Vets explain how to tell if your cat is overweight or underweight — and why it matters for their health

Overweight or “chonky” cats might star in any number of memes and viral videos , but gaining too much weight can put your kitty at risk for a number of health concerns. Excess fat can: Up to 60% of cats in the United States are overweight or obese. But you might not always find it easy to recognize the difference between a larger breed of cat and a cat with obesity.

Here’s how to check your cat’s size under all that fluff, plus a few tips for helping them lose weight safely, according to veterinarians . A healthy weight depends on feline breed and body frame size, and there’s a lot of variation between cats: Some breeds, like the Siberian, might weigh 26 pounds . Others, like the Munchkin, might only weigh 5 pounds .

Body Condition Scoring (BCS) is the best way to check your cat’s weight, says Angela Topf, a veterinarian at The Vets . The BCS chart provides healthy weight guidelines for pet parents and veterinarians by breaking down a cat’s potential weight into several categories: Each score above 5 indicates a 10% increase in body fat, says Julie Churchill , a veterinarian and professor of veterinary nutrition at The University of Minnesota College of Veterinary Medicine. Obesity typically means a cat weighs at least 20% more than their recommended weight based on their breed.

That means if your cat has a BCS score of 7, they have 20% more fat than what’s considered healthy for that cat’s size and breed. However, it’s important to note that BCS is to cats as BMI is to humans. In other words, it’s not always an accurate measurement of obesity.

In fact, a BCS score between 6-9 is considered healthy for certain cats. For instance, older cats often can’t get nutrients from their diet as effectively as they age, so they might need more food to get enough vitamins. This can translate to a higher weight.

Of course, if you’re constantly feeding your cat treats and lots of food, they’ll probably gain some weight . But plenty of other contributing factors can also play a part: Weight gain increases your cat’s risk of a number of health conditions, since extra body fat increases their inflammation levels , Churchill says. An overweight cat has a higher risk of : An obese cat may have a lower activity level, a reduced quality of life , and a shortened life span, Churchill adds.

What about underweight cats? It’s less common for cats to fall under the ideal weight range: A study of 15,659 cats found that only 5. 3% were underweight. That said, an underweight cat has a higher chance of experiencing health risks like malnourishment.

What’s more, rapid weight loss can sometimes suggest medical concerns like viruses, parasites, or cancer. Factors that may raise your cat’s risk of a too-low body weight include: Note: A veterinarian can offer more guidance and feeding recommendations if you think your cat may need to gain a pound or two for optimal health. “First and foremost, you should take your cat to a veterinarian to assure healthy slow weight loss,” Churchill says.

Churchill recommends always checking with your vet before cutting back your cat’s food or switching brands — sudden or major changes to a cat’s diet could lead to malnourishment , “The calories in cat foods can vary widely, so if you change foods, one cup likely will not be the same amount of calories,” Churchill says. What’s more, losing weight too quickly can raise your cat’s risk of diseases like fatty liver , Topf says. “Weight loss should take place over weeks to months, at a rate of 0.

5%-2% of their starting weight per week,” Topf says. For instance, a 20-pound cat can safely lose just under half a pound a week, but no more. Your veterinarian may recommend the following tips to help your cat lose weight: Important: Call a vet right away if your cat doesn’t want to eat or drink, or begins to lose weight rapidly.

This can suggest anything from environmental stress to a number of health concerns — some of which may be life-threatening. Keep in mind, too, that going without food for just a few days can make your cat very sick. There’s more to weight loss or weight gain than switching or limiting your cat’s food, which might do more harm than good without guidance from a vet.

If your cat seems a little heftier than usual, a good first step involves doing a weight check with your veterinarian . Your vet can recommend treatment for any underlying health issues, like arthritis or diabetes, and develop the purrfect (pun intended) health plan for your kitty to bring them to a healthy weight. .