Predictors of dietary change among those who successfully lost weight in phase I of the Weight Loss Maintenance Trial.

Aim: Dietary changes occurring during weight loss interventions can vary. The present study tested if pretreatment psychosocial, dietary and demographic factors were associated with changes in fat intake and fruit and vegetable intake during a weight loss intervention.

Methods: This analysis includes participants who lost at least four kilograms during the initial six month weight loss phase (phase I) of the Weight Loss Maintenance Trial, a group format behavioural intervention emphasising a low-fat diet and increased physical activity. Multiple linear regression was used to determine associations between pretreatment psychosocial, dietary, physical activity, and demographic variables and changes from pretreatment to six months in fat intake and fruit and vegetable intake.

Results: Participants ( = 1032) were 63.4% female, 62.4% non-African American, and had a mean age of 55.6 and BMI of 34.1 kg/m. Being African American ( < 0.0001) and higher baseline kilojoule intake ( < 0.01) were associated with smaller reductions in fat intake. Being African American ( < 0.001) and older age ( = 0.02) were associated with smaller increases in fruit and vegetable intake, whereas a history of 10 or more past weight loss episodes of at least 10 lb (4.5 kg; < 0.01) was associated with greater increases.

Conclusions: Few psychosocial factors examined contributed to variability in dietary change. Even when achieving meaningful weight losses during a behavioural weight loss intervention, African Americans may make fewer beneficial changes in fat and fruit and vegetable intake than non-African Americans.