British Shorthair nutrition and the breed's weight problem

Weight is the nutrition problem to plan for in a British Shorthair. In VetCompass Australia records of British Shorthairs seen in first-opinion clinics from 2008 to 2017, 48% were classified as overweight, and neutered males and females were overweight on average. The breed's heavy, round build makes extra fat easy to miss, and the second breed issue, hypertrophic cardiomyopathy (HCM), is a heart disease that food cannot prevent but screening can find early.

Why British Shorthairs gain weight

The Australian finding is not isolated. A study of 4,020 cats at a cat-only clinic in Sydney, with body condition scored at more than 15,000 visits, found that British Shorthairs and mixed-breed cats were more likely than other cats to be overweight. Middle age, 7 to 11 years, was another risk factor. Purebred cats in general were more likely to be underweight, with the British Shorthair and the Burmese as the exceptions.

We found no study that explains why the breed runs heavy. The usual explanations are a calm, indoor lifestyle, a stocky frame that hides fat, and owners who read a round cat as a typical one. Neutering matters too: in the Australian records, intact males were the only group whose average body condition was ideal; neutered cats of both sexes and intact females averaged overweight.

The same Australian study found something that deserves attention in kittens. Cats weighing 3.3 kg or more at any point in their first year had much shorter survival afterwards. By 6.6 years of age, 20% of that group had died or been euthanized, while in cats that stayed under 3.3 kg that point was not reached until 12.3 years. The records cannot say why, and heavier young cats may differ in ways the study did not measure, such as sex or illness. It is still a reason not to push a kitten toward a big adult size with extra food.

How much to feed

Calorie control matters more for this breed than any ingredient or supplement. The Merck Veterinary Manual gives the standard starting point. Resting energy requirement (RER), in kcal per day, is 70 multiplied by body weight in kilograms raised to the power 0.75. A neutered adult cat is fed about 1.2 times RER, an intact adult 1.4 times, and an adult prone to obesity 1.0 times. Rounded to the nearest 5 kcal:

Given the breed's record, the neutered or obesity-prone column is the sensible place to start for most pet British Shorthairs. Merck notes that animals of the same weight can differ by as much as 30% in what they need, so the table is only a first estimate. Use the cat's ideal weight, not its current weight, if it is already overweight. For a cat that needs to lose weight, ask the vet for a plan, because cats should lose weight slowly.

Feeding habits that keep weight off

• Weigh the food. A kitchen scale is more accurate than a scoop, especially for dry food, where a small overfill carries many calories.
• Feed measured meals rather than leaving a bowl down all day. Two or more meals suit most adults; several small portions, some in puzzle feeders, suit a cat that begs.
• Count treats in the day's total. Keep them to a small share of the day's calories; a single commercial treat can be a noticeable part of a 240 kcal day.
• Weigh the cat monthly. Changes of a couple of hundred grams are hard to see on a 5 kg cat but show on a scale. Stand on bathroom scales with and without the cat if there is no pet scale.
• Play daily. Short wand-toy sessions add activity for a cat that will not exercise itself.

A food labeled for neutered or indoor cats, or a vet-prescribed weight-loss diet, can help by supplying the same nutrients in fewer calories. Protein should stay adequate during weight loss, since the aim is to lose fat, not muscle. For adult maintenance AAFCO sets a minimum of 26% protein on a dry matter basis, and many weight-control foods go well above that.

Why the extra weight matters

A 2024 review in the Journal of Feline Medicine and Surgery lists the conditions linked to overweight and obesity in cats. They include musculoskeletal changes, insulin resistance and type 2 diabetes, skin disease, and kidney and urinary tract disease. Obesity can make a cat more susceptible to these conditions, or bring an underlying one to the surface. In a heavy breed, reluctance to jump, a matted or greasy coat along the back where the cat can no longer reach to groom, and more drinking or urinating are all signs to raise with a vet.

HCM in the breed

Hypertrophic cardiomyopathy thickens the muscular wall of the heart, so the heart fills poorly. It can lead to heart failure, blood clots and sudden death. In a Danish study of 329 British Shorthairs screened by echocardiography, 8.5% had HCM, at a median age at diagnosis of only 2.7 years. Males were affected far more often: 20.4% of males against 2.1% of females. The authors strongly recommended echocardiographic screening in the breed, particularly for cats used in breeding.

No diet or supplement has been shown to prevent HCM. Some points about food are still worth being clear on:

• Taurine. Merck notes that a lack of taurine causes dilated cardiomyopathy, a different disease in which the heart muscle becomes thin. Every complete and balanced cat food provides enough. Extra taurine does not treat HCM.
• Salt. Standard cat foods are fine for a healthy cat. Salty human foods such as ham, deli meats and cheese are best avoided as treats in any case.
• Supplements. Fish oil and other products sold for heart health have no published evidence of preventing HCM in cats. A cat with a diagnosis may be prescribed medication and dietary changes, and those take priority.

Many cats with HCM show no signs until the disease is advanced. A heart murmur or an abnormal rhythm at a routine check is a common first clue, and an echocardiogram confirms it. Fast or labored breathing at rest, open-mouth breathing, or sudden pain and weakness in the back legs are emergencies.

Joints and mobility

Keeping a British Shorthair lean is the most practical thing an owner can do for its joints. Arthritis in cats is easy to miss because cats rarely limp. Instead they stop jumping onto high surfaces, use the litter tray less neatly, groom less, or sleep in lower places. These changes deserve a vet visit, since effective pain relief is available. Glucosamine, chondroitin and fish oil products are sold for cat joints, but the evidence for them is limited, and a supplement should not replace an examination.

Teeth

Dental disease is common in adult cats of every breed, and we found no evidence that the British Shorthair is more affected than others. Daily or near-daily brushing with a cat toothpaste is the most effective home care. Dental diets and treats vary, and products with the Veterinary Oral Health Council (VOHC) seal have trial data behind their plaque or tartar claims. Remember that dental treats carry calories. A mouth examination at every annual visit catches gum disease and tooth resorption, a painful condition in which the tooth structure breaks down, before the cat stops eating.

Sources

1. Bodyweight and body condition scores of Australian British shorthaired cats, 2008-2017. Frontiers in Veterinary Science, 2023.
2. Risk factors for underweight and overweight in cats in metropolitan Sydney, Australia. Preventive Veterinary Medicine, 2017.
3. Nutritional Requirements of Small Animals. Merck Veterinary Manual, 2023.
4. Overweight and obesity in domestic cats: epidemiological risk factors and associated pathologies. Journal of Feline Medicine and Surgery, 2024.
5. Prevalence of hypertrophic cardiomyopathy in a cohort of British Shorthair cats in Denmark. Journal of Veterinary Internal Medicine, 2011.