Abstract
Objectives. The objectives of this pilot study were to compare the dietary, physiological and metabolic effects of 12-week modified carbohydrate nutrition intervention when disseminated in an individualized home-based format versus a group classroom-based format. Methods. Twenty-three overweight (≥85th percentile BMI) Latina adolescent females (12–17 years of age) were randomized to a 12-week modified carbohydrate dietary intervention delivered in either an individualized home-based format (n = 11) or a group classroom-based format (n = 12). Anthropometrics, dietary intake by 3-day diet records, insulin dynamics by extended 3-hour Oral Glucose Tolerance test (OGTT) and body composition by Dual energy X-ray absorptiometry (DXA) were measured before and after intervention; 24-hour diet recalls were collected once or twice per month throughout the program. Results. Mixed modeling showed no significant differences in changes in dietary intake between intervention groups, but both groups significantly reduced intake of added sugar, sugary beverages and refined carbohydrates by 33%, 66%, and 35%, respectively, and dietary fiber significantly increased by 44% (p <0.01) throughout the 12 weeks. There was a significant time effect for BMI z-scores within each intervention group (p <0.05). There was no significant time*intervention group interaction for any of the physiological or metabolic variables, indicating that change over time was not significantly different between intervention groups. Conclusions. Although a culturally tailored, modified carbohydrate dietary intervention led to significant improvements in dietary intake and BMI z-scores, the extremely intensive, individualized, home-based program was no more effective at improving diet, decreasing adiposity or reducing type 2 diabetes risk factors than the traditional classroom-based format.
This study was supported by the Dr. Robert C. Atkins Foundation, the General Clinic Research Center (National Center for Research Resources Grant MO1 RR 00043), and the American Diabetes Association, Mentor-Based Postdoctoral Fellowship 2005 (awarded to M.I.G.). We are grateful to the nurses and nutrition staff at the USC-GCRC. Finally, we express our gratitude to the children and their families for making this study possible.