Chew on This: Pets Are Pudgy Too

Like their human masters, cats and dogs in the Western world are packing on the pounds -- a quarter of these cuddly pets are obese.

A 500-page report released Monday by the National Academy of Sciences, the same group that reviews human nutrition, may help owners get their pets back on the straight and narrow.

The report was crammed with recommendations on the proper intake of fats, proteins, vitamins, minerals and carbohydrates for pets.

It also included information on cat and dog exercise, ideal cat and dog body fat indexes and the effects of herbs and other alternative remedies on canine and feline health.

By updating and disseminating the recommendations, panel members said they hoped to improve pet health and help stem the tide of obesity that is gripping the pet as well as the human population.

“Twenty-five percent of dogs and cats are overweight in our Western society,” said Donald C. Beitz, chairman of the academy’s subcommittee on dog and cat nutrition, which penned the report. “It’s a significant issue.”

The report is primarily intended for pet-food formulators, veterinarians and college educators and will also help inform the Food and Drug Administration, which oversees pet-food labeling requirements, Beitz said.

In the works for three years, the report is the first such nutrition update since 1985’s Nutrient Requirements of Dogs and 1986’s Nutrient Requirements of Cats.

Most of the dietary recommendations remained the same, but there were many small and several significant adjustments in some of the nutrient measures, panel member Quinton R. Rogers of UC Davis said.

For instance, the recommended levels of two amino acids (tyrosine and phenylalanine) were more than doubled this time around, Rogers said. This was done not over issues of growth or body mass but because of new research showing that extra intake of these substances led to improved production of black pigments -- and thus to a richer, darker coat of black fur.

Wherever possible, scientists listed minimum daily requirements and upper daily limits for nutrients.

The report offered a blizzard of tables and charts on pet caloric requirements. But the researchers distilled the information down to a few simple guidelines to identify an overweight pet. If the ribs of a dog cannot be felt and it has fat at the base of its tail, the pet is probably overweight. As for cats, “if a cat looks overweight, it is,” according to a statement from the academy.

The panel admitted many gaps in its knowledge remain. Vitamin needs of dogs, for instance, are far less well understood than those of cats, even though experiments with dogs early in the 20th century were key in identifying some human vitamins.

The effect of exercise, altitude and temperature on nutritional needs and digestion is also incomplete, although hundreds of experiments have been conducted on greyhounds running treadmills, or on quietly observing cats to record what percentage of time the animals spend sleeping.

A chapter of the new report also evaluated herbs and other, alternative medicine supplements, such as chondroitin sulfate for joint health, finding scant evidence in some cases, but some in others. It noted, for instance, that extracts of yucca were effective in curbing fecal odor.

“There are more and more alternative, complementary practitioners in the veterinary profession who are practicing these herbal, un-researched or unproven remedies,” said Bruce W. Little, executive vice president of the American Veterinary Medical Assn.

Domestic cats and dogs have significantly different dietary requirements reflecting their respective descent from wolves and wildcats. While dogs can tolerate receiving much of their protein from plant sources, cats require flesh.

The animals also have different sensitivities to nutrients. Cats, for instance, are sensitive to excesses of vitamin B. There have been instances where cats have been poisoned from being overfed tuna organs, which are rich in vitamin B.