You love your cat. And she loves you back (doesn’t she? when she’s not silently judging or simply ignoring you?). But if your favorite feline is looking a little portly lately, it may be time for some tough love.

“An easy way to tell if your cat is at a healthy weight is to gently feel his spine and ribs,” says veterinarian Julie Horton, DVM, medical director at the ASPCA’s Adoption Center in New York. “Softly press down on his spine and ribs, and, looking down from above, you should see a waist — an indentation behind his ribs and before the hips.”

A plump cat is more prone to a number of health issues, including diabetes. “Diabetes in cats tops the list of health problems associated with obesity,” says veterinarian Ernie Ward, DVM, founder of the Association for Pet Obesity Prevention. And, he says, “It’s preventable.

Ward calls diabetes “the food bowl disease.” “It’s because we fill up their bowls and give them treats.” If your kitty is tipping the scales, it’s not alone. “Fifty-eight percent of cats in the U.S. are overweight, and what we are seeing is that cats are getting heavier than ever before,” says Ward.

Fat cats also face a shorter lifespan and a higher risk for degenerative arthritis (too much weight puts a strain on a cat’s joints), high blood pressure, heart and respiratory disease, kidney disease and many forms of cancer. And if they do get sick, medical care can be expensive, says Ward.

“It’s something that most people don’t think about until it’s too late. All of this can be avoided by monitoring our habits when it comes to feeding out cats.”

Related: 8 Common Cat Feeding Mistakes to Avoid

What, and how much, should cats eat?

Cats are carnivores; they require protein to survive. “The good news is that there are a lot of healthy options available from pet food supply stores and in grocery stores,” said Ward. When buying cat food, look for some form of meat (which includes fish and poultry) as the first ingredient.

Figuring out how much to feed your cat is a bit trickier. Some bags of cat food have charts with recommended serving sizes (cans of cat food usually don’t) — but don’t take those charts as gospel.

“Whether you are feeding your cats dry, wet or a combination of both, you should talk to your cat’s veterinarian about how many calories your cat needs each day,” says Horton. “That amount depends on the size and age of your cat.” A larger cat, like a Maine Coon, eats more than a smaller domestic short hair, for example. Horton recommends choosing food intended for you cat's age. 

The majority of cat food brands, both dry and wet, are designed for four stages. These are:

  • Kitten (up to age 1)
  • Adult (ages 1 to 6)
  • Mature (ages 7 to 11)
  • Senior (ages 11+)

The nutrients differ from stage to stage. “Kittens need more protein and fat in their diets than older cats,” says Horton. 

“As your cat ages, you should transition from one type of food to another," she says. "Gradually introduce the new food when your cat matures from one stage to the next. I would do this over a period of five days. Mix some of the new food into the old, and then gradually add more of the new food.”

Once you know how much to feed your cat, if you're using dry food, "keep a measuring cup in the bag to measure how much food you are giving,” suggests Ward.

Most veterinarians believe cats should be fed twice a day, and that after the cat walks away from the bowl, you should pick it up and clean it. Don’t let your cat graze. And of course, make sure he has fresh water in his bowl at all times. (Whether you opt for a fountain with running water depends on your cat’s preferences. Some cats prefer bowls with moving water and other cats don’t.)

Ward gives his cats a midnight snack. He just makes sure that he doesn’t go over the allotted calorie count in a day.

Opt for healthy treats

Just because cats are carnivores doesn’t mean they can’t benefit from nutrients found in vegetables. Ward suggests feeding your cats cooked or raw carrots, broccoli, spinach and other dark, leafy vegetables.

“As an alternative, my favorite snack foods for cats are salmon and sardines. Rich in healthy omega-3 fatty acids, these cold-water fish are a tasty treat most cats love. Be sure to reduce their regular diet if you add them so you don’t overfeed your cat.”

Multiple cat homes

It’s not uncommon to have a home with one fat and one thin cat. Never feed cats side-by-side. One will tend to scarf down his food and then push the other slower eating cat away to eat that meal too. If you do have one cat that eats quickly and then hones in on the other food bowls in the house, feed your cats in separate rooms.

Related: Introducing a New Cat to Your Home

The same advice can be used in multiple pet homes. Dogs usually eat faster than cats and some tend to eat the cat’s food after finishing their own food. If this is the case in your home, feed your pets in separate rooms and always pick up the food bowl after the slower eater walks away. If there is any food left in that bowl, pick it up and clean it; otherwise, the aggressive cat or dog that finished first will go for a second helping.

Upping your kitty’s exercise

Cats sleep an average of 16 hours a day and spend most of their awake time eating or lying in their favorite warm or sunny spot. So adding a bit more exercise to their day can make a difference.

One of the easiest ways to make sure your cat gets some exercise is to find a toy that your cat will chase around the house. Pretty much all cats love to chase laser pointers — just make sure you don’t shine it in his eyes. Playtime isn’t only for exercise, it’s great for bonding, too.

Related: Cat Toys: Which Ones Are Safest?

You can also purchase cat climbing towers and shelving for cats to climb on. Cats love lounging on high spaces from which they can look down. And of course, climbing up and down is good exercise.

An empty cardboard box is another favorite cat “toy.” Cats enjoy jumping in and out. Just make sure there is an opening so the cat can always get out of the box.

Some cat owners have taken to walking their cats outside on a harness. If you do, make your cat is up-to-date on his vaccines. And test the harness before you go outside. “Make sure it’s secure because cats can easily get loose, run and hide or worse go into traffic and get hurt,” says Horton. The ASPCA has tips on teaching your cat to walk on a leash.

Michele C. Hollow writes about pets and wildlife. She is an award-winning journalist who has written for The New York Times, The New York Daily News, FamilyCircle.com and other leading publications. She blogs at Pet News and Views. One of her cats has learned to open the cabinet door where the cat food is kept. The cats also know where she hides the laser pointer. 

Michele C. Hollow writes about pets and wildlife. She is an award-winning journalist who has written for The New York Times, The New York Daily News, FamilyCircle.com and other leading publications. She blogs at Pet News and Views.