hunting machine!) Free choice feeding has probably been the biggest single factor contributing to feline obesity.

What we should do…

Feed two to four small portions daily and control the amounts fed so that over a period of time the cat does not gain weight. Many pet owners must downsize what they think is a “normal” portion. A meal for a 175-pound human might weigh 16 to 24 ounces. A seven-pound cat weighs 1/25 of the 175-pound human. So a cat’s meal should proportionally be about 1/25 of a human meal. That comes out to between 0.6 and 1.0 ounce of food per meal for a seven-pound cat… about the same weight as a mouse. Cat owners must stop thinking in terms of “cups of food” and start thinking in terms of ounces of food.


Cats, unlike most mammals, have no carbohydrate-digesting enzyme called Amylase in their saliva. Humans and dogs do and actually begin the digestion of carbohydrate in the mouth. In the intestine,

amylase secreted from the pancreas breaks down large carbohydrate molecules into absorbable smaller units of glucose. Cats have measurably less amylase activity than humans or dogs. Nature did not intend the kitty to be a carbohydrate consumer.

What we do…

We purchase convenient, attractively packaged and preserved dry foods mainly because we can pour it in the bowl and forget it. Dry pet food must have higher levels of flour and sugar than canned foods so that the kibble will stay uniform and not fall apart. Spoiling doesn’t readily occur because of the preservatives so the kitty can eat whenever it wants and we don’t have to prepare cat meals very often. Unfortunately, especially with dry diets, because of the metabolic biochemistry that converts the high carbohydrate content in almost all of today’s commercial cat foods into stored fat, the cat is really at risk for weight gain.

What we should do…

Feed a diet consistent with the nature of a true carnivore… a meat based diet. An ideal feline diet will have a high protein level in the 35 to 45 percent range on a dry matter basis (meaning the percent in the diet when the water has been removed) and moderate fat content with a low percentage of carbohydrate (grains). A multitude of research reports have proven that diets high in protein and fat are most beneficial for carnivores. Cats cannot handle large carbohydrate loads efficiently. After a meal rich in carbohydrate the feline’s blood level of glucose tends to stay higher than normal for long periods of time. They become persistently hyperglycemic and this long term stimulus on the beta cells in the pancreas… the cells that produce insulin… renders those cells less sensitive to the blood glucose. As a result less insulin is secreted to bring down the blood sugar level. Nutritionists call this “down regulating’ of the beta cells; the insensitivity of the insulin secreting beta cells leads to what is termed “insulin resistance”. This scenario is a prelude to diabetes.


We all know how cats crave mice and birds as a food source. A natural source of nutrition for carnivores, mice and birds are a perfect diet for a cat. Did you know that a mouse or a bird is composed of only 3 to 8 percent carbohydrate? And most of that is actually from what the prey was eating and is in the prey’s digestive tract. The rest is water, a few minerals, and mostly protein and fat.

What we do…

Many of us purchase dry cat foods, some with food coloring to make it look like meat and with flour and sugars and preservatives. We buy these dry foods partly because they state that it is COMPLETE and BALANCED for cats and because it is

convenient for us to pour a few days’ worth of food into a bowl for the kitty to eat whenever it wants. Unfortunately, most dry cat food brands are relatively low in protein… especially the less expensive brands that state a grain such as corn as the first (major) ingredient. Another associated problem is the myth that we often feed our cats too much protein. This indefensible myth… that protein causes kidney problems… is totally unfounded and has caused more cats to suffer from poor diets than just about any other cause.

What we should do…

We must feed cats a diet with high percentages of protein and fat and low percentages of carbohydrate (grains) if we expect them to maintain optimum body weights and a proper state of nutrition. Protein is THE key nutrient in a carnivore diet. On a dry weight basis… where the percent of ingredients is determined without any water in the ration… a feline’s diet should contain 35 to 45 percent protein, 40 percent fat, and possibly just a small percentage of carbohydrate. (Remember… a true carnivore needs NO carbohydrate in the diet.) Some nutritionists suggest 25% carbohydrate—50% protein—25% fat. Click the link to see a window that shows how to calculate the dry weight percentages in dry and canned food because if you look at the label of any canned food you will never find a food with high percentages of protein or fat because of the high moisture content of canned food. These low percentages DO NOT indicate a lack of high nutritional content.


All pet foods come with Recommended Feeding instructions. The problem is that these recommendations are NOT absolute requirements even though most pet caretakers think they have to feed their pet the recommended amounts. Most house kept cats, if fed at the amounts stated in the label recommendations, will eventually become overweight. Pay attention to your pet’s body weight (size) and just by simple observation decide if it is overweight. If so, don’t feed so much.

What we do…

Feeding the “Recommended ” daily portions indicated on pet food labels will nearly always result in feeding more calories than the animal needs for an average day’s energy requirements. The carbohydrate excess, unneeded as fuel for metabolism or physical activity, gets converted to fat and stored in the cat’s fat reserves. The odds are very high that if you feed the size and numbers of meals suggested on the pet food label’s feeding recommendations, the cat will end up overweight.

What we should do…

Adjust the amount fed to the cat’s body character and physical activity. If the cat looks and feels overweight… it is! You are feeding too much for that cat’s daily needs for energy for exercise or physical activity; and regardless of what the pet food label’s suggested amounts to feed are, you must feed less than that if the cat is to have a normal (healthy) body weight.


What we do…

We fill the bowls with food and water, clean the litter box, and say “See you later, Kitty, I’m off to work”. OK… let’s say that you can’t help it. You simply are not going to change the food amounts, kinds and portions you have always been feeding your overweight cat. If you are to be successful in promoting weight loss in your cat you will have to increase its’ energy (calorie) burning activities. This is much easier to do with a dog by taking it for a walk or run, throwing a ball, swimming, etc. Good luck going for a run with your cat! Most cats spend most of their time sleeping on the couch, are left alone for long periods of time and really have nothing happening in the home that would trigger a carnivorous hunter’s interest levels. There is nothing to chase, nothing to hide from, and nothing to stalk and run down. There is nothing else to do but to take cat naps!

What we should do…

To assist in improving the kitty’s physical activity, you can add some interactive play toys to the cat’s environment. Consider adopting a friendly and playful cat from the local shelter so the solitary cat has “someone” to interact and play with. Many people believe two cats are more fun to have and more entertaining and no more trouble than a single cat. You can also buy toys that simulate an escaping prey and that really interest the cat in play behaviors. Cats can be exercised but you may need some imaginative toys and ideas to get the job done. PetFoodDirect.com has a good selection of cat toys.


Cats, unlike us humans, obtain food satisfaction less from carbohydrate than they do from protein intake. Give them a high protein mouse and they are as happy as can be. One mouse would make a good meal for an average sized cat. A typical mouse is made of 20% Protein and 9% Fat and lots of moisture. And now that you know that the cat is a true carnivore, that its metabolic pathways have been set by natural evolutionary processes to efficiently utilize meat protein as a major component of the diet, you understand why a carbohydrate rich diet simply does not make sense for felines. Cats are not plant-based grazers; they are hunters of other animals and to reach an optimum state of health they must comply with what nature programmed them to be. There are no vegetarian diets for cats. No matter what your own personal preference is regarding the ingestion of meat, by Nature’s own rules the cat requires meat in its diet. One small aspect of this need for meat is the cat’s requirement for ingesting preformed Vitamin B12 (Cyanocobalamin)… preformed in another non-feline mammal.

As the cat’s caretaker, you have complete control over what your cat eats, how much it eats and how often it eats. Do not worry about the teeth and gums “not having some abrasion to clean off the tartar”. Cats being fed soft meat-based diets have
far fewer oral health problems than those consuming dry, grain-based diets. Other good dry food products will demonstrate protein levels above 30 percent and fat levels above 18 percent in the Guaranteed Analysis table on the pet food label. Usually these diets are the “Growth” or “Kitten” diets… and these formulations can be fed for life in a healthy individual that does not require a therapeutic diet. If you still fear the erroneous myth about “too much protein” being “bad” for cats or that protein “causes” kidney damage, you really need some facts. There are numerous documented reports that will allay your fears and will update you on correct research. The myth about protein causing kidney trouble was extrapolated from research done on rodents many decades ago; the myth developed a life of its own in spite of being refuted by proper research on cats.


Getting an obese cat to lose weight needs to be done gradually… no crash diets allowed! Cats have a unique metabolic response to fasting and whenever a feline’s food intake is rapidly and markedly depressed, a serious and potentially fatal disorder can occur called Hepatic Lipidosis… (fatty liver).

One of the reasons for the success of a high protein diet for feline weight reduction is the importance of an amino acid called Carnitine. Carnitine is present in good quantities in muscle tissues, but found in miniscule amounts in vegetable matter. This amino acid plays an essential role in the uptake of stored fat reserves and conversion of fat by the liver back into glucose. The ability to mobilize fat tissue to be used as glucose for energy (and for subsequent weight loss to be accomplished) requires Carnitine in the process. Supplementing a cat’s diet with L-Carnitine in amounts approximating 250 to 500 mg per cat per day will aid in mobilizing fat into glucose and will improve the health of a cat that is on a weight loss program.


The Plan

First, your veterinarian needs to do a thorough physical exam, blood chemistry profile including Thyroid hormone evaluation, and record an accurate weight for the cat. Then you should gradually… over a period of three to four weeks… add

greater and greater proportions of the suggested feline weight-loss diet. Mix the new diet with the old, slowly decreasing the percentage of the old diet and increasing the percentage of the new one. Pay close attention to how much the cat is eating every day. When the cat acclimates to the improved, high protein diet (fed in small amounts frequently during the day), reweigh the cat at four-week intervals. If there is no weight loss at all, or even some weight gain, the amount of food you are allowing is simply too much. You may be thinking in human-sized portions, not feline. Remember the mouse. Every three to four weeks reweigh your cat on the same scale each time so that accurate weight measurements are done. A fifteen-pound cat should not lose more than half a pound in four weeks. (Remember the Hepatic Lipidosis problem!)

Always be observant and report to your veterinarian any time a cat stops eating for two or more days. (That’s one of the subtle problems with the “free choice” method of feeding. We often do not notice that the cat’s food dish is still full until the cat is well into a fasting mode. When cats are sick the first clinical sign is often a loss of appetite; so a non-interactive, free choice feeding protocol provides less information to us than an interactive portion controlled feeding method.)
Any cat that hasn’t eaten in three days is in trouble! Seven days of fasting actually impacts the cat’s immune system.
Once you have established a feeding plan that induces gradual weight loss over a period of months the cat will reach a point where weight maintenance occurs. At this optimal weight the cat should not “look fat” nor “look skinny”. You’d be surprised how much more active and alert the cat will be at an optimum weight. You have successfully avoided the probability of Diabetes, arthritis and Hepatic Lipidosis. Your cat will probably live a few extra years and have a much better quality of life… and that will make you happy, too!