How to Help Your Pet Lose Weight

dog being examined by vet


Trimming the Fat: Six Steps to a Perfect Score

Pet obesity is our focus this month and if you haven’t yet read our first blog on the subject (Keeping Score – How Fat is Too Fat?), here’s the lean version: 1 Fat dog and catMore than half of cats and dogs in North America are overweight or obese. (Ask any vet at Royal York Animal Hospital and they’ll tell you that statistic sounds about right based on our own experience.) By overweight, we mean 10-19% above optimal weight. And by obese, we mean 20% or more above optimal. How do we know whether a pet is too fat? By performing a body condition score (BCS). Why do we care? Because excess fat is damaging on so many levels, and it compromises a pet’s quality of life and shortens his/her lifespan by up to 2.5 years.

Now here’s the skinny on what has to happen in order to win the battle of the bulge. First, it’s important to understand that there’s no one-size-fits-all approach to weight loss. But there are six basic steps you can follow to get a perfect body condition score – and maintain it. (Note: There’s a lot to digest here, and you may not want to do it all in one sitting. Feel free to take breaks, walk your dog or play with your cat and get a jump on step 5!)



I’ll use the Golden Retriever pictured here to illustrate how we get this done. Jessie was about 5 years old when I first met her 4 years ago, and she’d already succumbed to the creeping “middle-age spread” that so many pets experience by mid-life. Weighing in at 101.5 pounds, she’d taken on the proportions of a coffee table (she’d long since lost any semblance of a waist and from an aerial view, her body looked flat and rectangular). Her ideal body weight is about 70 pounds, so she was 45% overweight with a BCS of 5/5 (read: obese) when I first laid eyes on her. Time for an intervention.

1. Recognize the problem and commit to correcting it.

Many pet owners are surprised to learn that their pet is overweight. Some are even a little offended when it’s pointed out. (“Who you callin’ fat?”) But we’d be doing our patients a disservice if we didn’t call it like we see it – and we see hundreds of pets in a month and thousands in a year, so we get a lot of practise evaluating and comparing pets’ body condition scores. (See Keeping Score: How Fat is Too Fat?) The consequences of weight gain going unchecked are too serious to ignore. (See The Fallout of Fat: What’s the Big Deal?) But we can’t do anything to help a pet slim down until his/her owner agrees that that pet needs to lose weight and commits to making it happen. For significantly overweight or obese pets, that means committing to the full meal deal – a formal weight loss program like the one described here, starting with some blood work and a urinalysis to rule out underlying issues (such as hypothyroidism, diabetes, and kidney or liver disease) that’ll interfere with our progress or dictate which diet food we recommend. 3 cartoon (See Doc he's not fat)

Jessie’s Story:

Jessie’s owner knew Jessie was overweight and had tried to work on it over the years. (Not easy with a dog that’s as food driven as Jessie. You know the type: A “Hoover” that sucks up every last crumb and then looks for more and that seems to put on a pound just by looking at a kibble.) You can see from her weight chart below that she’d been obese for a few years and that she had a pattern of losing some weight, then regaining it (and then some). What Jessie (and I) needed from her owner was a renewed commitment to try again – this time, with a formal program that would involve a therapeutic weight loss diet and the necessary exercise and follow-up (weigh-ins and calorie adjustments). “I’m in,” came an email from Jessie’s owner a few days after we chatted about the problem and how we could solve it if we worked together.

4 Jessie weight graph 1

2. Choose an appropriate food.

When a pet owner recognizes that a pet needs to lose weight, the temptation might be to just cut back on the food currently being fed to that pet (typically some kind of maintenance diet) or to choose a commercial weight loss or weight control diet available over the counter (i.e., from a pet store). That can certainly work if a pet is just mildly over weight. (See “Note” below.)5 dog with celery But when we’re talking about the need for significant weight loss, that pet needs to be on a therapeutic (read: prescription) diet designed (and tested) for that purpose. (That’s assuming you’re not willing to work with a board-certified veterinary nutritionist to design a home-cooked weight loss diet for your pet, which is another option.) So why is that? The amount you’d have to cut back on a maintenance diet in order to restrict enough calories to effect significant weight loss will result in two problems:

  • your pet will be robbed of essential nutrients (protein, minerals, vitamins) he/she needs to stay healthy
  • your pet will no longer feel satisfied and will start to beg and forage for food (how long will it take for you to cave if you’re met with begging from a little beggar as cute as this?)

Meanwhile, where commercial diet pet foods are concerned, there are no clear nutritional and caloric standards that companies have to follow when making label claims such as “less active,” “healthy weight,” “lite,” “weight control” and so on. As a result, there’s a lot of variation in these diets’ caloric content and the proportion of nutrients, fibre and digestibility in each one. It takes some knowledge of nutrition and product labels (for example, what constitutes “crude fibre” and “guaranteed analysis”) and careful evaluation to understand what you’re getting and whether or not it’s a good bet for your pet. 6 Metabolic treats

Therapeutic weight loss diets have two important features not found in other diets:


  • Lower Energy Density – the name of the game for achieving weight loss in cats and dogs is to reduce the caloric density of their food. That’s done by lowering fat and increasing fiber and moisture (and sometimes even adding air). But that’s not all there is to it…
  • Fortified Nutrients – if you restrict calories enough to effect significant weight loss, the body will eventually turn to muscle for energy. Well that’s no good. The idea is to lose fat, not muscle. So therapeutic diets include higher levels of protein to prevent muscle loss. They also include higher amounts of vitamins and minerals so that none of the nutrients a cat or dog need are sacrificed while losing weight. Some of these diets also include L-carnitine to help with fat metabolism.

Hill’s has augmented that strategy further with a diet called Metabolic that makes use of a growing field in nutrition called nutrigenomics. It basically boosts a pet’s metabolic rate to help with weight loss. It’s not the Holy Grail of weight loss diets (no such diet exists), but it is one of the ones we prescribe when it’s appropriate to do so. This particular diet comes with cute prescription treats to satisfy the treat-giver in you. If your pet needs to be on a therapeutic diet, your veterinarian will work with you to choose an appropriate one (canned or dry or a combination of the two depending on cost and preference). Note: If your pet has just a little weight to lose and you’re going the commercial diet route, have a read of the World Small Animal Veterinary Association (WSAVA) guidelines for Selecting Pet Foods before you head out to the store.

Jessie’s Story: Jessie needed to lose at least 25 to 30 pounds. (The human parallel would be a woman who needs to lose about 45 pounds.) The only way I could make that happen safely (and without taking a long time to do it) was to use a therapeutic weight loss diet. I prescribed Royal Canin’s Satiety Support.

3. Figure out how much to feed.

7 Eating HomeworkTo lose fat, we need to feed fewer calories than a pet is currently getting. But how many fewer? It’s really important that a pet (especially a cat) doesn’t lose too much too fast (see step 6), so we start with one of two approaches and make adjustments along the way:

1. If we can figure out exactly how many calories a pet is currently getting (from meals, treats, food used to give medicine, and so on), then one approach is to drop his/her caloric intake by about 20 to 30%. Sounds simple enough. But the trick here is getting an accurate account of a pet’s intake. It can be a challenge, for example, to determine the number of calories in the treats you’re buying from pet stores or the extra calories your family, friends and neighbours may be feeding your pet.

2. If we can’t get an accurate diet history, then we estimate a pet’s ideal body weight, calculate its resting energy requirement (RER) and feed a percentage of that (80% and 100% of the RER is considered a good starting point in cats and dogs, respectively). If we’re going to do this by the numbers (i.e., get this right), here’s the formula we need to use:

Note: Any smartphone’s calculator will have the power function needed to do this calculation. 9 How cat sees math problemsWell that’s a bit mind numbing even for us v eterinarians. Happily, the diets we prescribe come with tools that take care of the math for us. But again, this is just a starting point. Every pet’s metabolism is different, and we’ll need to do some tinkering with calorie counts along the way. Once we know how many kcals a pet needs in order to lose weight, we need to figure out how many cups (or grams) of kibble (or cans of food) to feed. You’ll find the number of kcals/cup (and so on) on the product packaging. The most accurate way to measure food is to weigh it on a digital gram scale. But if you’re not prepared to invest in a scale and your pet is on a Hill’s weight loss diet, you’ll need a Hill’s measuring cup to measure kibble (we’ll give you one). Why does that matter? Because there’s nothing “standard” about standard kitchen measuring cups, and using anything but the measuring cup that a Hill’s diet was designed for introduces inaccuracies in measurements. Ditto for Royal Canin weight loss diets.

10 Hills measuring cupJessie’s Story: Jessie’s ideal body weight is about 70 lbs or 31.8 kgs (divide lbs by 2.2 to get kgs). So she needed 1.0 x (70 x 31.8/0.75) = 937.4 kcal per day to lose weight. And Satiety Support has 231 kcal in a cup, so she needed about 4 cups per day of that particular diet to start. I had a Royal Canin software program do most of the heavy lifting (read: calculating) for me with each weigh in. And if something didn’t make sense or wasn’t quite working out along the way, I consulted one of Royal Canin’s veterinary nutritionists. (Another benefit of going on a prescription diet is that your vet has access to specialists in veterinary nutrition.)

4. Choose a feeding method.

Portion control is an important part of a weight-loss program. It’s best to feed multiple small meals a day for two reasons:

  • The process of digesting and absorbing food expends some energy, so multiple feedings is another way to help burn calories.
  • Spreading calories out over the day also manages hunger better and reduces begging behaviour.

11 Slimcat food dispenserMost people can manage feeding two meals a day. If you can feed three or more meals a day, even better. Using an automated dispenser, food-dispensing toys, or specialized food bowls can help as well. The latter options provide some mental stimulation, slow down feeding (and help a pet feel more satisfied after a meal), and for cats, stimulates and satisfies their inner hunter. Check out the SlimCat video to see cats using one brand of feeding ball. (We carry this one at our clinic.) Our Hospital Manager, Helen, feeds her dog, Indy, with both a specialized food bowl and a tricky treat ball:

What about treats? Being on a diet doesn’t mean that your pet can’t have any. But the treats he/she does eat have to be within the caloric restrictions established for his/her weight loss program – and should be less than 10% of the calories calculated. If you feel the need to give your pet treats, the easiest thing to do is hold back a few of his/her allotted kibbles for the day and use those as treats.

Jessie’s Story: Jessie was fed two meals a day. Any treats she got came from her daily allotment of kibble. No Benny Bullies from our staff when she came in for her weigh-ins – just lots of praise and attention. And Jessie’s family members were asked to get on board and leave all feeding to Mom. (If there was any cheating on this diet, it wasn’t apparent to me based on Jessie’s progress.)

5. Exercise your pet

Expending some energy is also an important part of any weight-loss plan. Any extra calories a body doesn’t need to run things will be converted to fat unless they’re burned off with some exercise. But go easy, especially if your pet has an underlying medical issue like heart disease or arthritis. No weekend warriors please. Slow and steady wins this race. 12 cat on leashThe idea is to start with an amount your pet can comfortably tolerate at first (even if it’s just to the front yard and back). Increase exercise by a small amount each day, and work up to about a 20-minute walk if your pet couldn’t manage that from the outset. Note: If your pet has had surgery of any kind, check with your surgeon about when and how much exercise is safe. Swimming is a great form of exercise for dogs that like the water; it burns more calories than walking.

Okay, that’s not going to work in winter, but keep it in mind for later in the year. Once your dog is able to tolerate more activity, you can always sign up for things like agility classes or the new Scent Detection sport for dogs. And if you like gadgets and need incentive to keep your dog active, you can outfit him/her with a FitBark monitor that tracks his/her daily activity (and earn BarkPoints while you’re at it). Whatever works for you. (For vet tech, Kim, that’s swimming, agility, fetch, and good old fashioned “tug of war” with her brood.) 13 Swimmer Cats are a bit more of a challenge, but if you think like a hunter and use a little creativity, there are games you can play and perches you can set up that can help your cat burn some energy. All cartoon kidding aside, there are people who’ve been successful leash-walking their cats. How cool is that? Hill’s lists some ideas for exercising both cats and dogs here.

The American Association of Feline Practitioners has some more in their Behaviour Guidelines (pgs. 27, 40). Ask our technicians for ideas too. They’ve got plenty of good ones.

14 Agility Class 15 Fetch 16 Tug o War

Jessie’s Story: Jessie worked up to (emphasis on “worked up to”) a couple of one-hour walks a day and lots of romping at the cottage. As the weight started to come off, her owner noticed how much more energy Jessie had and how much easier it was for her to climb into the family car.

6. Do the necessary follow-up.

This is where diets tend to fail. Without checking your pet’s weight on a regular basis and checking in with your veterinary team for calorie adjustments, trouble-shooting tips, and pep talks, what invariably happens is that your pet doesn’t lose much weight. So you get discouraged and decide to ditch the therapeutic diet because you think it isn’t working (and why spend the money on something that’s not working?). And eventually we’re right back to where we started (or worse). Once your pet starts a diet, it’s important that you weigh him/her every 2-3 weeks so we can monitor progress. (Once we’ve got a healthy pattern established, we can move to monthly weigh-ins.) We need to make sure that your pet is actually shedding some weight but not shedding it too quickly. (See insert below.) Too much or too little progress will call for a calorie adjustment. (Remember step 3? We’ll do the math for you.)

Swing by and use our scale any time (no appointment necessary). And be sure to ask our staff to record your pet’s weight in his/her record. If you’re none too keen to bring your cat in to the clinic just for a weigh-in, then by all means, do it at home if you have a scale. (Weigh your cat’s carrier, then weigh your cat in the carrier and subtract the two. Then call and ask us to record your cat’s weight.) Numbers don’t lie, and if we’ve got them, we can chart your pet’s progress and print a copy for you to pin up at home so the whole family can see how your pet is doing. Keep in mind that it can take months to reach the target weight we’ve set for your pet. But it is reachable if you make the commitment and do the necessary follow-up. The beauty is that our clinic provides a built-in support group to help you get there. Think of us as a kind of life coach or personal trainer (but not the unforgiving “boot camp” kind!) for your pet’s weight loss program.18 cat  dog scale Jessie’s Story: You’ll see from Jessie’s weight chart below that with diet and exercise and regular weigh-ins, she lost weight nice and gradually. (It was a thrill to see those numbers come down.) It took Jessie 6 months to reach her ideal body weight. And once she did, we transitioned her to a maintenance diet.

19 Jessie wt loss  curve

You’re thinking: “Yes, but did she keep the weight off?” Well, let’s be realistic. We are talking about a highly food-driven Golden Retriever (a breed whose metabolism tends to run a little slower than other breeds). Her weight went up just a bit, then down, then up a bit more than either Jessie’s Mom or I could live with. So what happened?? Life. A knee injury that prevented Mom from exercising Jessie. Kids that were overly generous with treats over the Christmas holidays. An obese-prone dog.

No biggie, though. We won the battle of the bulge once. We knew we could do it again. (And this time we didn’t have nearly as far to go.) We put Jessie back on a formal weight loss program that involved feeding her a prescription weight loss diet, feeding her from a Slo-bowl feeder (pictured here) designed to make her take her time so she feels more satisfied after a meal, and making sure she got regular exercise. And once she achieved pretty close to her ideal weight, we transitioned her onto a maintenance diet that would help keep her weight in check. She’s been on that maintenance diet for a number of months now. At her annual exam about a month ago, I was pleased to see she was holding steady at 70.8 pounds (pretty much her ideal weight). Good dog!

20 Jessies slo bowl Take home message: Once you get the weight off, you need to work at keeping it off. For some pets that’ll be a bigger challenge than for others. But you have a team of really great people in your court to help you with that.

Okay, that’s it. That’s all I’ve got. If you’ve hung on this far, you deserve a treat. I recommend something delicious and satisfying (calories be damned just this once).

Dr. Iz Jakubowski