As I explained in my previous blog article, obesity is a serious health problem and a growing concern with around one cat out of three which is overweight! In this article, I will explain what the causes and risk factors of obesity are, in order to help you better understand the problem and how to prevent it.

The causes of obesity

Obesity is an excess of body fat, which is generally caused by an energy intake superior to the energy expenditure. This means that your cat is eating more calories than it is burning every day, and there can be several causes to that. Some of the risk factors are linked to your cat and you can’t do anything about it, but you can still be conscious of it: if your cat has several predispositions to being obese you will need to be more careful about its weight. For some of the other risk factors, especially the human-related ones, you will be able to adapt your behavior in order to prevent obesity.

The individual risk factor causes


The most important risk factor for your cats is being neutered. In fact, after being neutered, the hormone alteration in a cat’s body causes an increased need for food intake, which means that your cat will eat more after being neutered. A way to mitigate this effect is to reduce or limit the amount of food available to your cat immediately after neutering. Ask your vet how you should proceed. The age of neutering didn’t have an impact in most studies, except in one that showed an increased risk for cats older than 6 months.


Male cats are at increased risk of obesity. It could be because male cats have a larger body frame and so it is more difficult for the owner to evaluate the body condition of their male cats compared to a female.

Cat age

Cats aged between 2 and 12 years seem to be more at risk of obesity. It’s likely because young cats are more active than middle-aged cats and elderly cats have a natural weight loss.


Several studies reported that non-pedigree cats are more likely to be obese than pedigree cats. Domestic shorthair, domestic longhair and crossbred are at a higher risk of being overweight. As another study showed, cats purchased from a registered breeder had a lower risk to be obese. An explanation for this could be that registered breeders provide information about the diet, cat care, body condition, and environmental enrichment that all play an important role in obesity prevention. Nevertheless, some breeds such as British shorthair, Persian, Maine Coon, Norwegian Forest cats were at a higher risk than other breeds such as Cornish and Devon Rex, Abyssinian, Oriental/Siamese, and Sphynx. However, it doesn’t seem that genetics itself plays a role in this higher risk of obesity: it is more linked to the owner’s perception. In fact, the breeds at a higher risk are described in their pedigree standard as “massive”, “heavily boned” or “well-rounded”, which may lead the owner to consider an overweight cat as acceptable. Likewise, the breeds with lower obesity risk are described as light and elegant, influencing the owner to keep their cat lean.


As it’s more difficult to estimate the body condition of longhair cats because of the fur which makes the palpation and visualization of the cat less evident, owners of longhair cats tend to underestimate the body score of their cat, which result in a higher risk of being overweight.

Other/Anecdotal risk factors

One study reported that cats born during the increasing photoperiod (December to June) were at an increased risk compared to cats born between June and December. Another study showed that cats with a high rate of growth between their 3 and 12 months were at a higher risk of being overweight. Finally, some diseases can cause a cat to be overweight. However, keep in mind that hypothyroidism (which is often cited as a cause for obesity) is extremely rare in cats! To summarize, if your cat is a 5-year-old domestic longhair neutered male, it is at a higher risk of obesity than a 1-year-old intact female Abyssinian! Being conscious of the obesity risk of your cat is important so that you know that you’ll need to monitor its weight. fat-cat-2

The environmental risk factor

Environmental risk factors are the ones on which you can have a direct influence and that are independent of your cat.

Dry food

Cats that are fed with dry food are at an increased risk of obesity. This risk even increases if the cats are fed with always the same food, or only with dry foods and if the kibbles are purchased from a supermarket. The explanation proposed in the studies is that kibbles are a high energy density food, meaning that the cats need to eat only a small amount of it due to the high amount of calories in kibbles. Another explanation is that feral cats normally have a low-carbohydrate diet mainly composed of wild prey: cats are not adapted to use carbohydrates as their primary energy source like it’s the case with today’s kibbles. Additionally, cats tend to eat less when they have a diet rich in water. Feeding a human-grade raw meat diet, feeding raw meaty bones or a home-made diet was protective against obesity. In fact, providing raw bones allows the cats to have a normal chewing behavior and a slower meal consumption which could decrease boredom and stress. Additionally, owners feeding a home-prepared diet are more focused on nutrition and more attentive to the health and body condition of their cats.

Food ad libitum

It seems that cats fed at will are at a higher risk of obesity, which could mean that not all cats are able to regulate the quantity of food they eat.

The way to measure the food

It can sound surprising but measuring the quantity of kibble with a scoop was also associated with obesity. In fact, in a study in which dog owners needed to measure kibbles with a scoop, the inaccuracy ranged from an underestimation of 47% to an overestimation of 152%!

Indoor and inactivity

Surprisingly, being an indoor cat wasn’t always associated with a higher risk of obesity. Several studies concluded that there was no increased risk of obesity for indoor cats. However, inactivity was associated with a higher risk of being overweight.


Like for humans, other possible factors of weight gain are stress and anxiety which can lead to the inability to control the amount of food they eat.


One study reported than when owners gave their cats treats when they “felt happy” with them, the cats were 3 times more likely to be overweight compared to an owner that rewarded their cats with playing or cuddles! As it can be expected, you can see that what you feed your cat can have a huge impact on its weight. That’s why providing an adapted and balanced diet to your cat is very important. fat-cat-2

The human-related risk factor

Finally, the last category of risk factors is the one that is directly linked to the owner. Being conscious of your influence on your cat’s weight is maybe one of the most important things to remember from this article!

Owner underestimation

Underestimation of the body condition by the owner is a major risk factor in obesity, at the same level as neutering! In almost every study conducted, the owners underestimated the body condition of their cat. For example, in a study, 60% of the owners were not able to give a correct body condition score to their cat. This is can be due to several reasons. Firstly, the owner is biased as they are attached to the cat and cannot objectively score the cat. Secondly, it seems that there has been recently a normalization of overweight cats in the media, being described as “cute”, “chubby”, “cuddly”, which could have modified the perception of what a truly healthy body condition is!

Owner awareness

A lack of awareness about the health issue associated with obesity is also a risk factor for obesity. In fact, in a survey conducted in the USA and Australia, a third (32%) of the owners reported that their cat was overweight, but only 0.8% considered that it was a health problem. If the owner is not aware of the health issue associated with obesity they may not act to reduce their cat’s weight. An owner that tends to use “genetics” as a cause of obesity and underestimates their own feeding behavior has more chances to have an overweight cat. Finally, owners of overweight or obese cats tend to avoid these two words to describe their pets and will use euphemisms such as “big-boned”, “a bit chubby” or “pudgy”, which shows that they are trying to minimize the issue.

Misinterpretation of feline behavior

It’s been reported that often when a cat starts an interaction with its owner, the owner assumes that the cat is hungry even if it’s not the case and provides food. The cat then learns that starting an interaction with their owner will result in a reward in the form of food. This means that in fact, owners train their cats to beg for food, while the cat may have been just bored or wanted to play in the first place.

Over-humanization and anthropomorphism

Owners that tend to anthropomorphize their pets are at a higher risk of having overweight pets. In fact, an unhealthy human-animal relationship can end up in inappropriate feeding behavior, which will cause obesity. Examples of inappropriate behaviors reported in studies were: giving treats when the cats are begging because they are afraid the cat might suffer, and overfeeding their cats to express their love for them.

Owner playing with the cat

Owners of overweight cats were spending less time playing with their cats: this could be a risk factor. You can see that obesity is really a multifactorial issue, where many parameters can increase or decrease the risk of your cat to be overweight. You cannot change the individual risk factors of your cat. However, you can have an influence on the environmental risk factors such as the food you are feeding your cats. Finally, your role as the owner is very important in preventing obesity, as underestimation of your pet condition is a major risk factor. The good news is that being aware of the issue is already a big step toward prevention and improvement! In the next article, I will share my tips to help your cat lose weight if it needs to. Sources Larsen, J. A. (2017). Risk of obesity in the neutered cat. Journal of Feline Medicine and Surgery, 19(8), 779–783. N.J. Cave, F.J. Allan, S.L. Schokkenbroek, C.A.M. Metekohy, D.U. 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