Sphynx cat nutrition: calories, oily skin and raw food risks

The health problem that matters most in the Sphynx is hypertrophic cardiomyopathy (HCM), a thickening of the heart muscle, and no diet prevents it. Food still matters for this breed in other ways. A cat with no coat loses heat faster, its skin collects oil and yeast that fur would otherwise hide, and a raw or home-made diet that goes wrong shows up quickly in a growing kitten.

Calories for a cat without a coat

Fur traps a layer of still air against the skin. Without it, a Sphynx in a cool room loses more body heat than a coated cat, and producing heat costs energy. Breed guides often say a Sphynx needs 20% or more extra calories. We found no study that has measured this, so treat any fixed percentage as a guess. A Sphynx kept in a warm house may need little more than any other cat.

The practical starting point is the standard calculation in the Merck Veterinary Manual. 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 then fed about 1.2 times RER, an intact adult 1.4 times, a cat that gains weight easily 1.0 times, and a kitten 2.5 times. Rounded to the nearest 5 kcal:

Merck adds that two animals of the same weight can differ by as much as 30% in what they need, which is a wider range than any breed adjustment. So the scale decides. A workable routine is to weigh the cat every two weeks while you settle on a portion, then monthly, and to change the amount by about a tenth at a time. In a Sphynx the body shape is easy to judge by eye: ribs should be easy to feel but not stick out, with a visible waist behind them. A cat losing weight on a generous ration needs a vet check, since hyperthyroidism, diabetes and other illnesses cause weight loss too.

Keeping the house warm, and giving the cat a heated bed or a fleece to burrow into, lowers the energy spent on heat. Many owners split the day's food into three or four meals. That suits a cat that grazes, but the total counts more than the number of meals.

Oily skin and yeast

Skin oil (sebum) in a coated cat spreads along the hairs. On a Sphynx it stays on the skin, so the cat feels slightly greasy, leaves marks on pale fabric and builds up brown waxy material in skin folds, around the claws and in the ears. Skin like this carries a lot of yeast. In a study of skin yeast in Sphynx cats, Malassezia was grown from 26 of 32 Sphynx cats (81%) and from none of 10 ordinary shorthaired cats. The five Sphynx cats with greasy seborrhea all carried Malassezia pachydermatis at several sites. Yeast numbers in the armpits, groin and claw folds were significantly higher than in the shorthaired cats.

High yeast numbers are normal for the breed, and the evidence for managing them points to the skin rather than the bowl. Regular bathing with a mild cat shampoo, and cleaning claw folds and ears, removes the oil. A vet can prescribe an antifungal wash when there is redness, odor, itching or crusting. Claims that cutting carbohydrates or sugar in the diet reduces yeast on the skin have not, as far as we could find, been tested in cats.

What diet can and cannot do for skin

A cat eating a complete and balanced commercial food gets the vitamin A, zinc, essential fatty acids and B vitamins its skin needs. Deficiencies cause skin and coat changes, but Merck notes that nutritional disease is rare in cats fed such diets and occurs most often in cats on unbalanced home-made diets. Adding more of a nutrient does not help a cat that already has enough, and vitamin A is a real hazard. Merck notes that cats are more sensitive than dogs to excess vitamin A and that feeding only liver can cause vitamin A toxicity. Skip liver-heavy treats and do not add vitamin A or cod liver oil without a vet's advice.

Fish oil, a source of the omega-3 fats EPA and DHA, is widely given for skin. There are no trials in Sphynx cats, and the right dose depends on the cat's weight, its food and the reason for giving it. Ask the vet for a dose.

Raised spots and red patches

Sphynx and Devon Rex cats are overrepresented in reports of cutaneous mastocytosis, a skin disease caused by mast cells and often called urticaria pigmentosa. In a series of 13 affected cats from a referral dermatology practice, nine were Sphynx and two were Sphynx and Devon Rex crosses. Lesions ranged from raised bumps and wheals on the head, neck and armpits to crusted red patches and, in longer-standing cases, thickened dark skin. The authors noted that one form carried a poorer outlook. This needs a diagnosis by a vet, often with a biopsy, and it is treated medically. No diet has been shown to control it.

Blackheads and crusts on the chin (feline acne) also show up clearly on a hairless cat. Washing the food bowl after every meal and wiping the chin afterwards are sensible, cheap habits, though evidence that bowl material causes acne is thin.

Digestion, raw food and the missing hairballs

Sphynx cats are often described as having sensitive stomachs. We found no study comparing digestive disease in Sphynx cats with other breeds. What is well established is the risk of an unbalanced diet. A case report in JFMS Open Reports described a five-month-old Sphynx kitten that the breeder had fed only raw chicken. The kitten had thin, weak bones, a fractured shin and eye damage consistent with central retinal degeneration, which can result from taurine deficiency. Its vets managed it with a complete canned kitten food and added taurine. Raw diets can be formulated properly, but meat alone is not a diet for a cat.

For day-to-day digestion:

• Change foods gradually over about a week, mixing increasing amounts of the new food into the old.
• Change one thing at a time when stools are soft, so the cause can be identified.
• See a vet for diarrhea lasting more than a day or two, repeated vomiting, blood in the stool or weight loss. Food intolerance is one possible cause among several, and parasites, infections and inflammatory bowel disease look similar.

Hairballs from swallowed fur are unlikely in a cat with only fine down, so hairball-control foods have no obvious purpose for a Sphynx. That also means a vomiting Sphynx cannot be written off as having hairballs. Repeated vomiting has a cause worth finding.

Heart disease and screening

HCM is common in the breed. In a screening study of 114 Sphynx cats with an average age under three years, 23 had HCM and a further 16 had congenital heart disease, so about a third had some abnormality on the echocardiogram. HCM on its own affected about one in five, not the one in three sometimes quoted. Screening in older cats found more. A New Zealand study of 55 apparently healthy Sphynx cats, at a median age of 5.8 years, found HCM in 40%, and three affected cats died of heart failure during the study. That study also tested for a gene variant in ALMS1 that has been linked to HCM in Sphynx cats. Seven in ten cats carried it, but in that population it did not predict which cats had HCM, so a genetic test cannot replace a scan.

Food cannot prevent HCM, but two nutrition points are worth being clear about.

• Taurine deficiency causes a different heart disease. According to Merck, a lack of taurine can cause dilated cardiomyopathy, in which the heart muscle becomes thin and weak, and retinal degeneration. Any complete and balanced cat food contains enough. There is no evidence that extra taurine treats or prevents HCM.
• Supplements sold for heart health, such as coenzyme Q10 and fish oil, have no published evidence of preventing or slowing HCM in cats. A cat already diagnosed may be prescribed medication and a specific diet by its vet, and that plan comes first.

Many cats with HCM look healthy, as the New Zealand cats did. An echocardiogram, an ultrasound of the heart, is the test that finds it. Both studies above rescanned cats over time, because a normal result in a young cat does not rule out HCM later, so ask the vet how often to repeat it. Fast or labored breathing at rest, open-mouth breathing, collapse, or sudden pain or weakness in the back legs need emergency care. The last can be a blood clot thrown from the heart.

A feeding plan that follows the evidence

• A complete and balanced commercial food for the cat's life stage, wet, dry or both. Canned food is 60% to more than 87% water against 3% to 11% for dry, which helps a cat that drinks little.
• Portions set by body weight using the calculation above, then adjusted by weighing, not by a breed percentage.
• A warm house and bed, which cut the energy spent on staying warm.
• No unbalanced raw or home-made diet. If the cat is to eat home-made food, have the recipe formulated by a board-certified veterinary nutritionist.
• Skin handled at the skin, with bathing and cleaning, and supplements only on a vet's dose.
• Regular heart screening by echocardiogram, planned with a vet.

Sources

1. Nutritional Requirements of Small Animals. Merck Veterinary Manual, 2023.
2. Cutaneous carriage of Malassezia species in healthy and seborrhoeic Sphynx cats and a comparison to carriage in Devon Rex cats. Journal of Feline Medicine and Surgery, 2009.
3. Feline maculopapular cutaneous mastocytosis: a retrospective study of 13 cases and proposal for a new classification. Journal of Feline Medicine and Surgery, 2019.
4. Metabolic bone disease and central retinal degeneration in a kitten due to nutritional inadequacy of an all-meat raw diet. JFMS Open Reports, 2015.
5. Prospective echocardiographic and tissue Doppler screening of a large Sphynx cat population: reference ranges, heart disease prevalence and genetic aspects. Journal of Veterinary Cardiology, 2012.
6. Prevalence of hypertrophic cardiomyopathy and ALMS1 variant in Sphynx cats in New Zealand. Animals, 2024.