Consumers can buy food made for old and young dogs, large and small dogs and dogs battling the bulge.

Now comes food and treats based on a dog's lifestyle, bite strength and breeding.

Royal Canin recently launched what it says is the first "lifestyle" dog food: Indoor Adult 21 for small dogs who live indoors. The food is lower in fat to battle obesity and has a little something extra to reduce stool odors, says spokeswoman Ann Hudson.

Royal Canin has nine dog foods specially made for certain breeds, including products introduced last year for Shih Tzus, dachshunds and Chihuahuas.

While a Labrador retriever benefits from more protein and less fat to battle obesity, the picky-eating Chihuahua needs flavor enhancers. The poodle gets sulfur-containing amino acids to help hair curl, and the square-jawed bulldog gets an S-shaped kibble for easier grasping.

"Just as in human nutrition, we find something new on a regular basis," says Amy Dicke, veterinarian at Iams, which is owned by Procter & Gamble and sells the Iams and Eukanuba brands.

"Consumers love to target their dog," Dicke says.

They also spend. Dog food and treat sales will be $10 billion this year in the United States, says researcher Euromonitor International. Premium dog food is expected to account for 50 percent of U.S. dog food revenue this year, up from 35 percent in 1998, it says.

Dental treats Greenies already come in five sizes for different-sized dogs. This fall, they'll come in two textures: softer for smaller dogs and harder for larger dogs.

The goal is to get the dog to chew longer so teeth get a better cleaning, says Tiffany Bierer, nutritional expert at Mars Petcare USA, which owns Greenies. To calculate bite strength, Mars measured skull shapes and teeth positions.

The Greenies packaging advises consumers that gulping can be harmful, even fatal. Some dogs have died after undigested Greenies blocked intestines. Mars says reports of problems are rare and that 850 million Greenies have been sold since their 1998 launch.

The Association of American Feed Control Officials establishes nutritional levels for pet food. But consumers spend more for premium products. A recent price check in the San Francisco Bay Area showed a 5-pound bag of Royal Canin Lab food cost $11.99 at a specialty food store, while an 8.8-pound bag of Purina Dog Chow was $9.99 at a supermarket.

Texas veterinarian Bob Rogers urges consumer caution. Some foods are based on excellent science, but others are just marketing-driven, he says. "I don't know who to believe," he says.

Not even Royal Canin says every breed needs its own food. After much research, it has yet to find that beagles need anything extra they can't get in Royal's main product line, it says.