KEY POINTS:
Overindulgence in popular dry cat biscuits may be to blame for household moggies taking on Garfield-like proportions, new research shows.
Massey University scientist Dr David Thomas said cats were often not the only ones with an over-eating problem: "Obesity levels in companion animals frequently mirror that of their owners."
The ease and convenience of dry cat biscuits heightened the risk of owners perpetually topping up the dish and overfeeding their pet, said Dr Thomas, director of the university's centre for feline nutrition at Palmerston North.
Other studies have estimated that between 25 and 40 per cent of pet cats worldwide are overweight.
Dr Thomas's findings will be presented at a major nutrition conference starting at the university's Auckland campus today.
He said cats are naturally designed to eat several small, protein-packed meals a day.
The study, which set out to establish whether there is any link between dry food consumption and weight gain in cats, found that those fed solely dry biscuits got plumper but lost weight once they changed to a wet, or canned food, diet.
Sixteen adult cats bred at the centre and fed canned cat food were split into two groups.
After an initial period during which both groups were given just dry food, one group changed to canned meals and the other continued with dry biscuits. Those eating only dry food put on weight, while the group fed canned food lost weight.
Cats ate less and felt fuller more quickly eating canned food because it contained more water.
"It's harder to overfeed wet food than dry," said Dr Thomas.
But well-meaning cat owners tended to feed them dry food on demand, rather than in accordance with any measured portions, Dr Thomas said.
Cats were first domesticated by the ancient Egyptians to keep mice away from grain stores. They obtained most of the water needed for survival from eating fresh meat in a similar way to other desert carnivores.
Because dry cat food contains more starch and more carbohydrates than wet canned cat food, some have argued that a diet containing large amounts of carbohydrates is unnatural for a cat.
Carbohydrates constitute between 30 and 40 per cent of dry cat food.
Wet cat food, on the other hand, is high in protein and more similar to a natural carnivore diet.
Robert Backus, a veterinarian and assistant professor at University of Missouri-Columbia, said in other research released yesterday that weight gain, not the type of diet, is more important when trying to prevent diabetes in cats.
His team of researchers compared a colony of cats in California raised on dry food with Massey's colony of cats in New Zealand raised on canned food.
They found little difference between the two in glucose-tolerance tests.
His study also found that cats on canned or wet food diets had less of a tendency towards obesity than cats on dry food diets.
According to Professor Backus, male cats should weigh between 4.53kg and 4.98kg, and female cats should weigh between 2.49kg and 3.49kg.
Besides diabetes, overweight cats are prone to other conditions such as skin diseases, oral diseases and certain types of cancer.
- NZPA
