Obesity in Cats

What is obesity?

Obesity is an accumulation of excess body fat, which leads to excess body weight. We can measure weight on a scale (in pounds or kilograms) to determine if a cat is overweight or obese. Measuring body weight is easier than measuring body fat.

Cats are considered overweight when they weigh 10% to 20% above their ideal body weight, and considered obese when they weigh more than 20% above ideal body weight. In North America, obesity is the most common preventable disease in cats. The 2022 Association for Pet Obesity Prevention survey reports that 61% of cats (and 59% of dogs) are overweight.

What are the risks posed by obesity?

Obesity is a chronic inflammatory condition that can shorten a cat’s life and predispose it to diseases like diabetes mellitus, orthopedic conditions, or cancer. A 2.8-fold increase in mortality has been shown in obese cats (8-12 years old) compared to lean cats. Studies in dogs show that being even moderately overweight can reduce life expectancy by nearly two years. It’s reasonable to expect similar results in overweight cats.

In the past, fat stores in the body were considered relatively inactive tissue, simply holding excess energy (Calories) and adding to body mass. However, scientific evidence now shows that fat tissue is biologically active. Fat cells secrete inflammatory hormones and create oxidative stress on the body’s tissues, which contributes to several diseases. The new approach is to think of obesity as a chronic, low-level inflammatory condition.

Compared to lean cats, overweight and obese cats develop an increased risk of the following problems:

• Cancer
• Diabetes mellitus
• Heart disease and hypertension
• Osteoarthritis and faster degeneration of affected joints
• Urinary bladder stones
• Anesthetic complications

Obese cats who stop eating are at significant risk of developing a potentially life-threatening liver condition called hepatic lipidosis. Other potential complications of obesity in cats include skin and coat problems and difficulty fighting infectious diseases.

How can I tell if my cat is obese?

The first step in helping an overweight or obese cat is to recognize and acknowledge that there is a problem. Unfortunately, we are inundated with images in the media of overweight cats, making it challenging to understand what good health and a fit body shape looks like. Your veterinarian and veterinary healthcare team can assist by providing an assessment.

You can assess your cat’s body condition at home by checking how much fat they have covering their ribs and comparing that to the feel of different areas of your hand. Start by feeling the cat’s ribs just behind their front legs.

• If the ribs feel like the flesh covering the back of your hand, your cat has a good body condition.
• If the ribs feel like your knuckles, or stick out like knuckles, your cat may be too thin.
• If the ribs feel more like the fleshy part of the palm of your hand, your cat may be carrying too much weight over the rib cage.

This hand comparison is also a good way to measure weight-loss progress between formal weigh-ins at your family veterinary clinic.

Your veterinary healthcare team can calculate an ideal body weight to use as a target. Still, it is essential that they also conduct regular assessments to ensure progress is being made toward an improved body weight and body condition. Most veterinary practices use a body condition scoring system on a scale of 1-5 (where 3 is ideal) or 1-9 (where 5 is ideal).

How do I adjust my cat’s meals to help her lose weight?

It is not appropriate to simply reduce the volume of your cat’s current food, because this approach could result in deficiencies of important micronutrients over time. Once you have identified that your cat is overweight or obese, work with your veterinarian and healthcare team to select an appropriate diet and adjust feedings for weight loss. The most efficient way to do this is by using a calorie-restricted therapeutic diet, a specific portion, and a specific meal frequency.

There are several commercial kibble and canned veterinary-formulated diets designed for safe weight reduction in cats. For pet owners who wish to feed a calorie-restricted homemade diet, it is important to work with a veterinary nutritionist who has experience using formulation software so they can customize a balanced recipe.

Once the new food has been selected and specific portions are determined, it is critical that you are consistent with feeding – both portions and meal frequency. It is also important not to go overboard with extra snacks. Treats or snacks should comprise no more than 10% of your cat’s daily calorie intake. For example, if there’s a target of 300 Calories (kcal) per day, the cat should have 270 kcal coming from a recommended diet and 30 kcal from recommended treats or snacks.

Monthly weigh-ins are important for successful weight loss and to keep everyone accountable. It is essential to verify weight loss to ensure that it is not too fast or too slow, and to determine when your cat has achieved a healthy body condition. It is also recommended that you incorporate a physical rehabilitation consultation and rehabilitation therapies into the weight loss plan for successful weight loss.

For more tips on reducing your cat’s weight, see the handouts “Creating a Weight Reduction Plan for Cats” and "Exercising Your Cat for Weight Loss".

What happens when my cat reaches the weight-loss goal?

Once ideal body weight and condition have been achieved, it is important to maintain that weight. With guidance and support from your veterinary healthcare team, you can find an appropriate maintenance food, calorie goal, and daily portions for keeping your cat’s lost weight off.

Portion control is critical at this stage to avoid regaining weight, and that applies to both food in the bowl and treats. After so much hard work, a relapse into obesity would be disappointing. Some cats, especially those who exhibit begging behaviors and are less active, may benefit from remaining on a therapeutic weight-loss diet with slightly higher meal portions for maintenance. Your veterinary team can guide you through this process. The benefits of normalizing body weight and condition make the effort well worth it.