Effect of sterilisation on body weight, metabolic rate and glucose tolerance of domestic cats

This short post is based upon a study published online in March 1997. The concern is quite a well discussed topic, that of domestic cats putting on weight after they've been neutered (males) or spayed (females). I am only able to see the study's summary.

Image: MikeB using Canva. Feel free to use it but please credit me and link back to this page.

This study found that "the castrated males gained more weight as fat than the sexually intact males". And "the neutered males gained significantly more weight than the entire males".

Further, "There was a significant increase in daily food intake after neutering.".

Neutered males gained weight faster than entire (unsterilised) females.

The scientists also said that "Spayed females underwent a significant decrease in fasting metabolic rate". I take this to mean that the spayed female cats had a slower metabolic rate when they were not eating i.e. fasting. It is not stated in the study but it would seem reasonable to conclude that with a lower metabolic rate there is a greater chance of fat being stored because less energy is being used and therefore the food is being burnt up at a slower rate.

They found that there was no or little effect from sterilisation on glucose tolerance. I take that to mean that there is no impact on domestic cats in terms of a predisposition towards Type II diabetes but that is my personal interpretation and it is not stated in the study.

The term 'gonadectomy' is often used by scientists to mean the removal of female testes and the female's ovaries. In other words, sterilisation of both sexes of cat.

Comment - my views

The advice given by veterinarians is to modify your male and female cats' diet after the neutering and spaying operations. I think the operation will affect different cats differently. My cat did not put on weight and was always relatively skinny and only now when he is in middle age is he putting on a little bit of weight. I delayed his neutering operation as long as possible but was pressured by the veterinarian to have it done as soon as possible. I resisted that pressure.

Extruding penis

There is another study online which says that neutering a pre-puberty male cat can leave the cat unable to extrude his penis which would be a scientific way of saying having an erection! I'm not sure this is true although the study was completed by a PhD student. She said that 100% of male cats neutered before puberty were unable to have an erection. I don't believe that at all. 

I have first-hand evidence because my cat gets boners all the time and he was neutered after puberty but there may be an issue here is to whether you neuter a male cat before or after puberty which is about seven months of age in order to allow the male cat to retain some normal malfunction and appearance. In this instance I'm talking about the facial appearance specifically the jowly, square, larger face of the intact male tomcat.

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P.S. please forgive the occasional typo. These articles are written at breakneck speed using Dragon Dictate. I have to prepare them in around 20 mins.

Study: Effects of neutering on bodyweight, metabolic rate and glucose tolerance of domestic cats. Link to the study: https://doi.org/10.1016/S0034-5288(97)90134-X.

The key to losing weight both for owner and cat!

Important note: this is not a lecture. I have no right to lecture anybody. I'm just passing on what I believe as it may help somebody. If it helps one person so much the better. If it helps one cat the same benefit applies. Everyone should have the courage to pass on what they learn if they believe that it is useful to others. Note 2: It is very satisfying to lose weight and maintain a correct BMI. That's a motivator and you'll feel better and good about yourself.

After years of managing and stabilising my weight as an old man (going on 74) and avoiding a pot belly, I think, this morning, that I have figured out the key in one sentence to losing weight and stabilising it. And this key must also be applicable to the domestic cats that we look after them. 

It is as simple is this: you have to feel hungry and you have to feel that hunger for an hour or two a day daily before you eat. And that should apply to every meal you eat. If you use that trick - and it requires self-discipline to quite a high level - you will lose weight and eventually stabilise it. Guaranteed. What percentage of people in the West only eat when they are hungry? A very low percentage is my guess.

Pic: Pixabay.

And if your cat feels hungry, they will be less picky. I am not advocating that you starve your cat. Far from it. I'm just advocating that you should ensure that both cat owner and cat go hungry for a while. My belief is that if you feel hungry you are then ready to eat. If you delay eating when you feel hungry you will burn fat. Fat is a good source of energy. If you don't satisfy that desire to eat which you obviously feel when you are hungry the body turns inward and starts to burn fat as energy.

And when you eat you should still feel a little bit hungry when you finish eating. In other words, you should stop eating when you want a little bit more. This, once again, requires quite a lot of self-discipline. There is no escaping the need for self-discipline when losing weight and stabilising weight. But you can't overeat after you have been abstemious in your diet otherwise you counteract all the hard-fought gains.

There is a natural propensity for elderly people to put on weight. This is because their metabolism slows down but they continue to eat at the same level they ate at when they burned more energy and their metabolism was faster. It is about habit formation. If you don't eat until you are hungry and if you delay eating when you are hungry for an hour or so you create a new habit. Little by little it requires less self-discipline but it will always require a certain amount of self-discipline.

We need to impart that self-discipline to your full-time indoor cat who ends up eating for pleasure. We all know that people eat for pleasure which is entirely understandable. I am very sympathetic because I eat for pleasure too. However, the pleasure I get out from not having a big pot belly is greater than the pleasure I get from eating! And that probably, too, is another key to keeping your weight down.

Ultimately, if you enjoy eating more than you would if you were slim then you won't be slim. You will put on weight to the point where you become desperate enough to stabilise it. And this is the irony of being overweight.

People who are overweight often don't keep on putting on weight. They stabilise at an obese level so why not stabilise at a slim level! Stabilising at an obese level requires a certain amount of self-discipline because you aren't putting on weight anymore and therefore you have cut back on what you're eating. Why not lose some weight and then at that point stabilise it by eating a bit less?

But ultimately, if you want to lose weight you have got to be hungry and you've got to get used to being hungry for a short while until you satisfy the urge to eat.

4 cat health problems caused by obesity

There are at least four and probably more diseases and conditions caused by feline obesity. Obesity contributes to arthritis. There is a fourfold increase in type II diabetes in obese cats. Obesity can lead to a dull, unkempt coat because cats can't get to those parts of the body that need grooming. The chances of a cat suffering from hepatic lipidosis are greater if the cat is obese or overweight. Hepatic lipidosis is also called fatty liver disease or syndrome. This disease is also caused by a crash diet ironically. 

Obese cat. Image: Pixabay.

If you want your cat to lose weight then you should do it gently. But please do it! Other factors associated with the onset of hepatic lipidosis include deficiencies in nutrition, diabetes, hyperthyroidism, anorexia as mentioned and diet change as mentioned. In America as many as 57% of domestic cats are believed to be overweight or obese.

On the issue of a poor coat, although I am not a great fan of dry cat food, I can recommend Hills Oral Care. My cat tends to have a nice, high quality coat when he feeds on this commercially prepared food. Of course, he is not overweight and therefore is able to groom himself in addition to which I comb him daily with a very fine comb which he thoroughly enjoys.

In addition to obesity substantially increasing the risk of contracting Type II diabetes, other risk factors include increasing age, physical inactivity, use of steroids in treating other illnesses, male cats and physical inactivity.

Apparently Burmese cats in some countries appear to have a high risk of developing diabetes over other breeds. The two most common signs of diabetes in cats are weight loss despite a good appetite and increased thirst and urination.

Without wishing to preach, there are two ways to get a cat to lose weight which are to feed him or her less and to ensure that she exercises more i.e. is involved in more physical activity. It is easy to deceive oneself as to how much food one is providing a domestic cat.

The reason why obese cats are predisposed to becoming diabetic is because obesity causes increased levels of fatty acids and inflammation which leads to insulin resistance which in turn can lead to type II diabetes.

Feeling your cat's shoulder blades, ribs and spine

Judging by searches on the Internet, there is a concern among some cat owners about the weight of their cat and the fact that they can feel their cat's shoulder blades, ribs and spine. I'm not necessarily referring to feeling these aspects of anatomy at the same time but all three bone structures can be felt when a cat is in good health and not necessarily underweight. The photo shows a slender stray cat. They are often slender because they eat less than domestic cats and move more! This cat is slightly underweight.

Image by Liselotte Brunner from Pixabay showing a slender cat

Shoulder blades

These invariably stick up when a domestic cat is in a certain position. They are quite prominent most of the time in a cat of the correct weight. There is quite a large depression in between them. It's all normal. Obviously there are various degrees of prominence of a feline's shoulder blades. No doubt when they are very prominent the cat is likely to be underweight. But when they are modestly prominent and can be felt by their owner and indeed are visible as well, the owner should not be concerned about their cat being underweight.

Ribs

They should be felt as if covered slightly or lightly by some fat when a cat is of the correct weight. It is notable that there should be some covering of skin and fat to take away some of that definition from feeling the ribs. Under these circumstances the cat will be of the correct weight. If they can be felt quite markedly and if the spine is also overly visible or can be felt too easily then I would suggest that the cat is underweight.

Spine

My cat is about the correct weight. He tends to be what I would describe as "fighting fit". That means slender. He is slender because he is active and does not overeat. I can just about feel his spine when he sits down in the upright position i.e. on his bottom in that familiar pose that we see in ancient Egyptian statues. Also when he is walking around on my lap. This is all normal. You can feel your cat's spine when he or she is within the normal weight range. But you might not which would also be in the acceptable weight range. 

Once again, the amount the definition that you can feel will vary and at one end of the spectrum where the definition is pronounced it is likely that your cat will be underweight. If the spine is visible then it is likely your cat is very underweight.

But the point here is that if you are able to feel your cat's spine by rubbing your hand along it with slight pressure, it does not mean that your cat is underweight. Although it might mean that he is underweight depending upon, as mentioned, the amount the definition of the spine that you feel or how pronounced the spine is. But you can't jump to an automatic conclusion that just because you can feel your cat's spine that he or she is underweight.

The reason why I am going on about this is because I sense that quite a lot of cat owners are concerned, because they can feel these bone structures of their cat, that there cat is underweight. And weight loss is a very general symptom for a wide range of illnesses. Illness leads to lack of appetite and of course lack of appetite needs to loss of weight.

How do I conclude this short post? I believe that if you want to assess a cat's weight you have to look at various visual aspects and the test does not exclusively include feeling for the bone structures mentioned.

Assessing weight

To be honest, I think people should take a commonsense approach to assessing their cat's weight. We all know what an overweight person looks like and we all know what an underweight person looks like. Use that basic common sense to assess your cat in the same way. There are many resources online as well if you are unsure. For example, on another website of mine you can have a look at some photographs or illustrations which may guide you by clicking here.

Senior cats

Senior cats tend to put on weight, the opposite problem. So unless maintaining a good body weight is a problem, senior cat should be on a reduced-calorie diet. There is an obesity epidemic we are told by the veterinarians. Obesity leads to illnesses such as diabetes. If your cat is overweight she should lose weight gradually to avoid fatty liver disease. You can read about that by clicking this link.

Cat Obesity Effects and Management

Some more notes on cat obesity. The first point to notice is that cat obesity is defined as being greater than 15% over the ideal weight (9-12 lbs for a male and 7-10 lbs for a female cat - but cats vary considerably from breed to breed and from individual to individual). I am surprised because 16% over normal weight is not a lot overweight and yet a cat will be classified as obese.

Cat obesity is the biggest problem regarding the feeding of cats in the USA and Western Europe. Apparently, up to 20% of cats in these regions are obese. My late lady cat Binnie was obese at one time so I have first hand experience of cat obesity.

Nearly all cat obesity problems are because the cat eats too much in relation to the lifestyle that he or she leads. By eating too much I mean that the calorie intake is too high. By lifestyle I am particularly referring to the level of exercise the cat partakes in. As usual it is all about how much goes in and how much is burnt off.

There are a lot of charts on assessing cat weight but we don't really need them because anybody can assess whether there cat is overweight. We simply need to use a common sense method. Essentially use common sense and you can feel your cat's shoulder blades and their spine when they are within a good weight range. You should be able to feel your cat's ribs under a layer of fat when they are of the correct weight.

Obese gray cat. Image by Quinn Kampschroer from Pixabay

Problems

Problems that can be associated with an obese cat:

• breathing difficulties - the recent, well circulated story of Meow the 39 lb cat sadly illustrates this problem.
• FLUTD - feline lower urinary tract disease.
• higher risks of failure during veterinary surgery.
• response to infectious diseases is poorer.
• resistance to insulin - development of diabetes.
• the inability of the heart to work harder when called upon (reduced cardiac reserve).
• the accumulation of fat in the liver cells.

Reducing weight

It can difficult to reduce the weight of your cat. I think we all know that. This because:

• we don't see the effect of a diet quickly
• we lose discipline
• our cat pesters us successfully
• cats have specialist diets being obligate carnivores
• cats are less food orientated than dogs
• cats sometimes have a strong preference for a particular food type.

There are various ways to feed a cat. For weight loss there is no secret that the method is lower calorie intake and/or more exercise. The former is probably easier to achieve than the latter. How many calories does a cat need?

The reduction in food intake should not be more than 30% lower than normal (or 70% of normal). It can be dangerous from a health standpoint to try and force a cat to eat a food that he or she does not like. However, feeding a food that he is less keen on, especially at night when you are asleep so don't have to deal with the emotional problems can be successful in my experience. Weight loss should be managed otherwise it can cause fatty liver disease (hepatic lipidosis) which is linked to sustained loss of appetite. Weight loss should be no more than 1.5% of body weight her week. This is to avoid the possibility of a cat developing fatty liver disease which can happen when a cat becomes anorexic.

Bearing in mind that cat caretakers may, and often do, struggle to diet their cat, it is probably sensible to get your veterinarian involved from both the standpoint of advice on a feeding regime and the type of food that is suitable together with the motivation that this may bring to the task at hand.

Apparently as a cat's calorie intake is reduced the cat's calorie requirements are reduced (the basal metabolic rate falls). This would seem to work against the diet being successful. The answer to this problem is to try and encourage your cat to exercise more.

Cats are very persuasive companions. It is difficult to resist their demands for a meal. We need to bite the bullet and to a certain extent be cruel to be kind.

Night time dieting as mentioned above works for me as my cat accepts the fact that I am asleep and won't pester me for food.

Source: Myself and The Welfare of Cats ISBN 978-1-4020-6143-1