Overeating is the main reason why cats become overweight. As with people, when a cat consumes more calories than it uses, its body stores those excess calories as fat. The more fat that accumulates, the heavier your cat becomes.

The amount of exercise or activity your cat gets makes a big difference to how much he or she weighs. Less activity means a greater risk of becoming overweight.

Mixed-breed cats, rather than pure breed, have a greater tendency to put on extra weight and become obese.

When a cat consumes more calories than it needs for a long period of time, it can lead to obesity. A cat is generally considered obese when its body weight exceeds its ideal weight by 20 percent or more. The risk of obesity increases in pets between the ages of 6 and 12 years, and in pets that have been spayed or neutered.

A fit cat is healthy - and happy. Being the ideal weight allows your cat to move around without difficulty, and get much more out of life. Slim cats are far less likely to suffer from weight related illnesses like heart disease, diabetes and arthritis and joint problems.

Whatever the cause of your pet's weight gain, it is always advisable to seek the advice and support of your veterinarian.