Blog post by Dr. Vicky Simon BVetMed MRCVS
Obesity is a growing problem amongst both our human and pet populations. It is the most common nutritional disorder in pets, and it is believed that over 30-50% of the pet population in the UK is overweight. In fact, last year the PDSA released a statement saying that fat cats, dogs and rabbits are likely to outnumber healthy ones within 5 years – what an appalling prospect!
Pets are considered overweight when they’re carrying 10-15% more than their ideal body weight, and obese when carrying 20-25% over their ideal. Obesity is defined as an excess of body fat, to a degree where it impairs health, welfare and quality of life.
It is generally caused by feeding too much, and/or not exercising enough. I was horrified to read that in the 2014 PDSA Animal Welfare report they estimated that in the UK a quarter of a million dogs don’t get walked at all! (They also found that 6 million dogs go for a daily walk shorter than an hour long.) There are a few genuine medical reasons for obesity, which I’ll go into later.
Adipose tissue (fat) is not just an inert bit of extra baggage for your pet to carry, it secretes hormones affecting appetite, inflammation, insulin sensitivity and bodily functions. As adult humans, our weight is our responsibility, but for the majority of pets, their weight is determined by you, their owner. We’ve all stuck our hand in the cookie jar when we know we shouldn’t, but our pets don’t have access to this glowing jar of delights - they depend on us. So if your pet is overweight, it’s up to you to step up and take on the responsibility for helping them return to their ideal weight.
There are certain things that can predispose dogs to becoming overweight. Certain breeds have been found to be more likely to become obese, compared to others, and risk of obesity increases with age. Female dogs are more likely to become obese than male dogs, and neutered dogs of either sex are prone to gaining weight. This can be explained by the fact that Oestrogen (found in higher levels in females than males) slows down fat production, so if owners fail to decrease their pets’ rations post-neutering, the drop in Oestrogen that occurs will mean that they will produce more fat. Studies have also found that overweight humans are more likely to have overweight pets, thought to be due to a combination of exercising less, and being less able to recognise obesity. Some other risk factors for a pet gaining weight include any periods of rest – for example when they injure themselves, after surgery, if their owner has injured themselves, or when they go into the kennels & maybe don’t get walked as much as when they’re at home. A lot of owners wouldn’t even think to decrease their pets’ rations during these periods, as it seems so unrelated to the problem, but this could be the start of a downhill slide into obesity. The final risk factor is diet, but we’ll talk more about that later – Can you guess what I’m going to recommend?!
As mentioned earlier, there are various medical reasons for excessive weight gain in pets, so if your pet is failing to lose weight, despite your best efforts, then do get them checked out by your vet. As well as neutering, other hormonal disturbances can lead to obesity. Hypothyroidism, low levels of thyroid hormones, is becoming more commonly recognised, and any patient we see that is failing to lose weight has their thyroid levels tested. Thyroid hormones are involved in metabolism and energy expenditure, so low levels can slow your dogs’ metabolism, and make them more lethargic, amongst other things. Hyperadrenocorticism (Cushing’s disease) is an overproduction of stress hormones, and can also lead to weight gain. This is for similar reasons as the weight gain seen with long term treatment with steroids. The stress hormones are the body’s natural steroids, and steroids lead to an increased appetite. Anticonvulsant drugs can also have this side effect. Finally there are certain types of tumours which can produce hormones, leading to an inappropriate imbalance in these, which could lead to obesity as a secondary effect.
Now, when it comes to fat dogs, I’m afraid I’m not one to sugar coat anything (that would only make it worse right?!) In fact I’ve been told I’m brutally honest and it can be a harsh truth to take for some owners! I’ve heard all the excuses: “Oh he’s just big boned”, “Oh no, this is what her mother was like”, “He’s in show condition”, “She would get cold if she was any thinner”, “He’s got a slow metabolism” – you can say what you like, but if your dog is fat, It Is Fat. And I will tell you so! Some owners will argue with everything they have to get me to retract my comments on their pets’ weight, but it won’t change the facts, and it can get terribly tiresome! Some owners even find it extremely amusing that they have a fat pet, and if this continues, despite discussion about weight loss, I’m afraid they get told “You are killing your pet with kindness” (There was even an article in our Vet Times about this). And that is the sad truth about excessive weight...
Before we talk about the health risks associated with obesity, let’s look at how it affects welfare directly. Some overweight pets become so large that they struggle to get up and down or move around at all. Even a small amount of excess weight can mean your dog cannot run around and explore as they would like to. What many owners fail to see, as they trickle-feed treats into their pets’ expectant begging faces, is that this is in fact a lapse in welfare – they are mistreating their pets in the very act of ‘treating’ them. One of the 5 freedoms of animal welfare is ‘Freedom to express normal behaviour’ – How many overweight pets can truly express normal dog behaviour?
So now to the serious stuff: the major health risks that adversely affect your pets’ health, and so the length of their life (Obesity alone can decrease dogs’ life expectancy by 2.5 years, with diet restriction having the opposite effect & increasing longevity!):
Cardiovascular disease – obesity has been linked with high blood pressure and all of the secondary effects that come with this. The heart itself is also put under much greater strain and overweight dogs can suffer from various heart conditions. Primarily if you consider the poor little heart trying to force the blood through all those fat-surrounded vessels – it’s bound to struggle!
Respiratory disease – excess fat on the outside of the ribcage can restrict its ability to expand and contract, which coupled with excessive abdominal fat pressing up on the diaphragm, can hugely limit a dogs ability to expand its lungs and breathe. This obviously isn’t ideal anyway, but it can also predispose your dog to suffering from heat stroke and exercise intolerance. Overweight dogs also have a greater risk of suffering from tracheal collapse and laryngeal paralysis. An excess of fat can exacerbate symptoms of Brachycephalic Obstructive Airway Syndrome in affected breeds too.
Joint disease – around 25% of overweight dogs have been found to suffer serious joint disorders, both traumatic and degenerative. They are more likely to suffer from osteoarthritis, intervertebral disc disease and cranial cruciate ligament rupture, due to excess weight putting greater strain on the joints and their surrounding structures. Excess weight can also exacerbate symptoms of hip and elbow dysplasia. Once a dog suffers from a joint problem, this often requires restricted exercise, which makes the dog fatter, which makes the joint problem worse, requiring less exercise, making them fatter...do I need to go on?!
Urogenital issues – with increasing fat, pathological changes can occur in the kidneys leading to renal insufficiency. Urinary incontinence is a well known problem for obese dogs, especially those suffering from urinary sphincter mechanism incompetence (USMI) – sometimes these cases can regain continence solely by losing weight. There is one type of urinary crystal that excess fat can predispose too as well. Overweight bitches commonly suffer from dystocia (difficulties giving birth), often requiring assistance or even a C-section.
Liver disease – excess fat is deposited in the liver, which if severe can lead to hepatic lipidosis, or if milder simply to a decrease in liver function.
Digestive issues – overweight dogs are prone to constipation, and can suffer from terrible flatulence (What better reason for weight loss could there be?! No-one wants to have to evacuate the room their dog is in! Although I remember doing this with my grandparents’ dog when I was a child)
Anaesthetic and surgical risks – anaesthesia is much riskier in overweight pets as it is harder to accurately calculate dose rates according to muscle mass, but also because many of the anaesthetic drugs are quickly stored in the fatty tissue, and then when their circulating levels decrease, more is released from the fat, increasing levels again and so extending the anaesthetic unnecessarily and slowing wake up times. All surgical procedures are much riskier in obese dogs because fat is extremely vascular, so they bleed more. Sometimes there is over an inch of fat between the skin and the muscle, which if it oozes throughout the op can make visualisation a nightmare (think of the poor vet here!). In addition, even routine procedures like neutering can be more risky, especially in bitches as the ovarian stumps (or any tied off blood vessel) can ooze incessantly, and be hard to tie off tightly when your hands are all greasy from handling fat! (An overweight bitch spay is in fact my worst nightmare – these have been some of the absolute worst ops I have had to do, sometimes needing a drip because of blood loss, or taking forever as every single vessel in a stretch of fat needs tying off and the general oozing obscures everything!)
Cancer – obese dogs have an increased risk of developing transitional cell carcinoma (a bladder tumour), mammary cancers and lipomas (being fatty lumps, we find that the more fat the dog, the more lipomas they seem to have!)
Diabetes Mellitus – obesity leads to an increase in demand, and so production, of insulin by the body. This is not ideal, but manageable until the point where demand exceeds supply, the pancreas begins to burn out and diabetes develops. This can lead to secondary pancreatitis. Overweight dogs can also suffer from insulin resistance, where the cells simply don’t respond adequately to the insulin present.
Skin disease – overweight dogs struggle to groom themselves properly, leading to excessive scurf, matted fur, a greasy coat and sometimes skin infections, especially if their fat has formed folds where air cannot circulate. This can be severe around the vulva when they are both fat and incontinent.
Reduced immune function – the reason for this is unknown but obese dogs are more prone to infections. As little as a 10% weight loss can have an immune enhancing effect.
There are a few others, but those above are the most important in my eyes (plus I don’t want to take up all of your day reading about fat dogs!)
For me, a key habit that many owners slip into is feeding a set amount, and sticking to this religiously. To me, the amount you feed your pet is a dynamic equilibrium. Yes, there is a rough amount that your pet should eat every day, but you should be assessing them on a weekly basis to see if they should be receiving more or less food. It is easy enough to assess your dogs’ body condition, using a combination of how they look and how they feel. At an ideal body weight they should have a visible waist, both from the top and the side (tucked in and up), and you should be able to feel their ribs and spine, without excessive fat coverage, but not see them (in sight hounds and their crosses you can see their last 1-3 ribs when they are in their ideal body weight – this is a normal breed/body-type variation). We use a couple of scoring systems, either out of 9 or out of 5, and here is a link to an example chart for you to look at from the World Small Animal Veterinary Association (WSAVA):
Of my raw fed patients, I can only think of a handful that are overweight, and those are mostly recent transition pets that are in the process of losing weight. The great thing about raw fed dogs is that they are naturally leaner. In fact, obesity is such a problem that I often get owners coming to me saying “Someone in the park said my dog was too thin” – I assess them and frequently my conclusion is “Their dog is probably too fat” – another sad truth of the growing obesity issue in this country: It is so common that a lot of people have no idea what is normal anymore!
Exercising your pet is crucial for weight loss & maintenance of a healthy weight (as well as for your pets’ general welfare). If they are very large and struggle to walk for too long, don’t let this hold you back! Instead of one or two long walks daily, see if you can go for 3-4 shorter walks, even if they start at 10 minutes long. Remember every little helps! Varying where you walk your dog can encourage more exploration as there are more scents to follow so they are more likely to roam about. Swimming can be great for overweight dogs too, as their weight is held by the water so there is less pressure on their joints – this is particularly good if they have joint issues. It is best for dogs to swim for 5 minutes at a time, then rest, then swim again. Otherwise it is just consistency – regular exercise, every day, with off lead running if possible.
When it comes to diet, it isn’t just the amount fed that affects weight gain. Palatability, meal frequency, protein/fat/carb ratios, quality of food and treat quality & quantity also play a role. In my opinion the absolute best food you can feed your pet for both weight loss, and maintaining a perfect body weight, is Raw (what a surprise!) It is low in carbs and free from grains, which turn directly into sugar in the body leading to fat deposition, and high in protein and fat. It is what dogs are designed to eat, and once they are settled on to it, it is easy to digest. Being high in protein is key when trying to get your dog to lose weight, as low protein diets can lead to loss of lean muscle mass, leading to muscle wastage & weakness . A balanced raw diet naturally contains everything your dog could need nutritionally, and in an easily absorbable natural form. This means they won’t seek out other food (or other dogs’ poo!) because of a deficiency (we see this sometimes with dogs on poor quality diets). It is also a tactile diet – as dogs chew bones or chunks of meat endorphins are released into their system making them happy. It also keeps them occupied for longer so they are more likely to realise they’re full.
Apart from feeding once daily there are a few other things that can help with weight loss if you’re struggling. Personally I think feeding once a day is best as then the dog feels full, rather than constantly half full, seeking a little more. People new to raw, or old hands, trying to get weight off their dog, often notice how little food it looks like they are giving their dogs. It is less and can leave your dog feeling a little empty – so here’s a top tip: add some Psyllium Husk Fibre to the food. This expands once in the stomach, leaving your pet feeling fuller, and also acts as a prebiotic, feeding the good bacteria in the large intestine – win win! On the matter of probiotics, these can also help your dog with weight loss – healthy gut, means healthy digestion – so get some naturally probiotic-rich foods into your dog (think Sauerkraut, Kimchi, Kefir, Live yoghurt etc. [goat or sheep dairy is always better than cow!]) The most important part is still low carb, grain free, high protein.
Finally let’s talk about treats. I am not against people feeding treats, but you must remember that these must come out of your pets daily ration, not be given on top of it. Healthy treats include pieces of fruit & veg, little dried sprats, small cubes of dried liver, cubes of dehydrated meat, or even little bits of cooked meat. More importantly than feeding healthy treats think about substituting food for love! They have found that more than 80% of dogs prefer fuss from their owner to food, or like fuss and food equally. Also Dopamine (the happy hormone) is released, not by reward as some believe, but in seeking reward. Higher levels are released when a human (or animal) only gets rewarded 25-50% of the time (think gambling!). So next time you reach for a treat, maybe switch it for a good old fashioned bit of fuss.
To finish I shall say thank you for reading this rather long post. In my head it was going to be shorter but I have a lot to say on this subject & it is something I am very passionate about! Obesity is becoming an epidemic & we need to do something about it before we lose the health of our pet population forever. We’re in this together: vets, pet owners, pets and dog food companies – let’s work as a team!