Everyone knows that eating a low-fat, low-calorie diet and getting regular exercise helps shed pounds, but a new study led by Hutchinson Center researchers has found that when it comes to losing weight and body fat, diet and exercise are most effective when done together as compared to either strategy alone.
The results of this randomized trial, led by the Public Health Sciences Division’s Dr. Anne McTiernan, were published online April 14 in Obesity.
The majority of women in the study who both improved their diet and exercised regularly shed an average of nearly 11 percent of their starting weight, which exceeded the study’s goal of a 10 percent or more reduction in body weight.
“We were surprised at how successful the women were,” McTiernan said. “Even though this degree of weight loss may not bring an obese individual to a normal weight, losing even this modest amount of weight can bring health benefits such as a reduced risk of diabetes, heart disease and cancer.”
The yearlong intervention involved 439 overweight-to-obese, sedentary, postmenopausal Seattle-area women, ages 50 to 75, who were randomly assigned to one of four groups:
“Although numerous studies have examined the effect of lifestyle interventions on weight, few have focused on postmenopausal women, a group that experiences particularly high rates of overweight and obesity,” McTiernan said.
Weight-loss percentages per group
At the end of the intervention, the researchers found:
Body-mass index (height-to-weight ratio), waist circumference and percentage of body fat were also significantly reduced among the three intervention groups. The women who were assigned to the nonintervention control group, who did not change their diet or activity level, on average lost less than a pound—a statistically insignificant decrease.
Strategies associated with the most successful weight loss included:
The combined diet-plus-exercise arm of the study followed the current nutrition and physical activity recommendations by the National Institutes of Health Obesity Education Initiative Expert Panel.
Factoring psychological, behavioral barriers to weight loss
Despite the overwhelming evidence for the benefits of lifestyle-induced weight loss, there are still major barriers to implementing these programs, the authors wrote. To this end, McTiernan and colleagues are conducting ongoing follow up of these study participants to try to determine factors—both psychological and behavioral—that are associated with long-term maintenance of weight loss.
|Weight loss study needs Seattle-area women 50 and over
Seattle-area women who are 50 to 75 and overweight may qualify to participate in a Hutchinson Center study that is evaluating the effectiveness of vitamin D on weight loss and breast cancer prevention.
Visit the ViDA Web page for more information.
“Identifying factors that help women not only lose weight but keep it off long term will help steer the development and implementation of obesity-treatment programs that have the greatest promise to impact public health,” she said.
The National Cancer Institute funded the research. PHS co-authors include Liren Xiao, Carolyn Bain, and Drs. Catherine Duggan and Chin-Yung Wang, as well as investigators from the University of Washington School of Medicine, the NCI Office of Cancer Survivorship, the University of British Columbia and Harvard Medical School.