Last Updated: 2008-07-08 14:20:06 -0400 (Reuters Health)

NEW YORK (Reuters Health) - People who keep a journal to track their eating habits may be more successful at shedding pounds, according to research published Tuesday.

In a study of nearly 1,700 overweight adults in a weight-loss program, researchers found that those who wrote in a "food diary" every day lost twice as much weight over six months as those who did not keep a journal.

The findings, published in the American Journal of Preventive Medicine, suggest that dieters who add some extra tools to their repertoire may be more successful.

"The more food records people kept, the more weight they lost," Dr. Jack Hollis, the lead researcher on the study, said in a statement.

"It seems that the simple act of writing down what you eat encourages people to consume fewer calories," explained Hollis, a researcher at Kaiser Permanente's Center for Health Research in Portland, Oregon.

Of course, a food journal is not all it takes to win the battle of the bulge. Men and women in the study regularly attended group sessions with nutrition and behavioral counselors who encouraged them to cut calories, eat more fruits and vegetables and exercise regularly, among other healthy measures.

As part of those efforts, participants were asked to keep daily records of their food and beverage intake, as well as how many minutes they spent exercising.

After six months, the researchers found, the study group had lost an average of 13 pounds, and the majority had lost at least 9 pounds.

Overall, men and women who'd maintained a food diary tended to be more successful than those who had not kept a journal. Similarly, the more participants exercised, the greater their weight loss, on average.

Food diaries do not have to be formal, according to the researchers. They say that simply listing the foods eaten each day can help people become aware of their habits and make changes for the better.

SOURCE: American Journal of Preventive Medicine, August 2008.