Dieting Study Highlights Benefits of Group Support

Dieters who have the help of a support group may experience less stress and less of a brainpower drain than those who go it alone, results of a study by Agricultural Research Service (ARS) nutrition scientists and their ARS-funded colleagues suggest.

The investigation apparently is the first to concurrently examine the interplay between several factors that had figured in earlier weight-loss research: supervised versus unsupervised dieting; increased stress; and an early, temporary decrease in mental performance. That's according to Molly Kretsch, a national program leader for ARS' human nutrition research, and a coinvestigator on the study. She's based in Beltsville, Md.

Fifty-six healthy, overweight women aged 23 to 45 completed the study, participating for eight weeks in either supervised or unsupervised weight-loss regimens or in a grouping that neither dieted nor met as a group.

Dieters who attended weekly support-group sessions did not have a significant increase in cortisol, a stress-associated hormone, at the end of the study's first week, but the unaided dieters did. What's more, at that same checkpoint, the unassisted dieters scored lower in two computerized tests of their working-memory capacity--one aspect of mental performance--than did the supervised and the nondieting volunteers.

One test, for example, required volunteers to remember numbers that appeared only briefly on the computer screen.

Even though there were no significant differences among volunteers' mental performance scores by the four- and eight-week checkpoints, the differences noted at the end of the first week nonetheless interest researchers and healthcare professionals who want to help dieters reduce weight-loss-associated stress and mental performance problems. Either or both kinds of problems--and the earliness with which they occur during dieting--may lead dieters to quit their weight-loss programs too soon.

Prospective dieters might include any of the millions of adult Americans who are overweight or obese.

Kretsch and neuroscience researchers Michael W. Green and Nicola A. Elliman of Aston University, Birmingham. U.K., reported their findings in a 2005 issue of the journal Psychoneuroendocrinology.

ARS is the U.S. Department of Agriculture's chief scientific research agency.