Naturally slimmer vs naturally bulkier cats

Just like some humans, some cat breeds are prone to unintentional weight gain, while others are very active and playful and naturally slimmer. While it mostly it comes down to breed, some health factors may impact weight gain or weight loss.

Differences in breeds

Cats come in all shapes and sizes with different body types, coats and lengths. Every cat owner should monitor their cat’s weight and condition and take her for an annual veterinary examination. It is difficult to determine what the normal weight is for cats, due to the variations in breeds and individuals. A cat gains weight when she eats more calories than she needs. Weight loss is more complicated, as there can be several reasons why your cat is losing weight. As your cat ages, she will be more likely to show changes in weight. Some seniors pick up weight, while others slim down.

Fat elements

More than half of cats are overweight and 25% are obese. Obesity is usually caused by excessive food intake and insufficient exercise. It also depends to a large extent on the cat’s individual characteristics. Obesity is more common in older, less active or spayed females whose weight is not well managed. The average domestic shorthaired cat should weigh between 3.6 and 4.5kg, depending on the breed and individual.

Some ways to determine if your cat is overweight:

  • Place your hand on either side of your cat and firmly stroke her sides – you should be able to feel her ribs. If you can’t feel her ribs, your cat is overweight.
  • Stand above your cat and look down at her. Your cat’s waistline should be detectable as a slight indentation just behind her ribs.
  • A swinging pouch between your cat’s hind legs is a sign that your cat is overweight.
  • Your cat’s anal area should look clean. Some obese cats have trouble grooming this area.
  • A greasy patch, matting of fur or flaking of skin down the midline of a cat’s lower back can also indicate obesity.

If you think your cat is overweight, consult your veterinarian to determine if there are any other medical problems before starting a weight-reduction programme.

Slim elements

Many times, people don’t notice a huge difference in their cats’ weight, especially in the longhair breeds, until they pick them up. Physical signs that your cat is underweight include:

  • The cat feels very bony. Ribs on an underweight cat will be felt when you run your hands along the flanks and spine.
  • The hind legs will appear bony when significant weight loss has occurred.
  • There is a significant pinching in behind the ribs.
  • Obvious loss of muscle mass. Even slender breeds should have good muscle definition, particularly around the shoulders.

Causes of weight loss

Weight loss is usually a sign that there is an underlying problem. Cats can develop anorexia, sometimes brought on by a health issue, stress or a psychological disorder. Gastrointestinal issues, food allergies or a new intolerance could also be culprits.

Possible reasons may include:

  • Impaired food intake – poor appetite, inadequate diet
  • Malabsorption – an impairment of food absorption such as when there is a lack of digestive enzymes
  • Nutrient losses – vomiting or diarrhoea
  • Changed nutritional requirements – organ dysfunction, hyperthyroidism or pregnancy
  • The environment can contribute to weight loss – ensure quiet and uninterrupted mealtimes

Illnesses leading to weight loss may include:

  • Kidney disease
  • Infection
  • Diabetes mellitus
  • Feline immunodeficiency virus, feline infectious anaemia or feline leukaemia virus
  • Liver disease
  • Cancer
  • Dental problems
  • Parasitic worms
  • Heartworm

How much should your cat eat?

The best way to calculate your cat’s daily resting energy requirements (RER) is with this formula: 30 x your cat’s body weight in kilos + 70 = your cat’s RER

  • Average cat who weighs 5kg: 30 x 5kg + 70 = 220
  • Obese cat who weighs 6.5kg: 30 x 6.5kg + 70= 265
  • Underweight cat who weighs 3.5kg: 30 x 3.5kg + 70 = 175


To calculate your cat’s daily energy requirements (DER):

  • A 5kg cat who is on a maintenance diet and doesn’t need to gain or lose weight: 220 RER x 1.2 = 264 calories per day
  • A 1kg kitten who is growing: 100 RER x 2.5 = 250 calories per day
  • A 6.5kg obese cat who needs to lose weight: 265 RER x 0.8 = 251 calories per day

As your cat loses weight, her RER will drop and you should adjust this formula. The same goes for kittens: a kitten’s weight will gradually increase, and therefore you will need to recalculate her DER weekly.

Treatment of overweight cats

The most effective weight-loss plans involve increasing activity and feeding fewer calories.

  • Feeding a cat the same amount of food delivered in smaller meals helps to burn calories more efficiently.
  • Feed less of her regular food per day, paired with increased activity.
  • Gradually switch her to a low-calorie food.

Chubbier cat breeds

The following breeds are more likely to be chubby:

  • Sphynx
  • Birman
  • Exotic Shorthair
  • British Shorthair
  • Manx
  • Persian

Slimmer cat breeds

These breeds are usually very inquisitive, playful, active and acrobatic:

  • Abyssinian
  • Somali
  • Bengal
  • Cornish and Devon Rex
  • Balinese
  • Egyptian Mau
  • Siamese
  • Oriental Shorthair


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