The impact of financial incentives on participants’ food purchasing patterns in a supermarket-based randomized controlled trial
Abstract Background The impacts of supermarket-based nutrition promotion interventions might be overestimated if participants shift their proportionate food purchasing away from their usual stores. This study quantified whether participants who received price discounts on fruits and vegetables (FV)...
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| Format: | Article |
| Language: | English |
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BMC
2017-08-01
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| Series: | International Journal of Behavioral Nutrition and Physical Activity |
| Subjects: | |
| Online Access: | http://link.springer.com/article/10.1186/s12966-017-0573-0 |
| _version_ | 1818011288942411776 |
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| author | Dana Lee Olstad David A Crawford Gavin Abbott Sarah A McNaughton Ha ND Le Cliona Ni Mhurchu Christina Pollard Kylie Ball |
| author_facet | Dana Lee Olstad David A Crawford Gavin Abbott Sarah A McNaughton Ha ND Le Cliona Ni Mhurchu Christina Pollard Kylie Ball |
| author_sort | Dana Lee Olstad |
| collection | DOAJ |
| description | Abstract Background The impacts of supermarket-based nutrition promotion interventions might be overestimated if participants shift their proportionate food purchasing away from their usual stores. This study quantified whether participants who received price discounts on fruits and vegetables (FV) in the Supermarket Healthy Eating for Life (SHELf) randomized controlled trial (RCT) shifted their FV purchasing into study supermarkets during the intervention period. Methods Participants were 642 females randomly assigned to a 1) skill-building (n = 160), 2) price reduction (n = 161), 3) combined skill-building and price reduction (n = 160), or 4) control (n = 161) group. Participants self-reported the proportion of FV purchased in study supermarkets at baseline, 3- and 6-months post-intervention. Fisher’s exact and χ2 tests assessed differences among groups in the proportion of FV purchased in study supermarkets at each time point. Multinomial logistic regression assessed differences among groups in the change in proportionate FV purchasing over time. Results Post-intervention, 49% of participants purchased ≥50% of their FV in study supermarkets. Compared to all other groups, the price reduction group was approximately twice as likely (RRR: 1.8-2.2) to have increased proportionate purchasing of FV in study supermarkets from baseline to post-intervention (p< 0.05). Conclusions Participants who received price reductions on FV were approximately twice as likely to shift their FV purchasing from other stores into study supermarkets during the intervention period. Unless food purchasing data are available for all sources, differential changes in purchasing patterns can make it difficult to discern the true impacts of nutrition interventions. Trial registration The SHELf trial is registered with Current Controlled Trials Registration ISRCTN39432901, Registered 30 June 2010, Retrospectively registered ( http://www.isrctn.com/ISRCTN39432901 ). |
| first_indexed | 2024-04-14T06:05:56Z |
| format | Article |
| id | doaj.art-abb449feebb44e6280582b79ca8eabda |
| institution | Directory Open Access Journal |
| issn | 1479-5868 |
| language | English |
| last_indexed | 2024-04-14T06:05:56Z |
| publishDate | 2017-08-01 |
| publisher | BMC |
| record_format | Article |
| series | International Journal of Behavioral Nutrition and Physical Activity |
| spelling | doaj.art-abb449feebb44e6280582b79ca8eabda2022-12-22T02:08:32ZengBMCInternational Journal of Behavioral Nutrition and Physical Activity1479-58682017-08-011411710.1186/s12966-017-0573-0The impact of financial incentives on participants’ food purchasing patterns in a supermarket-based randomized controlled trialDana Lee Olstad0David A Crawford1Gavin Abbott2Sarah A McNaughton3Ha ND Le4Cliona Ni Mhurchu5Christina Pollard6Kylie Ball7Department of Community Health Sciences, University of CalgaryDeakin University, Geelong, Australia, Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition SciencesDeakin University, Geelong, Australia, Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition SciencesDeakin University, Geelong, Australia, Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition SciencesDeakin University, Geelong, Australia, Deakin Health EconomicsNational Institute for Health Innovation, School of Population Health, The University of AucklandSchool of Public Health, Faculty of Sciences, Curtin UniversityDeakin University, Geelong, Australia, Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition SciencesAbstract Background The impacts of supermarket-based nutrition promotion interventions might be overestimated if participants shift their proportionate food purchasing away from their usual stores. This study quantified whether participants who received price discounts on fruits and vegetables (FV) in the Supermarket Healthy Eating for Life (SHELf) randomized controlled trial (RCT) shifted their FV purchasing into study supermarkets during the intervention period. Methods Participants were 642 females randomly assigned to a 1) skill-building (n = 160), 2) price reduction (n = 161), 3) combined skill-building and price reduction (n = 160), or 4) control (n = 161) group. Participants self-reported the proportion of FV purchased in study supermarkets at baseline, 3- and 6-months post-intervention. Fisher’s exact and χ2 tests assessed differences among groups in the proportion of FV purchased in study supermarkets at each time point. Multinomial logistic regression assessed differences among groups in the change in proportionate FV purchasing over time. Results Post-intervention, 49% of participants purchased ≥50% of their FV in study supermarkets. Compared to all other groups, the price reduction group was approximately twice as likely (RRR: 1.8-2.2) to have increased proportionate purchasing of FV in study supermarkets from baseline to post-intervention (p< 0.05). Conclusions Participants who received price reductions on FV were approximately twice as likely to shift their FV purchasing from other stores into study supermarkets during the intervention period. Unless food purchasing data are available for all sources, differential changes in purchasing patterns can make it difficult to discern the true impacts of nutrition interventions. Trial registration The SHELf trial is registered with Current Controlled Trials Registration ISRCTN39432901, Registered 30 June 2010, Retrospectively registered ( http://www.isrctn.com/ISRCTN39432901 ).http://link.springer.com/article/10.1186/s12966-017-0573-0SupermarketFood purchasingFruits and vegetablesPrice reductionsRandomized controlled trial |
| spellingShingle | Dana Lee Olstad David A Crawford Gavin Abbott Sarah A McNaughton Ha ND Le Cliona Ni Mhurchu Christina Pollard Kylie Ball The impact of financial incentives on participants’ food purchasing patterns in a supermarket-based randomized controlled trial International Journal of Behavioral Nutrition and Physical Activity Supermarket Food purchasing Fruits and vegetables Price reductions Randomized controlled trial |
| title | The impact of financial incentives on participants’ food purchasing patterns in a supermarket-based randomized controlled trial |
| title_full | The impact of financial incentives on participants’ food purchasing patterns in a supermarket-based randomized controlled trial |
| title_fullStr | The impact of financial incentives on participants’ food purchasing patterns in a supermarket-based randomized controlled trial |
| title_full_unstemmed | The impact of financial incentives on participants’ food purchasing patterns in a supermarket-based randomized controlled trial |
| title_short | The impact of financial incentives on participants’ food purchasing patterns in a supermarket-based randomized controlled trial |
| title_sort | impact of financial incentives on participants food purchasing patterns in a supermarket based randomized controlled trial |
| topic | Supermarket Food purchasing Fruits and vegetables Price reductions Randomized controlled trial |
| url | http://link.springer.com/article/10.1186/s12966-017-0573-0 |
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