Diet cost, diet quality and socio-economic position: how are they related and what contributes to differences in diet costs?

OBJECTIVE: To examine diet costs in relation to dietary quality and socio-economic position, and to investigate underlying reasons for differences in diet costs.
DESIGN: Dietary intake was assessed by a 4 d food diary and evaluated using the 2005 Healthy Eating Index (HEI). National consumer food prices collected by Statistics Sweden and from two online stores/supermarkets were used to estimate diet costs.
SETTING: Sweden.
SUBJECTS: A nationally representative sample of 2160 children aged 4, 8 or 11 years.
RESULTS: Higher scores on the HEI resulted in higher diet costs and, conversely, higher diet costs were linked to increased total HEI scores. Children who consumed the most healthy and/or expensive diets ate a more energy-dilute and varied diet compared with those who ate the least healthy and/or least expensive diets. They also consumed more fish, ready meals and fruit. Regression analysis also linked increased food costs to these food groups. There was a positive, but weak, relationship between HEI score and diet cost, parental education and parental occupation respectively.
CONCLUSIONS: Healthy eating is associated with higher diet cost in Swedish children, in part because of price differences between healthy and less-healthy foods. The cheapest and most unhealthy diets were found among those children whose parents were the least educated and had manual, low-skill occupations. Our results pose several challenges for public health policy makers, as well as for nutrition professionals, when forming dietary strategies and providing advice for macro- and microlevels in society.