TUESDAY, Jan. 30 (HealthDay News) -- Whether you eat fewer calories or burn them off through exercise, the effect on body composition and fat distribution is the same, a new study says.

Researchers at the Pennington Biomedical Research Center in Baton Rouge, La., found that dieting alone is as effective as a combination of diet and exercise at cutting weight and fat -- as long as calories consumed and burned equal out.

Their study also indicated that adding exercise to a weight-loss program doesn't change body composition and abdominal fat distribution. That challenges the theory that specific exercises can reduce fat in certain areas. For example, some exercises are supposed to specifically target abdominal fat.

"It's all about the calories. So long as the energy deficit is the same, body weight, fat weight, and abdominal fat will all decrease in the same way," study senior author Dr. Eric Ravussin said in a prepared statement.

He and his colleagues studied 35 overweight people. They were divided into three groups: One group went on a diet that reduced their caloric intake by 25 percent (550 to 900 fewer calories a day); the second group reduced their caloric intake by 12.5 percent and increased their physical activity to burn 12.5 percent more calories.

The people in the third (control) group were put on a healthy diet designed to maintain their body weight.

After six months, the people in both the calorie-restricted and the calorie reduction/exercise groups had lost about 10 percent of their bodyweight, 24 percent of their fat mass, and 27 percent of their abdominal fat. However, their distribution of body fat remained the same.

"The inability of the interventions to alter the distribution of fat suggests that individuals are genetically programmed for fat storage in a particular pattern and that this programming cannot easily be overcome," Ravussin said.

While dieting alone can reduce weight, the researchers noted that exercise also improves aerobic fitness, which has many other health benefits.

"For overall health, an appropriate program of diet and exercise is still the best," Ravussin said.

The study is published in the Journal of Clinical Endocrinology & Metabolism.

More information

The American Academy of Family Physicians has more about weight control.