TUESDAY, Nov. 29 (HealthDay News) -- Dieters may want to reconsider that mid-morning snack.

In a 12-month study of 123 overweight or obese women, those who snacked between breakfast and lunch lost less weight than those who skipped a mid-morning nosh.

The finding may not relate to time of day as much as the short interval between breakfast and lunch for these snackers, explained study author Dr. Anne McTiernan, director of the Prevention Center at the Fred Hutchinson Cancer Research Center's Public Health Sciences Division.

The women may have been eating out of boredom, or for reasons other than hunger, she said. The net result is too many calories in a day.

"Snacking, per se, isn't bad, it's more what you eat and when you are snacking," she said. "If you start snacking in the morning, you might be eating more throughout the day and taking more food in."

Smart snacking can be part of a sound weight-loss plan, McTiernan noted. The timing of snacks, frequency of eating them and quality of snacks all have to be considered, she added.

The study is published in the December issue of the Journal of the American Dietetic Association. The U.S. National Cancer Institute and U.S. National Institutes of Health funded the research.

McTiernan assigned the women, aged 50 to 75, to either a diet-alone program or a diet plus exercise program. Those in the diet-alone group ate 1,200 to 2,000 calories a day, depending on their starting weight. Those in the diet and exercise group also reduced calories but, in addition, put in 45-minute workouts five times a week.

The participants were given counseling about nutrition but no special instructions about snacking.

The women recorded the time, type and frequency of meals on a normal day. The researchers evaluated calories from fat and fiber, fruit and vegetable intake, and other information.

At the study start, the average body mass index (BMI) was 31.3. (A BMI of 30 is termed obese.) Weight loss in the two groups was similar. Those in the diet-only group lost about 10 percent of their body weight and those in the diet and exercise group lost 11.6 percent after one year.

However, snacking patterns were linked with the amount of weight loss. The mid-morning snackers lost about 7 percent of their total body weight, but those who didn't snack mid-morning lost 11.5 percent, according to the report.

More women snacked in the afternoon than the morning. Snacks might be appropriate if the interval between meals is long, such as five hours or more, McTiernan said.

Commenting on the study, Connie Diekman, director of university nutrition at Washington University in St. Louis, said that appropriate snacking is key.

"The study shows that appropriate snacking can help with achievement of nutrition goals and aid weight loss," Diekman said. "While it isn't conclusive from this study, it appears morning snackers may not lose as much as those who snack later in the day. More studies are needed to assess if this connection is real, is about food choices or if it is just a difference in the individuals," she added.

"Snacking can help boost nutritional status and often helps manage emotional eating, but the key is choosing the right snack choices," Diekman explained. "Since this study was done in overweight women it would be helpful to see if similar results occur in normal-weight, postmenopausal women."

Until more research is in, McTiernan encourages dieters to limit a snack to no more than 200 calories. Healthier snacks include low-fat yogurt, string cheese or a handful of nuts, she suggested. Other good choices are non-starchy vegetables (avoid potatoes and corn), fresh fruits and whole grain crackers.

The study included only women, so the researchers can't say for sure if it applies to men. "But studies have shown calorie intake is equally important in men and women," McTiernan noted.

More information

To learn more about smart snacking, visit the American Heart Association.