title: Energy density, energy costs and income - how are they related?
abstract: OBJECTIVE
  To examine the association between energy density and energy costs in single food items and composed diets, and to explore differences in energy density and energy cost between income levels.
  
  
  METHODS
  A cross-sectional study using data from two Dutch cohort studies and recent national food prices. Food prices were retrieved from two market leader supermarkets. Data on dietary intake were measured using a computerized face-to-face interview (cohort 1) and 24 h recalls (cohort 2).
  
  
  METHODS
  The Netherlands.
  
  
  METHODS
  A sample of 373 young adults from the Amsterdam Growth and Health Longitudinal Study (AGHLS, measured in 2000) and a sample of 200 community-dwelling elderly from the Longitudinal Ageing Study Amsterdam (LASA, measured in 2007).
  
  
  RESULTS
  We found significant inverse associations between energy density and energy costs in single food items (r = -0.436, P < 0.01) and composed diets (AGHLS men r = -0.505, women r = -0.413, P < 0.001; LASA men r = -0.559, women r = -0.562, P < 0.001). Furthermore, we found that people stratified into higher energy density quartiles consumed significantly more energy per day, less fruits and vegetables, and had significantly lower diet costs. Explorative analyses on income did not reveal significant differences regarding energy density, costs, or fruit and vegetable intake.
  
  
  CONCLUSIONS
  In the Netherlands also, energy density was inversely related with energy costs, implying that healthier diets cost more. However, we could not find differences in energy density or costs between income levels. Future research, using precise food expenditures, is of main importance in studying the economics of obesity and in the aim of making the healthier choice easier.
authors.affiliation: Department of Health Sciences and the EMGO Institute for Health and Care Research, Faculty of Earth and Life Sciences, VU University Amsterdam, De Boelelaan 1085, 1081 HV Amsterdam, The Netherlands. wilma.waterlander@falw.vu.nl
authors.forename: Wilma E
authors.initials: WE
authors.lastname: Waterlander
authors.forename: Wendy E
authors.initials: WE
authors.lastname: de Haas
authors.forename: Inge
authors.initials: I
authors.lastname: van Amstel
authors.forename: Albertine J
authors.initials: AJ
authors.lastname: Schuit
authors.forename: Jos W R
authors.initials: JW
authors.lastname: Twisk
authors.forename: Marjolein
authors.initials: M
authors.lastname: Visser
authors.forename: Jacob C
authors.initials: JC
authors.lastname: Seidell
authors.forename: Ingrid H M
authors.initials: IH
authors.lastname: Steenhuis
mesh_terms: D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003430:Cross-Sectional Studies; D004032:Diet / Q000191:economics*; D002149:Energy Intake; D005260:Female; D005502:Food / Q000191:economics*; D006801:Humans; D007182:Income; D008137:Longitudinal Studies; D008297:Male; D008875:Middle Aged; D009426:Netherlands; D011203:Poverty; D012737:Sex Factors