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By DR. SWATI SHROFF, ABC News Medical Unit

Postmenopausal women hoping to control their weight may be able to help themselves out by sticking to three simple rules: lay off the meat and cheese, eat more fruits and veggies, and skip dessert and sugary drinks.

A new study, published Tuesday in the Journal of the Academy of Nutrition and Dietetics, aimed to find out how eating or avoiding specific foods made a difference in short and long-term weight loss results in women who had gone through menopause.

To accomplish this, researchers studied 481 overweight and obese postmenopausal women over a four-year period. At the beginning of the study, the women completed surveys assessing their eating in the past month and weighed themselves. The same surveys and weigh-ins were conducted again at six months, and then a final time at the four-year mark.

What the researchers found was that eating fewer desserts and fried foods, drinking fewer sugar-sweetened beverages, eating more fish, and eating less often at restaurants were all associated with short-term weight loss at six months.

But surprisingly, after four years, it found that only eating fewer desserts and drinking fewer sugar-sweetened beverages continued to be linked significantly to weight loss.

Also, those women who reported eating more fruits and vegetables and less meat and cheese experienced weight loss in the long term - even though they did not show any at the six-month mark.

Dr. Bethany Barone Gibbs of the University of Pittsburgh Department of Health and Physical Activity, who was the lead researcher, said that the findings could be a road map for many older women who hope to keep the pounds off well into the future.

"The goal is long-term weight loss, and these four behaviors were most important," Gibbs said.

The findings on the delayed benefit of limiting meat and cheese consumption may be particularly useful to these women, as short-term results appear to be limited for women who take these healthful measures.

"Maybe these things won't move the scale much at six months, but they seem to be important in the long-term," Gibbs said.

Oddly, the frequency of eating at restaurants and eating fewer fried foods did not appear to be significantly related to changes in weight at the four-year mark - an unexpected finding that the study was not designed to address further. Of note, however, is the fact that the study did not look at how often women ate at fast-food restaurants specifically, as opposed to restaurants offering healthier fare, which may have resulted in a different finding.

In its entirety, the new study may be important because weight maintenance becomes particularly challenging for women at menopause, due in large part to changes in metabolism and lifestyle.

"Their lives have changed," says Dr. Lauren Streicher, assistant professor of obstetrics and gynecology at the Feinberg School of Medicine. "They're not running around after kids, they're eating out more, they're driving more and walking less, they're moving out of their houses and into apartments."

Streicher notes that while hormonal changes in menopause may affect the distribution of weight, generally causing more abdominal weight gain, it is really the change in the body's metabolism that causes actual weight gain.

Muscle mass decreases as people age, and if it isn't replaced, fat becomes its substitute. This slows down the body's metabolic rate - the rate at which we burn calories - which makes it even more difficult to lose weight.

"Women going through menopause have a very difficult time maintaining their weight. No one has done enough research on it," says Dr. Jaques Moritz, director of gynecology at St. Luke's-Roosevelt Hospital Center. "In my practice, I have a lot of menopausal patients, and they really try to exercise and cut back on food - but they still gain weight."

And for women at this age, weight gain is more than about just appearance. Obesity is known to increase the risk of high cholesterol, high blood pressure, and type 2 diabetes - all of which increase the risk of heart disease and stroke. Excess weight is also associated with many cancers, including breast cancer.

Moritz says this study probably won't change his central message to his menopausal patients. He prepares his patients for the weight changes in advance, telling them not to get discouraged, but to keep up with dietary changes and exercise.

His advice? "Watch your weight before menopause, double up your efforts at menopause."