Oral Presentation Australian & New Zealand Obesity Society 2015 Annual Scientific Meeting

A process evaluation of the supermarket healthy eating for life randomized controlled trial (#50)

Dana Lee Olstad 1 , Kylie Ball 1 , Gavin Abbott 1 , Sarah McNaughton 1 , Ha ND Le 2 , Cliona Ni Mhurchu 3 , Christina Pollard 4 , David Crawford 1
  1. Centre for Physical Activity and Nutrition Research, Deakin University, Burwood, VIC, Australia
  2. Deakin Health Economics, Deakin University, Burwood, VIC, Australia
  3. National Institute for Health Innovation, School of Population Health, University of Auckland, Auckland, New Zealand
  4. School of Public Health, Curtin University, Perth, Western Australia, Australia

Background: Supermarket Healthy Eating for Life (SHELf) was a randomized controlled trial that tested the impact of individual (skill-building), environmental (20% price reductions), and combined (skill-building + 20% price reductions) interventions on women’s purchasing and consumption of fruits, vegetables, and healthier beverages.  This process evaluation investigated the reach, effectiveness, implementation and maintenance of the SHELf interventions.

Methods: RE-AIM provided a framework to examine processes underlying intervention impact using data from participant surveys and objective sales data collected at baseline, post-intervention (3 months) and 6-months post-intervention. Fisher’s exact and χ2 tests assessed differences in quantitative survey responses among groups. Adjusted linear regression examined the impact of self-reported intervention dose on food purchasing and consumption outcomes.  Thematic analysis identified key themes within qualitative responses. 

Results: Reach of the SHELf interventions to disadvantaged groups, and beyond study participants themselves, was moderate.  Just over one-third of intervention participants indicated the interventions were effective in changing the way they bought, cooked or consumed food (p<0.001 compared to control), with no differences among intervention groups. Improvements in purchasing and consumption outcomes were greatest among those who received a higher intervention dose. Most notably, participants who said they accessed price reductions on fruits and vegetables purchased (519 g/week) and consumed (0.5 servings/day) more vegetables.  Most participants said they accessed (82%) and appreciated discounts on fruits and vegetables, while there was limited use (40%) and appreciation of discounts on healthier beverages. Overall reported satisfaction with, use of, and impact of the skill-building resources was moderate. Maintenance of newly acquired behaviours was limited, with less than half of participants making changes or using study-provided resources during the 6-month post-intervention period.  

Conclusions: SHELf’s reach and perceived effectiveness were moderate, and the effectiveness of the interventions depended on the dose received (i.e. implementation).  Maintenance of newly acquired behaviours proved challenging.