Focus on portion size in weight managementthe development and evaluation of the Smartsize program
Large portions lead to increased energy intake and are seen as a key factor in the development of obesity. The aim of this research was to develop and evaluate.a weight management program focused on serving sizes.
Overweight and obesity adults were included in a randomized controlled study (intervention group n = 139, control group n = 139). The intervention group received the SMART-size program for three months. Participants in the control group received no intervention. Outcome measures were BMI and self-reported use of portion control strategies to keep grip on portions, measured at baseline and after three, six and twelve months.
The intervention group showed a decline in BMI of 0.45 (95% CI =-0.04 to-0.88) compared to the control group. Their average use of the portion control strategies increased compared to the control group (B = 0.33, 95% CI 0.23-0.43) and also the percentage of intensively used strategies (B = 10.7%, 95% CI 6.9-14.4%). The difference in weight loss between the two groups almost disappeared after six months (B =-0.13, 95% CI 0.67 to-0.37) and twelve months (B =-0.03, 95% CI-0.53 to 0.47).
The intervention is effective to initiate weight loss. However, more research is needed into the effectiveness of a more extensive program on long term weight loss. For example by adding more relapse prevention strategies, to extend the intervention duration or embedding the intervention into the diet treatment.