Objective: To investigate the effect of an 8-week group-based cognitive behaviour therapy lifestyle intervention with monthly follow-up to 6 months and further follow up at 12 months on change in weight and other weight-related variables, change in physical activity and change in health and well being compared to individualised dietetic treatment or giving an information booklet only (BO).
Design: A randomised controlled trial of two intervention groups, a group-based cognitive behaviour therapy lifestyle intervention, Fat Booters Incorporated--(FBI) and individualised dietetic treatment (IDT) and control group receiving an information booklet only (BO). The intervention groups involved weekly contact for 8 weeks with monthly follow-up to 6 months and further follow-up at 12 months, conducted in real practice setting.
Subjects: A total of 176 adults with body mass index (BMI)>27 kg/m2, mean (+/-s.d.) age 48+/-13 years, mean BMI 34+/-5.5 kg/m2.
Main outcome measures: Weight, percent body fat, waist circumference, physical activity, health status, self-efficacy and satisfaction with life were measured at baseline, 3, 6 and 12 months.
Results: A statistically significant difference between groups was observed for weight change over time (P=0.05). The change in weight (mean+/-s.e.) for the FBI group was significantly greater than the BO group at 3 and 12 months (-2.8+/-0.7 compared to -1.0+/-0.6 kg, P<0.05 and -2.9+/-0.9 compared to +0.5+/-0.9 kg, P<0.005, respectively). Change in weight in the IDT group did not differ from the FBI group at any time point. For all groups, waist circumference was significantly less than baseline at all time points (P<0.001). Significant differences in self-efficacy were observed over time (P=0.02), with both intervention groups having greater self-efficacy than the BO group. Significant drop-outs occurred over time for all three groups.
Conclusions: A cognitive behaviour-based lifestyle intervention was more effective than providing an information booklet alone and as effective as intensive individualised dietetic intervention in weight loss and improvements in self-efficacy.