The Bombay is a medium-sized, muscular cat that the breed standard describes as feeling heavier than it looks. That dense build, under a coat with no markings to show a change in outline, makes weight gain easy to miss. Measured portions and a monthly weigh-in do more for most Bombays than any special ingredient. The breed's main heart concern, hypertrophic cardiomyopathy (HCM), cannot be prevented by diet, but it can be found early.
Where the breed comes from
According to the Cat Fanciers' Association breed profile, the Bombay dates from 1966, when Kentucky breeder Nikki Horner crossed the American Shorthair with the Burmese. The standard calls for a cat that is medium in size and "neither compact nor rangy," with a rounded head and a moderately rounded muzzle. The CFA considers the breed generally healthy. It notes that some Bombays have overly teary eyes and that HCM has been found in the breed.
We found no published study of body weight or obesity rates in Bombays. The feeding advice below therefore rests on what is known for cats in general, applied to a heavy-boned indoor breed.
How much to feed an adult Bombay
The Merck Veterinary Manual gives the usual starting estimate. Resting energy requirement (RER), in kcal a day, is 70 multiplied by body weight in kilograms raised to the power 0.75. Neutered adult cats are then fed about 1.2 times RER, intact adults 1.4 times, and adults prone to obesity 1.0 times. Rounded to the nearest 5 kcal:
| Ideal body weight | Neutered adult | Intact adult | Prone to obesity |
|---|---|---|---|
| 3 kg | 190 kcal | 225 kcal | 160 kcal |
| 3.5 kg | 215 kcal | 250 kcal | 180 kcal |
| 4 kg | 240 kcal | 275 kcal | 200 kcal |
| 4.5 kg | 260 kcal | 305 kcal | 215 kcal |
| 5 kg | 280 kcal | 330 kcal | 235 kcal |
Treat the table as a first guess. Work from the cat's ideal weight, not its current one, and adjust the amount over several weeks by body condition. Most pet Bombays are neutered and live indoors, so the neutered or obesity-prone column is the usual place to start. Kittens are different: Merck puts growing kittens at about 2.5 times RER, or allows free-choice feeding.
Checking a black cat's condition. Use your hands, since the coat hides shape in photos and at a glance. The ribs should be easy to feel under a thin layer of fat. From above there should be a slight waist behind the ribs, and the belly should not hang. A kitchen or baby scale once a month catches the slow gains that hands miss: 300 g on a 4 kg cat is more than 7% of its weight.
A neutered Bombay with an ideal weight of 4 kg starts at roughly 240 kcal a day, and many need less. For portions worked out from your own cat's weight and routine, get a personal plan.
Get Personalized Guidance →Keeping weight off
Extra weight has real costs for a cat. A 2024 review in the Journal of Feline Medicine and Surgery links overweight and obesity with musculoskeletal changes, insulin resistance and type 2 diabetes, skin disorders, and kidney and urinary tract disease. It names a sedentary indoor life and food available in several portions through the day among the risk factors. Neither is specific to the Bombay, and both are within an owner's control.
- Weigh the food. A kitchen scale is more accurate than a scoop, particularly for dry food, where a small overfill carries a lot of calories. Split the day's amount into two or more meals instead of leaving a bowl down.
- Use wet food for volume. Merck gives the moisture of canned foods as 60% to more than 87%, against 3% to 11% for dry food. A wet meal is larger for the same calories, and cats eating mostly canned food drink less because the food supplies the water.
- Count treats. A common guide keeps them to about 10% of daily calories, around 24 kcal for a cat on 240 kcal.
- Make the cat work. Puzzle feeders and scattered portions of dry food slow eating and add movement. Two or three short play sessions with a wand toy help too.
A weight-control food supplies the same nutrients in fewer calories, and protein should stay adequate so the cat loses fat rather than muscle. If a Bombay is already overweight, ask the vet for a target weight and a rate of loss. Cats that stop eating or lose weight quickly can develop fatty liver disease, so crash diets are not an option.
HCM and what food can do
Hypertrophic cardiomyopathy thickens the muscular wall of the heart so that it fills poorly. It is the most common heart disease in cats, and we found no published figure for how often it occurs in Bombays. Its course varies a great deal. The ACVIM consensus guidelines on feline cardiomyopathy note that some cats with cardiomyopathy have a normal life expectancy, while others develop congestive heart failure, a blood clot that blocks an artery (arterial thromboembolism), or die suddenly.
No diet or supplement has been shown to prevent HCM. Three points about food are worth getting right:
- Taurine. Merck states that a lack of taurine can cause dilated cardiomyopathy and retinal degeneration in cats. That is a different heart disease from HCM. Complete and balanced commercial foods, wet or dry, are made to supply enough, so a healthy cat eating one does not need extra taurine. The risk lies in vegetarian or badly formulated home-made diets, because plant proteins contain none.
- Supplements. Fish oil, L-carnitine and similar products sold for the heart have no published evidence of preventing HCM in cats.
- Salt. Ordinary cat food is fine for a healthy cat. Salty human foods such as ham and cheese make poor treats anyway. A cat already diagnosed may be given a diet or medication by its vet, and that plan comes first.
Many cats with HCM show nothing until the disease is advanced. A heart murmur or an irregular rhythm heard at a routine check is often the first sign, and an echocardiogram (heart ultrasound) confirms it. Breeding cats are the obvious candidates for screening. Fast or labored breathing at rest, open-mouth breathing, or sudden pain or weakness in the back legs need an emergency vet.
Head shape, teary eyes and the Burmese head defect
The Bombay standard asks for a moderate muzzle, not a flat face, though cats from lines with more Burmese type can be shorter in the face. For those cats a wide, shallow dish is easier than a deep bowl, and flat kibble may be easier to pick up than round pieces. The teary eyes mentioned by the CFA need gentle wiping with a damp cotton pad. Thick yellow or green discharge, squinting or a red eye is a reason to see a vet.
The Burmese side of the breed also carries a genetic risk worth knowing about before buying a kitten. In the Burmese head defect, a small deletion in the ALX1 gene behaves as a co-dominant trait. One copy shortens the face. Two copies cause a severe malformation of the skull and face that is incompatible with life. Langford Vets' genetic testing service lists the Bombay among the breeds for which the DNA test is relevant. Ask whether both parents were tested, since two carriers mated together can produce affected kittens.
Teeth
Dental disease is common in adult cats of all breeds. We found no evidence that Bombays are more prone to it than other cats. Daily or near-daily brushing with a cat toothpaste is the most effective home care. Dental diets and treats vary in what they do, and products carrying the Veterinary Oral Health Council (VOHC) seal have trial data behind their plaque or tartar claims. Dental treats count toward the day's calories. An oral exam at each annual visit picks up gum disease and tooth resorption, a painful breakdown of the tooth, before the cat starts eating less.
Sources
- Bombay. The Cat Fanciers' Association.
- Nutritional Requirements of Small Animals. Merck Veterinary Manual.
- Overweight and obesity in domestic cats: epidemiological risk factors and associated pathologies. Journal of Feline Medicine and Surgery, 2024.
- ACVIM consensus statement guidelines for the classification, diagnosis, and management of cardiomyopathies in cats. Journal of Veterinary Internal Medicine, 2020.
- Aristaless-Like Homeobox protein 1 (ALX1) variant associated with craniofacial structure and frontonasal dysplasia in Burmese cats. Developmental Biology, 2016.
- Burmese Head Defect. Langford Vets Diagnostic Laboratories.
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