Foods that fill you up without packing a ton of calories can help in the battle of the bulge, results of a new study suggest.

In the study, obese women who reduced the "energy density" of their diet by cutting their intake of fats and adding more fruits and vegetables lost more weight over a 12-month period, and felt less hungry, than did those who simply reduced their fat intake.

"Incorporating low calorie-dense foods into the diet is an effective strategy for lowering calories and reducing hunger when you're trying to lose weight," study co-author Dr Julia A Ello-Martin, of Pennsylvania State University in University Park, Pennsylvania, said.

"This is an approach that allows you to focus on the foods that you should be eating" rather than focusing on restricting calories, she added.

One of the reasons people don't stick to a weight-loss diet is hunger. Ello-Martin and her colleagues speculated that a diet that controls hunger by encouraging dieters to fill up on low energy-density foods may improve adherence as well as increase weight loss.

For the study, 97 obese women were randomly assigned to a group that was counselled to decrease their intake of fat or one that was told to decrease their fat intake and increase their consumption of filling, low energy-density foods, particularly fruits and vegetables. The study participants were not forced to meet any daily goals for their total caloric intake or to limit the amount of calories they consumed from fats to a specific amount.

Twelve months later, weight had come off the women in both groups, the investigators report in the American Journal of Clinical Nutrition. The women in the fruit and vegetable group, however, lost 7.9kg, in comparison to 6.4kg among the others.

The women in the fruit and vegetable group also reported experiencing less hunger than did the women who merely reduced their fat intake, study findings indicate.

Although the study lasted only one year, Ello-Martin speculates the dieters may be able to maintain their weight loss and dietary changes over a longer period.

"There is potential for people to sustain the diet and weight maintenance because it is food focused," she said. "They are getting to eat foods that are helping them not feel hungry."

What's more, she said, the study "didn't have that hideous approach of having to count calories every day."