Psychological and Behavioral Predictors of Short-Term and Long-Term Weight Loss in a Diabetes Lifestyle Intervention

Understanding the effect lifestyle intervention (LI) has on psychological and behavioral factors that are associated with weight loss can help inform LI design, content, and delivery.

The aim was to determine the modifiable psychological and behavioral factors associated with percent weight loss and their relative importance in predicting percent weight loss at 1-year and 4-year follow-up.

This is a secondary analysis of prospectively collected data in Look AHEAD (Action for Health in Diabetes) LI participants using validated self-administered questionnaires to measure variables.

Adults with type 2 diabetes and overweight/obesity were recruited from 6 Look AHEAD clinical sites in the United States. In total, 365 participants were included in the analysis of 1-year weight loss (9% attrition), and 349 participants were included in the analysis of 4-year weight loss (13% attrition; data were collected from September 2002 to May 2008).

The LI included 3 group sessions and 1 individual session per month in the first 6 months and 2 group sessions and 1 individual session per month in months 7 to 12.

The primary outcomes were percent weight loss at 1-year and 4-year follow-up.

Baseline and 6-month change scores in psychological and behavioral variables were modeled as predictors of percent weight loss at 1-year and 4-year follow-up using stepwise linear and least absolute shrinkage and selection operator regression. Random forests were used to compare the relative importance of variables in predicting percent weight loss.

Six-month improvements in diet self-efficacy, readiness to limit high-fat foods, diet self-regulation, low-fat, healthy eating behaviors, and reductions in perceived stress and binge eating frequency were positive predictors of 1-year weight loss. Six-month improvements in diet self-efficacy and low-fat, low-calorie healthy eating behaviors persisted as independent modifiable predictors of greater 4-year weight loss.

Look AHEAD's LI resulted in 6-month improvements in modifiable psychological and behavioral factors that were associated with percent weight loss at 1-year and 4-year follow-up. LI programs for weight loss should focus on skills and strategies to promote diet self-efficacy, readiness to change, diet self-regulation, stress and binge eating management, and habituation of low-fat eating habits during the intervention period.