July 13, 2012 — Dietary self-monitoring, preparing meals at home, and eating meals at regular intervals may improve 12-month weight loss among postmenopausal overweight-to-obese women, according to a dietary weight loss intervention study published online July 13 in the Journal of the Academy of Nutrition and Dietetics
"When it comes to weight loss, evidence from randomized, controlled trials comparing different diets finds that restricting total calories is more important than diet composition such as low-fat versus low-carbohydrate," senior author Anne McTiernan, MD, PhD, director of the Fred Hutchinson Cancer Research Center's Prevention Center in Seattle, Washington, said in a news release. "Therefore, the specific aim of our study was to identify behaviors that supported the global goal of calorie reduction."
Behaviors evaluated in this study were self-monitoring through self-weighing and keeping a food journal, as well as eating behaviors including dietary intake, diet-related weight-control strategies, and meal patterns. Using generalized linear models allowing adjustment for potential confounders, the investigators studied the associations of these behaviors with weight loss in a sample of 123 postmenopausal overweight-to-obese, sedentary women enrolled in a 12-month dietary weight loss intervention.
Participants were aged 50 to 75 years who had been part of a year-long, 4-group, randomized controlled weight loss trial called the Nutrition and Exercise for Women Study. Participants in that original trial were randomly assigned to 4 different groups: diet alone, exercise alone, exercise plus diet, or control. For the purpose of this ancillary study, only the women from the diet-alone and diet-plus-exercise groups were evaluated. The women completed questionnaires regarding dietary intake, eating-related weight-control strategies, self-monitoring behaviors, and meal patterns. To determine dietary change from the beginning to the end of the study, participants also completed a 120-item food-frequency questionnaire.
The average age of the women in this ancillary study was 58 years. Mean percentage weight loss was 10.7%. Completing more food journals was associated with a greater percentage of weight loss (interquartile range, 3.7% greater weight loss; P < .0001).
"For individuals who are trying to lose weight, the No. 1 piece of advice based on these study results would be to keep a food journal to help meet daily calorie goals" Dr. McTiernan said in the release. "It is difficult to make changes to your diet when you are not paying close attention to what you are eating."
Weight loss was less in women who skipped meals (4.3% lower weight loss; P < .05) and in those who ate out for lunch once a week or more (2.5% lower weight loss; P < .01). Eating out often at all meal times was associated with less weight loss, but the strongest association was observed with lunch.
"The mechanism is not completely clear, but we think that skipping meals or fasting might cause you to respond more favorably to high-calorie foods and therefore take in more calories overall," Dr. McTiernan said in the release. "We also think skipping meals might cluster together with other behaviors. For instance, the lack of time and effort spent on planning and preparing meals may lead a person to skip meals and/or eat out more."
To keep a food journal, participants were advised to:
Be honest and record everything consumed.
Be accurate by measuring portions and reading labels.
Be complete, including details of food preparation and any toppings or condiments added.
Be consistent, always carrying the food diary or using a smartphone diet-tracking application.
Limitations of this study include a reliance on self-report for weight loss-related behaviors and a lack of generalizability to populations other than predominantly non-Hispanic white, postmenopausal, overweight-to-obese women.
"We think our findings are promising because it shows that basic strategies such as maintaining food journals, eating out less often and eating at regular intervals are simple tools that postmenopausal women — a group commonly at greater risk for weight gain — can use to help them lose weight successfully," Dr. McTiernan concluded in the release.
The National Cancer Institute and the National Center for Research Resources supported this study. The study authors reported no potential conflict of interest.
J Academy Nutrition Dietetics. Published online July 13, 2012.
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