title: Higher nutritional quality at no additional cost among low-income households: insights from food purchases of "positive deviants".
abstract: BACKGROUND
  It is unknown whether diet quality is correlated with actual food expenditure. According to the positive deviance theory, the study of actual food expenditure by people with limited economic resources could help identify beneficial food-purchasing behavior.
  
  
  OBJECTIVE
  The aims were to investigate the relation between actual expenditure on food and nutritional quality and to identify "positive deviants" among low-income households.
  
  
  METHODS
  Individuals in deprived social situations (n = 91) were recruited as part of the "Opticourses" nutrition intervention conducted in 2012-2014 in poor districts of Marseille, France. Opticourses participants collected food-purchase receipts for their household over a 1-mo period. "Actual diet costs" and "estimated diet costs" were calculated per 2000 kcal of food purchases by using actual expenditures and a standard food price database of food consumed by a representative sample of French adults, respectively. Mean adequacy ratio (MAR), mean excess ratio (MER), and energy density (ED) were used as nutritional quality indicators. "Positive deviants" were defined as having a higher MAR and a lower MER than the respective median values.
  
  
  RESULTS
  Opticourses participants selected less-expensive food options than the average French population, both within a food group and for a given food item. Higher diet costs were associated with higher nutritional quality (higher MAR, lower ED), regardless of whether costs were calculated from actual expenditure or on the basis of standard food prices. Twenty-one positive deviants were identified. They made significantly healthier purchases than did other participants (MAR: +13%; MER: -90%. ED: -22%) at higher estimated diet costs. Yet, they did not spend more on food (having the same actual diet costs), which showed that they purchased food with a higher nutritional quality for their price.
  
  
  CONCLUSIONS
  In this low-income population, actual diet cost was positively correlated with nutritional quality, yet the results showed that higher diet quality is not necessarily more costly when foods with higher nutritional quality for their price are selected. The Opticourses intervention was registered at clinicaltrials.gov as NCT02383875.
authors.affiliation: Unité Mixte de Recherche (UMR) "Nutrition, Obesity and Risk of Thrombosis," Institut National de la Recherche Agronomique (INRA) 1260, Institut National de la Santé et de la Recherche Médicale (INSERM) 1062, University of Aix-Marseille, Marseille, France.
authors.forename: Lucile
authors.initials: L
authors.lastname: Marty
authors.affiliation: Unité Mixte de Recherche (UMR) "Nutrition, Obesity and Risk of Thrombosis," Institut National de la Recherche Agronomique (INRA) 1260, Institut National de la Santé et de la Recherche Médicale (INSERM) 1062, University of Aix-Marseille, Marseille, France.
authors.forename: Christophe
authors.initials: C
authors.lastname: Dubois
authors.affiliation: Unité Mixte de Recherche (UMR) "Nutrition, Obesity and Risk of Thrombosis," Institut National de la Recherche Agronomique (INRA) 1260, Institut National de la Santé et de la Recherche Médicale (INSERM) 1062, University of Aix-Marseille, Marseille, France.
authors.forename: Malu S
authors.initials: MS
authors.lastname: Gaubard
authors.affiliation: Unité Mixte de Recherche (UMR) "Nutrition, Obesity and Risk of Thrombosis," Institut National de la Recherche Agronomique (INRA) 1260, Institut National de la Santé et de la Recherche Médicale (INSERM) 1062, University of Aix-Marseille, Marseille, France.
authors.forename: Audrey
authors.initials: A
authors.lastname: Maidon
authors.affiliation: Unité Mixte de Recherche (UMR) "Nutrition, Obesity and Risk of Thrombosis," Institut National de la Recherche Agronomique (INRA) 1260, Institut National de la Santé et de la Recherche Médicale (INSERM) 1062, University of Aix-Marseille, Marseille, France.
authors.forename: Audrey
authors.initials: A
authors.lastname: Lesturgeon
authors.affiliation: Unité Mixte de Recherche (UMR) "Nutrition, Obesity and Risk of Thrombosis," Institut National de la Recherche Agronomique (INRA) 1260, Institut National de la Santé et de la Recherche Médicale (INSERM) 1062, University of Aix-Marseille, Marseille, France.
authors.forename: Hind
authors.initials: H
authors.lastname: Gaigi
authors.affiliation: Unité Mixte de Recherche (UMR) "Nutrition, Obesity and Risk of Thrombosis," Institut National de la Recherche Agronomique (INRA) 1260, Institut National de la Santé et de la Recherche Médicale (INSERM) 1062, University of Aix-Marseille, Marseille, France nicole.darmon@univ-amu.fr.
authors.forename: Nicole
authors.initials: N
authors.lastname: Darmon
mesh_terms: D000328:Adult; D002755:Choice Behavior; D003430:Cross-Sectional Studies; D004032:Diet / Q000191:economics* / Q000592:standards; D002149:Energy Intake; D005191:Family Characteristics; D005260:Female; D005502:Food / Q000191:economics*; D005518:Food Preferences; D058870:Food, Organic / Q000191:economics; D005602:France; D006801:Humans; D008297:Male; D008875:Middle Aged; D009753:Nutritive Value; D011203:Poverty
keywords: food expenditure; low income; nutrition economics; nutritional quality; positive deviance