Weight Reduction in Cats – General Information

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Weight loss is tough for anyone – two- or four-legged! However, losing weight and getting in shape can add not only years to you or your pet’s life; it can also make those extra years more enjoyable. Shedding a few pounds off of your furry feline may be easier than you think. It simply requires understanding the need for weight loss and fitness, attention to details and simple assistance from your veterinary healthcare team. 

Why a Healthy Weight is Important for your Cat

As little as two pounds above your cat’s ideal weight can put it at risk for developing some serious medical conditions. Unfortunately, when a cat is overweight or obese it no longer is a question of “if” your cat will develop a condition secondary to the excess weight but “how many and how soon!” Some of the common disorders associated with excess weight include:

  • Type 2 diabetes – a cat with obesity is at least three times more likely to develop than serious disease as a cat of normal weight
  • Kidney disease
  • Chronic inflammation
  • Heart disease
  • Osteoarthritis
  • High blood pressure
  • Many forms of cancer – especially intra-abdominal cancers

Further, overweight felines and cats with obesity are expected to live shorter lives than their fitter, normal weight counterparts. Heavy cats tend to physically interact less with their families and are less energetic and playful. Because they tend to lay around more, it is easy to overlook illnesses since we attribute their lethargy to their “normal laziness.” We are just now learning how serious and threatening a few extra pounds can be for both humans and our cuddly companions.

Start with Calories

For weight loss, the formulas seem simple enough: fewer calories in plus more calories out equals weight loss. Unfortunately, it’s not as simple as that formula makes it appear. For starters, cats that are overweight or obese must eat. Their physiology is different than humans or dogs and if they do not eat for as little as two consecutive days, they can develop a life-threatening form of liver disease known as hepatic lipidosis. Obese humans starting a diet program are also vulnerable to this serious condition. It is for this reason that you should never put your cat on a diet without the assistance of your veterinary healthcare team.

Let’s start by calculating the calories your cat needs. You’ll first need to have your cat examined by your veterinarian and an ideal weight calculated. The average domestic cat should weigh approximately eight to ten pounds. If your cat is 18 pounds, you can calculate its ideal weight to be 10 to 12 pounds. A basic formula for weight loss in cats is:

  • Ideal weight in pounds divided by 2.2 give you weight in kilograms (kg)
  • Calculate the Resting Energy Requirements (RER) based on this ideal weight
  • RER in kcal/day =
    • [70 x (ideal weight in kg)] ^¾ or [70 x (ideal weight in kg)] to the ¾ power or
    • 30(ideal or target body weight in kilograms) + 70
  • For weight loss in cats multiply RER times 0.8

Ideal weight (lbs)

Calories to feed (kcal) at 80% RER per day







Note: This is a general guideline only and is not meant as a substitute from your veterinarian’s specific recommendations.

For many cats, the best way to feed will be by offering a canned diet food fed several times per day. It is vital that you count calories when entering into a weight reduction program. Feeding too much will result in no weight loss and feeding too little can result in serious consequences such as hepatic lipidosis.

The Art of Changing Diet

When you are introducing a new diet to your cat, allow several days for the transition. In general, we recommend gradually adding the new diet over a one to two week period. Start by substituting one-quarter of the diet for two to three days, then increase to one-half total volume of food for another two to four days, then three-quarter new food for a final three to five days before completely switching to the new diet.

To enhance the palatability of the diet food, try warming the food, adding ketchup, oregano or garlic and even adding an omega-3 fatty acid supplement or salmon juice over the food. One of the reasons canned diet foods work better is due to the fact that our finicky felines often prefer wet food over dry.

Creative Exercise

In an ideal world, we’d take a jog with our cats or enjoy a mile swim in the morning to stay fit. We certainly don’t live in that world! Getting our cats to engage in aerobic activity isn’t just difficult – it goes against their very nature. Cats weren’t designed to function as scavengers and persistence hunters the way humans and dogs evolved. Instead, cats evolved as stalkers who expended very little energy in seeking their prey and seldom strayed far from their territory. When they came across prey, they burst into an intensely anaerobic and short-duration hunt. Most wild cats would pursue their prey at top speed for less than a minute. Once this activity was complete, they required hours to recover for the next hunt. If they missed several prey opportunities in a row, they could be in serious danger of lacking the energy necessary to successfully hunt.

Our domestic cats are simply smaller versions of these wild felines. While we may take our dogs out for a brisk walk or jog, our cats aren’t designed to perform that sort of activity well. Our cats prefer the hundred-yard dash to the marathon. Even more complicating is the fact that our cats evolved on a diet based on protein as opposed to humans and dogs that can eat vegetables, proteins, fats, you name it. Since cats are obligate carnivores, the same dietary rules don’t apply. Many cats will do better on a high protein, low carbohydrate diet for weight loss for this reason.

Just because cats aren’t good endurance athletes doesn’t mean we shouldn’t encourage them to move. Some simple tips for getting your cat to move more are:

·      Play “Find the Food” Move the food bowl upstairs or downstairs and rotate it so that the cat always has to walk to get to its food bowl.  Cats are smart, and if the food bowl moves upstairs, they’ll start relocating upstairs, too.

·      Move the food bowl as far away from your cat’s favorite haunts as possible. Again, many cats will sleep and lay near the food bowl so they don’t have to go far when the eatin’ urge hits!

·      Use feather toys, flashlights, paper bags or balls, anything that your cat finds interesting to chase. Try to engage your cat for ten minutes twice a day. You can do this while you eat, watch television or even read. There are numerous toys that move and squeak that may also be interesting to your cat. Experiment and understand that what is exciting today may be boring tomorrow.

Rechecks and Weigh-Ins

After you’ve put your cat on a weight loss program, it’s critical that you determine if it’s working for your cat. Each cat is an individual and may require many changes in diet or routine before finding the correct approach. In general, your cat should be weighed every month until the ideal weight is achieved. If there is no significant weight loss in one month, typically about one pound, then a new approach should be pursued. There is nothing more frustrating than persisting in a behavior pattern that is not achieving the results we desire when a slight change could deliver significant improvements. Work closely and actively with your veterinary healthcare team to reach your goals faster and more safely.

Reluctant Patients

What about the cat that wakes you at four in the morning to be fed or the cat that meows incessantly or head bumps you until you feed them? Our cats have often trained us well and know exactly which buttons to press when it comes to getting their way. Here are some tips for handling a pesky kitty:

·      Do not use a self-feeder. While this seems obvious, auto-feeders are nothing more than unlimited candy machines to a cat.

·      Pet your cat or play with it when it begs for food. Many cats substitute food for affection so flip the equation and you may find that playtime displaces chowtime.

·      Feed small meals frequently – especially give a last feeding for those cats that like to wake you up in the wee hours begging for more goodies – divide the total volume or calories into four to six smaller meals – whatever you do, don’t feed extra food

·      When the bowl is empty and your cat is pleading, add a few kibbles to the bowl. By a few, try ten or fifteen – not a handful.

·      Offer fresh water instead of food. Many cats love fresh water so when they are eyeing the empty food bowl, fill up the water bowl instead.

Multi-Cat Households

What do you do if one cat is normal weight and the other is diagnosed with obesity? While there are countless creative solutions to this problem, here are a few we’ve found successful”

·      Feed separately – this is the ideal solution for multi-cat households. Feed the cat diagnosed with obesity its diet in one room while feeding the other cat its food elsewhere. After a prescribed time, generally 15 to 30 minutes, pick the food up until the next feeding.  

·      Feed the normal weight cat on an elevated surface where the cat with obesity can’t go.

·      Do not leave food out while you’re away. In this scenario, you can’t be sure who ate what and the smart money is on the cat with obesity. 

Most cats will achieve their ideal weight within six to eight months. If the process is taking longer than this, something needs to be changed.

Typical minimum weight loss per month for a healthy adult act is 0.5-lbs. Ideally, your cat will lose close to one pound per month. Some cats may need to go slower while others may shed the pounds more quickly.

If you're not seeing desired weight loss within 90 days, change daily calories, pet food brand, increase protein, change formulations -- change something!

Be sure all potential underlying medical causes for obesity have been addressed before beginning any weight loss program. 

Always remember the reason for your hard effort is to help your cat live a longer, healthier life. For most cats, the secret to weight loss is a dedicated, committed and concerned family member. Our cats don’t understand that their excess weight is killing them. It’s up to us as good stewards to protect them from harm and not inadvertently contribute to their premature death or development of debilitating diseases. Together – veterinary healthcare team, you and your cat – we can help your cat achieve its weight loss and fitness goals safely and successfully. 


Today’s Weight: ___________ lbs.                     Target or Ideal Weight: __________ lbs.


My cat’s daily caloric requirements for weight loss: 0.8 x [30(weight in lbs / 2.2) +70] = 


____________ kcal per day or _________________________ cups / can(s) per day


Recommended Diet:




Amount of recommended diet to feed per day:




Next weight check: _________________________________