Following a Weight Loss Plan for Cats

By Canadian Academy of Veterinary Nutrition (CAVN), Caitlin Grant, DVM, DVSc, Dip ECVCN; Krista Williams, BSc, DVM; Ernest Ward, DVM

Weight loss is tough for anyone - two- or four-legged! However, losing weight and getting in shape can potentially add years to your cat's life, and can also make those extra years more enjoyable. Helping your furry feline to shed a few pounds may be more achievable than you think. It requires a commitment to weight loss and fitness, attention to detail, and partnership with your veterinary healthcare team.

Why should my cat lose weight?

Profile of an overweight cat.As little as two pounds above the ideal body weight can put your cat at risk of developing some serious medical conditions. Unfortunately, when a cat is overweight or obese, there is no question that it will develop a condition secondary to the excess weight, just how soon and how serious. Some of the common disorders associated with excess weight include:

  • type 2 diabetes (an obese cat is three times more likely to develop this serious disease than a cat of normal weight)
  • heart disease
  • osteoarthritis (arthritis)
  • increased frequency of joint injuries
  • high blood pressure
  • some forms of cancer - especially intra-abdominal cancers

Overweight and obese cats usually have shorter lives than their fitter, normal weight counterparts. Heavy cats tend to physically interact less with their families and are less energetic and playful. They tend to lie around more, so it is easier to overlook early signs of illness, since we may attribute their lethargy to their normal laziness.

"Many cats also experience muscle loss secondary to inactivity, which can make it even more challenging for them to move around."

Many cats also experience muscle loss secondary to inactivity, which can make it even more challenging for them to move around. For some cats, this muscle loss could manifest as inappropriate house soiling – because they don’t have the strength or energy to get to the litter box. They may also have a poor hair coat if their weight impacts their ability to groom themselves.

How should I begin a weight-loss program for my cat?

Profile of a cat at its ideal weight.Theoretically, weight loss seems simple enough: fewer calories in, plus more calories out, equals weight loss.

Unfortunately, it is not as simple as that. You should never put an obese cat on a diet without veterinary supervision, as too rapid weight loss, or weight loss with inappropriate food, can be quite dangerous.

Your veterinarian will perform a physical examination of your cat and will likely recommend some diagnostic testing to ensure that there are no underlying diseases or obstacles that would impact weight loss for your cat.

What makes veterinary weight-loss foods special?

There are several options for veterinary therapeutic weight-loss foods for your cat, including dry, wet, and different flavors. These weight-loss foods have been formulated for calorie restriction. They each differ slightly, and some are meant to be used concurrently with other conditions (e.g., prevention of bladder stones). In general, the key features are:

  • Lower energy density: Weight-loss diets typically have fewer calories per cup or per 100 grams so that your pet can still have a decent volume of food but receive fewer calories.
  • Higher in protein: Preserves lean muscle and still meets protein requirements when the cat is fed fewer calories.
  • Higher in fiber: Adds bulk to the diet, which helps with satiety.
  • Lower in fat: To reduce energy density
  • Higher concentration of vitamins and minerals: Your cat’s intake of essential nutrients is correlated with the amount of those nutrients in the food and how much your dog eats. Purpose-formulated veterinary therapeutic weight-loss foods have a higher concentration of nutrients, so your cat will still meet their requirements, even when fed a reduced number of calories.

Another type of weight-loss food has been formulated with specific nutrients that promote an increased metabolism, which helps cats burn calories more quickly.

Your veterinarian can advise on the best weight-loss food for your cat’s particular situation. If the first approach is not successful, a different weight-loss food should be tried.

What about the over-the-counter (OTC) weight-loss foods – can I try one of those first?

There is actually no OTC weight-loss food for cats (or dogs). Foods in pet stores or other retailers that have a weight claim on the label are still considered adult maintenance diets and should not be fed in a calorie restricted manner; doing so could lead to nutrient deficiencies.

How much should I feed my cat to promote weight loss?

Your veterinary care team will calculate the number of calories your cat needs to lose weight. There are several different equations, and it is important to remember that these calculations are for the average cat. Your cat may need fewer, or more, calories to lose weight. It is essential to follow up with your veterinary team once you’ve started your cat on a weight-loss plan to ensure the number of calories is correct. Often, the initial number is just a starting point, and will need to be adjusted over time.

Your veterinarian may have you first complete a food diary. This is a written log of everything that goes into your cat’s mouth for several days. Your veterinarian can then determine your cat’s current calorie intake and start the weight loss plan at a lower amount.

"Your veterinary care team will calculate the number of calories your cat needs to lose weight."

The food dose (amount to feed each day) depends on the weight-loss food that has been prescribed, as they each have a different energy density. This is one reason why you shouldn’t switch between weight-loss foods without having your veterinary team check the math for you first.

Ideally, your veterinarian will give you a food amount in grams per day, as opposed to cups or cans. Using a measuring cup to weigh food is not accurate and makes it very easy to over- or under-feed. Using a kitchen gram scale is the preferred method because it is much more accurate and allows for easier adjustments. For example, adjusting from 55 grams per day to 50 grams per day is easy with a kitchen gram scale, but how accurately you can adjust from ¾ cup to 2/3 cup per day might depend on how many cups of coffee you’ve had!

How quickly should I introduce the new weight-loss food to my cat?

When you introduce a new diet to your cat, you should expect some time for transition. For cats that are picky or who have had GI upset in the past, a slower transition over about three weeks might be recommended. First, offer small amounts of the new food in a separate bowl. If your cat is a finicky eater, it may take two to three weeks for your cat to decide to eat it. Once your cat is eating the new food, consider the suggested transition guide:

  • Step 1: Mix 25% of the new food with 75% of the old food.
  • Step 2: Mix 50% of the new food with 50% of the old food.
  • Step 3: Mix 75% of the new food with 25% of the old food.
  • Step 4: Give 100% of the new food.

Each step is meant to last two to three days, but you can go faster or slower, depending on how well your cat is doing. For cats that have been exposed to a variety of foods and textures, and who have no history of GI upset with new food, a faster transition might be appropriate.

If your cat refuses to eat the new diet, or if you have any concerns during this initial introduction period, do not hesitate to contact the veterinary clinic for advice. They may recommend some strategies to enhance palatability, such as warming the food, adding a flavoring such as FortiFlora® (a probiotic with flavor enhancer), a small amount of salmon or tuna juice, or giving an omega-3 fatty acid supplement. It is important to talk to your veterinary team before doing any of these things, so they can ensure they are safe (if your cat has other medical conditions) and to ensure the weight loss plan considers the calories coming from these items.

Can I still feed treats?

Cat eating food from a bowl and licking its lips.Yes! A weight-loss plan does not mean getting rid of treats, but it does mean you might have to change how treats are fed and what is fed as a treat. The calories coming from treats need to be accounted for in your cat’s weight-loss plan. A typical rule is that 10% of calories can come from treats and 90% should come from the food. So, if your cat needs 200 calories, 20 can come from treats and 180 should come from the food.

Typical cat treats contain between 1 and 3 calories per treat, but some are much more. Be sure to check the label of any treat packages. Or consider asking your veterinary team for a treat option that pairs with the weight-loss food. Your veterinary team can help you design a treat budget, so you know exactly how many of each kind of treat you could give each day without going above the 10% rule.

How can I encourage my cat to get more exercise?

Cats were not designed for long bouts of activity. Wild cats evolved as stalkers who expended very little energy in seeking their prey and seldom strayed far from their territory. When cats come across prey, they burst into an intensely anaerobic and short-duration pursuit. Most wild cats pursue their prey at top speed for less than a minute. Once this activity is complete, they require hours to recover for the next hunt.

When it comes to domestic cats, it can be challenging to promote more exercise, and so we must be creative to get them to expend more energy. Also, each cat is an individual, so what works well for one may not work for the next. You may have to try a few strategies, and give your cat some time to adapt, before you see success. Some ideas include:

  • Move the food bowl upstairs or downstairs, changing its location frequently, so the cat always must walk to get to its food bowl. Cats are smart and if the food bowl moves upstairs, they will move upstairs to find it.
  • Move the food bowl as far away from your cat's favorite haunts as possible. Many overweight cats will sleep and lounge near the food bowl so they do not have to go far to get a snack.
  • Invest in a food puzzle, snuffle mat, or other food dispensing toy that requires your cat to interact with it to get pieces of food. Fill these interactive objects with a specific amount of dry food, and it is up to the cat to work at getting the food out.
  • Try tossing your cat’s kibbles down a long hallway or across the room to make them chase it at mealtimes.
  • Schedule active play times for you and your cat. Use feather toys, laser pointers, paper or foil balls, or anything else that your cat finds interesting to chase. Try to play with your cat for ten minutes, twice a day. You can do this while you eat, watch television, or even read. For many cats, variety is important, and what is exciting today may be boring tomorrow. You can give them one of their meals or a couple of treats from the as a reward at the end of the play session.

See the handout "Exercising Your Cat for Weight Loss" for additional ideas on exercising your cat.

How can I discourage my cat from begging for more food?

Cat eating from an automatic feeder - something that can help reduce begging.It can be challenging to avoid giving in when your cat begs, especially if this occurs in the middle of the night or before your alarm. Remember that new habits take time and rewarding cats for begging will only cause them to beg more. Here are some tips for managing begging behaviors:

  • Use an automatic feeder, so your cat learns to beg the feeder and not you.
  • Use an automatic feeder that allows you to control the amount of food that comes out in a serving, or a smart device that records your cat’s food intake.
  • Sometimes we can misinterpret attention-seeking behavior as food begging. Instead of rewarding with food, give your cat attention with pats, brushing, or by playing with them. 
  • Adjust meal size and frequency. Research is not conclusive: some studies suggest smaller, more frequent meals are better for satiety (fooling cats into thinking they are getting more), whereas other studies suggest fewer, larger meals have a better impact on satiety. One method may work better for your cat (and your schedule). The important thing is to ensure you are consistent with the total amount of food each day.
  • Offer fresh water instead of food. If your cat is eyeing the empty food bowl, a drink of cold, fresh water may satisfy that craving.

I have more than one cat, but only one is overweight. How can I feed them different foods?

Depending on your other cat’s nutritional needs, you might be able to feed them the same food, as many weight-loss foods are also appropriate for maintenance of adult cats. If your second cat does not need to lose weight, you will feed them a larger portion. You could ask your veterinary team for an appropriate food dose.

Even if the same food is fed, it is essential that your cats do not share a dish or steal from each other, as this can add additional calories. Some ideas for how to do this:

  • Feed your cats specific meals during the day and monitor mealtime. Remove any leftover food after the designated mealtime.
  • Feed the cats in separate locations. Feed the overweight cat her diet in one room, while feeding the other cat elsewhere. Allow them to eat for a specific time, generally 15 to 30 minutes, then remove any uneaten food until the next feeding.
  • Feed the normal-weight cat up high, where the overweight cat cannot go.
  • Depending on the size discrepancy between your cats, you can devise different ways to allow the smaller cat access to food where the larger cat cannot fit. You can use a safety chain or hook and eye closure on a door, so the door opens just enough for the thin cat to get in. Alternatively, you can use a large box and cut two small doors in it to allow the smaller cat in to eat.
  • Use a commercial feeding station that opens only when it recognizes your cat’s microchip.
  • Never leave food out while you are away. You cannot control who eats what when you are away.

How often should my cat come in for a recheck or weigh-in?

After you have started a weight loss program for your cat, under your veterinarian’s guidance and instruction, it is critical to determine if the prescribed plan is working. A plan that is working means that your cat is eating the prescribed diet in the prescribed amounts, is not getting any unaccounted calories, is not having any adverse reactions such as vomiting or diarrhea and is losing weight appropriately. Your cat should be reassessed within one week of initiating the diet plan – even if you are still transitioning to the new food at this time.

"Your cat should be reassessed within one week of initiating the diet plan – even if you are still transitioning to the new food at this time."

Once your cat has fully transitioned to the new food, another assessment should be done within one to two weeks so that your veterinary care team can ensure the feeding amounts are appropriate. After that, your cat should be weighed at least every other week until the goal weight is achieved. Your veterinarian might allow you to weigh your cat at home using a luggage scale or baby scale and report those weights. In that case, you should still bring your cat in to the clinic for an assessment once per month to ensure you are getting an accurate measurement on your home scale.

How long will my cat need to be on a diet?

Each cat is an individual and may require adjustments to the recommended diet or routine, which could lengthen the duration of the weight loss plan. Though weight loss is the goal, rapid weight loss is not a good thing, as it can lead to loss of lean muscle and can put your cat at risk of severe liver disease (hepatic lipidosis or fatty liver syndrome). Ideally, cats should lose somewhere between 1% and 2% of their initial body weight per week, and closer to 0.5% might be more appropriate for morbidly obese cats.

The time it takes for your cat to reach their target body weight will depend on a few factors:

  • how quickly they accept the new diet plan;
  • the rate of weight loss (e.g., losing 1% will take twice as many weeks as 2%); and
  • the total amount of weight to lose.

For most cats, the secret ingredient to successful weight loss is a strong partnership between their dedicated, committed, family and the veterinary team.

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