WASHINGTON -- The old wives' tale holds that people start to look like their pets. Turns out it's the other way around: America's pets are starting to look like Americans -- overweight.
Whether it's round hounds or corpulent cats, as many as one-fourth of cats and dogs in the Western world are overweight, according to the National Research Council, an arm of the National Academies.
It's the council's first update since 1986 of its "Nutrient Requirements of Dogs and Cats" and, while aimed at veterinarians, pet food makers and scientists, the 500-page report also contains useful pointers for people with pets.
Kathryn Michel, a veterinary nutritionist at the University of Pennsylvania, said she has noted more overweight pets in recent years, particularly cats, and the problem seems to occur at younger ages than in the past.
"A big problem that people don't always recognize," she said, is that pets "are members of our families, we show them affection, and one way is by sharing food and giving treats."
Just a piece of biscuit
People don't have to ignore those hopeful eyes looking up, she says, just be careful. A piece of a biscuit will help bond with the animal just as much as the whole biscuit.
Like people, obese pets have a greater risk of developing such diseases as diabetes, heart disease and other health problems, said Donald C. Beitz, chairman of the committee that prepared the report.
Beitz, a professor of animal science at Iowa State University, said the new study adds a chapter on physical activity for pets and points out that the council has established a Web site for pet owners to learn more about nutrition for their animals, how to determine if they are overweight and suggestions for helping them lose weight.
The Web site is national-academies.org/petdoor.
"Obesity is estimated to occur in 25 percent of dogs and cats in Westernized societies," the report states, noting that obesity increases with the age of the pet and occurs more frequently in neutered animals.
Cats, the report notes, are descended from carnivores, and their digestive system is designed for absorbing nutrients from animal-based proteins and fats.
A cat should not be fed a vegetarian diet because it could result in harmful deficiencies of certain amino acids, fatty acids and vitamins, the report says.
While dogs prefer animal-based food, they can survive on vegetarian diets as long as they receive sufficient protein and other nutrients, the report adds.
Cats snack, dogs gorge
Cats like to snack, the report found, while dogs are gorgers.
In tests where animals were allowed to eat whenever they wanted, cats ate smaller meals, more often, than dogs. Cats ate 12 to 20 meals, spread out through day and night, while dogs ate seven or eight times, mostly in the daytime.
The report stresses that fresh water always should be available to dogs, especially during exercise, to prevent overheating.
It's fine to feed an adult dog just one or two times a day, but puppies need to eat two to three daily meals. Puppies, kittens and lactating dogs and cats need more daily calories, as may pets that are sick or injured.
Cats don't drink as much water as dogs, perhaps because cats evolved as desert animals. Given a choice, however, they usually will choose moist over dry food. The weak thirst of cats puts them at higher risk for urinary tract stones.
The report says owners should be able to feel the ribs of a healthy dog, and it should have a discernible waist without fat deposits. However, if the ribs and pelvic bones can be seen, it's too thin.
If a cat looks overweight, it is, the report says. There should be no heavy fat deposits on the back, face or limbs or a rounding of the abdomen.
Help them trim down by offering less of their usual food and cutting back on or eliminating table scraps. Also, within limits, offer foods with more fiber.