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What is Gaining Weight?

In order to properly distinguish when a cat is overweight, we must look at the guidelines for obesity. Typically, obesity is determined when a cat’s body weight is 20 percent over its average weight. It is a metabolic disease that creates problems such as changes in appetite control, energy usage, and low-grade pro-inflammatory state. The frequency of overweight cats is a growing concern in the veterinary world and although it may not seem to be a serious condition on the surface, obesity can seriously degrade your pet’s quality of life.  It is important to note that simply overfeeding is not the only cause for obesity. There may be much more serious underlying causes that need to be addressed immediately. 

  • Diabetes
  • Asthma 
  • Hypertension
  • Congestive heart failure 
  • Hepatopathy 
  • Urinary tract disease 

If you notice that your cat has become overweight, it is quite possible that it is either experiencing one of these symptoms or an easy access to food throughout the day that is far too frequent. Regardless of what you may assume the cause to be, it would be best to get your cat checked out by a vet as soon as possible to rule out any life threatening conditions. Finding the cause of the obesity is the best way to begin reversing the problem. 

While it may seem the best solution would be a “starvation diet” where all food becomes severely limited, trying to simply cut off the cat’s food supply will not solve the problem. This can actually cause serious health problems that would be detrimental to your cat’s life. The best way to approach an obesity situation is with gradual weight loss.

Why Gaining Weight Occurs in Cats

There are two main reasons why obesity occurs in cats: availability of food and an existing internal problem. Either one of these situations, or a combination of both, will cause your cat to put on an excessive amount of weight. It will be difficult to determine what the cause of the obesity is just by sight alone, so it is best to get your feline into a vet for regular checkups in order to resolve the issue efficiently.   

Food Consumption

One of the most common reasons is the availability of food. More often than not, owners will leave a bowl of dry food within reach for their cat to consume at any time of the day. This is known as “free feeding” and it contributes highly to obesity in cats. Just like humans, if there is delicious food setting out, the temptation to eat our feel is quite hard to resist. Even if the cat is not hungry, boredom may be cause enough to approach the available food. 

Underlying Internal Issue

The second reason cats can be prone to obesity is due to an internal issue, such as diabetes or congestive heart failure. This is due to the fact that the extra weight on the cat’s body can place an extra burden on the heart, causing it to fail over a prolonged period of time. Diabetes affects the way that the body produces insulin, which then decreases the regulation of blood sugar. Failure to have these issues addressed can lead to your cat’s death.  Difficulty in moving around caused by issues like osteoarthritis or spondylosis can also lead to a cat gaining weight. Conditions such as urinary tract abnormalities or liver disease will contribute as well.

What to do if your Cat is Gaining Weight

The first and most important thing to do when addressing your cat’s obesity is to take a visit to the vet’s office. There, the doctor will be able to determine the underlying cause of the obesity: whether it is simply over eating, or some kind of internal issue. Once the cause has been determined it will then be up to you to take control of your cat’s habits. 

As mentioned before, do not place you cat on a starvation diet. This will only lead to more serious health issues down the line. According to Dr. McDaniel from Cornell University of Veterinary Medicine, the best thing that you can do is to “aim for perhaps one to two percent loss of body weight per week”. This slow method will help to ensure the safety of your cat while you reduce its overall body weight. Purchasing a small scale would be the perfect tool for aiding in the monitoring of this process. 

For a health condition like diabetes or liver disease, your pet may need to undergo blood tests in order for the veterinarian to assess markers that point to the condition. X-rays and a CT scan or MRI can allow the vet to diagnose a mobility condition like spondylosis.

Prevention of Gaining Weight

Most cases of obesity in cats can be avoided simply with a proper diet and a good amount of exercise. When determining whether or not your cat is on the right weight track, you can use the “Body Condition Score” chart that can be found from pet food manufacturers like Purina. It is a simple process that involves three assessment stages:

Perform a rib check by gliding your hands, palm face down on the fur, across your cat’s rib cage on each side. 

Observe your pet from the side and take note of its profile; does the stomach hang low towards the ground?

Observe your cat from above. If the cat is severely obese, you will not be able to see the ribs, there will be heavy fat deposits over the spine, face, and limbs. Additionally, the stomach will be distended with no visible waistline. 

If any of these steps suggest obesity, then it is advised to visit your vet for further diagnoses. Through careful planning and care, your cat will once again be able to live a full and happy life, free from extra weight. 

As for any underlying internal issues that your cat may have, the vet will be able to help prescribe the required medications to help alleviate the issue and further treat any diseases.

Cost of Gaining Weight

Treatment cost will vary depending on the underlying causes of your cat’s obesity. For example, diabetes treatment can vary from $1000 to $5000 depending on the severity. If your cat is diagnosed with congestive heart failure, the average cost will be $1800.

Gaining Weight Questions and Advice from Veterinary Professionals

1 Year
Moderate condition
0 found helpful
Moderate condition

Has Symptoms

smelly bum

Got a kitten November 2018. He is a siamese calico mix. He was the teeniest kitten ever and over the course of a year he got MASSIVE. He has a big head and big paws but he also has a massive mid section.
He eats twice a day, only 1/3-1/2 cup each portion and he eats good quality food. He rests a lot.. and he used to be more playful as a little kitten.
I'm not sure if hes meant to be big or if there is something else wrong.

its the food too, turns out cats are little hunters and stuffing them with grain sucks, but man do those companies turn waste into fat cats for their fatcat lobbiests

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Lilly Lou
3 Years
Fair condition
0 found helpful
Fair condition

Has Symptoms

Rapid weight gain.

My cat is 3 years old and has a very small frame. I noticed she had been gaining some weight the last couple of months. She does not like to be picked up and held but I do so this morning and I was shocked. Her stomach is barrel shaped, very tight and she is obese. I dont know if she has a physical problem or if it is simply too much food. She is still eating the same thing she has been eating since I brought her home three years ago. She is very active and does not seem to be uncomfortable but she does have episodes of loose stool ocassionally.

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Domestic shorthair
1 Year
Fair condition
0 found helpful
Fair condition

Has Symptoms

Weight gain

My cat hunter is a year old and I’ve noticed he’s been gaining weight a lot quicker than his brother Smokey and hunter has always been the bigger of the two but he’s clearly getting chubby and i just wanted to know what’s the best diet food for him to eat and how to transition him to eating at a certain time or getting him to only eat the new food until the goal is reached?

Dr. Callum Turner, DVM
Dr. Callum Turner, DVM
3320 Recommendations
There are a few different causes for weight gain in cats and if you’re feeding both cats the same you may want to check with your Veterinarian for hormonal conditions or other causes of weight gain; you may place Hunter on a diet (there are many diet foods to choose from in the pet shop) but you need to make sure that the issue is overeating and not due to another underlying cause. Regards Dr Callum Turner DVM

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Domestic shorthair
9 Years
Mild condition
1 found helpful
Mild condition

Has Symptoms


I have 2 cats Mixin & Penney both indoor. Both are quite chunky but active I’ve been wanting to change there food so they can eat more healthy. So switched to a no grain pet food same exactly same brand been doing about 50/50 mix of old food and new food. Although my older cat is a big smarter and knows it’s different so he doesn’t eat and when he does he ends up throwing it up. I don’t want to be hurting my cat but i want him to be more healthier. This is my 3rd day of the food change should I continue it? Thank you

Dr. Michele King, DVM
Dr. Michele King, DVM
1611 Recommendations
If Mixin is vomiting with the new food, it seems that may not be a good food for him. There are many very good quality weight loss foods available that they may tolerate, and cats don't need to be on grain free diets unless they have obvious food allergies. If you aren't sure what food to switch them to, it would be best to consult with your veterinarian, as they know more about your cats, and Mixin is getting a little older, which may impact food choices.

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