Pet owners are presented with an ever-increasing and more expensive array of pet foods, but the costlier varieties will not necessarily make dogs or cats healthier or happier, says a UC Davis veterinary nutritionist. Any pet food that has the nutritional claim "complete and balanced for all stages of life as determined by animal testing" should be completely satisfactory, whether the food is generic or a gourmet variety, according to Quinton Rogers, a professor of physiological science at the UC Davis School of Veterinary Medicine who has studied pet nutrition for 17 years. Although puppies, kittens and pregnant and nursing animals have special dietary needs, other healthy pets are unlikely to derive any extraordinary benefits from foods that are purported by their manufacturers to prevent disease, cure allergies or impart other special qualities, Rogers says. People should be mindful of preventive nutrition, he says, but all they need to look for on pet food labels is an indication that the food provides a "complete and balanced nutrition for all life stages." Anything beyond that for dogs and cats is unnecessary, he says. "If there's a little extra carbohydrate or protein or minerals, it's not really going to matter."