Las Vegas ? People looking for a way to lose weight may want to trade in pills for a pooch.

A first-of-its-kind experiment to put people and their pets on a diet and exercise program found that both lost weight and kept it off, though dogs did better than their owners and didn’t drive them crazy begging for food.

The study was funded by Hill’s Pet Nutrition, which makes Science Diet and a prescription diet dog food. Results were reported this week at the national obesity conference.

Despite its cuteness factor, the research actually was a big hairy deal, said Dr. Robert Kushner of Northwestern Medical School in Chicago, who has done obesity studies for 20 years and designed this one after Hill’s asked if he thought pets could help people lose weight and vice versa.

He and Kimberly Rudloff, a Chicago veterinarian, enrolled three groups: 56 people, 53 dogs, and 36 dogs and their owners.

The dogs ranged from pudgy poodles to husky Huskies.

People attended weekly counseling sessions at Northwestern on diet and exercise, and were encouraged to walk at least 20 minutes and limit calories to 1,400 a day. Dogs were fed the prescription diet, and target weights were set according to a “doggie BMI” or body-mass index taking into account the animal’s breed and age.

All were followed for one year.

The dog owners did slightly better than the dieters who walked and dieted alone. Overall, people lost an average of 11 pounds, or 5 percent of their body weight, in the first four months and kept it off for the next eight. The most anyone lost was 51 pounds. But the diet was less onerous and more fun for the dog-walkers.

The weight-loss for the dogs was even more effective. They lost an average of 12 pounds — 15 percent of their initial weight. One dog actually lost 35 pounds.