Purchase of core food groups among food-insecure families: secondary analysis of the Spend Study

Environmental, behavioural, and personal factors all influence food choices. A lack of income is one major reason for the purchase of foods that do not conform to dietary guideline recommendations; however limited research has been conducted investigating the efficacy of providing additional money to low income groups to see the impact this has on food purchasing. This thesis has two parts: a descriptive study using baseline data from the Spend Study and an intervention study. The aims of the descriptive study were firstly to examine differences in food purchases (in relation to gram amounts and brand types) for low-income households with children by income (very low income (< $30,000) compared to low income ($30,000 to $45,000)), food security status (low food security compared to moderate food security), and level of education (no secondary school qualification compared to secondary school or post-secondary school qualification(s)). A further aim was to examine whether expenditure on fruit and vegetables was adequate to meet “5+ a day” recommendations. The aims of the second part of this thesis (the intervention study) were to investigate whether the grams of food purchased per week changed with provision of supermarket vouchers and also to investigate the participant perceived impact of the additional money on food purchases. The Spend Study was a parallel randomised controlled trial, involving food shopping receipt collection over an eight week period (a four week baseline phase followed by a four week intervention phase), conducted in Dunedin, New Zealand. Low-income, food-insecure households with at least one child less than 18 years of age were recruited. Participants were randomised to either an intervention group which received vouchers (n=82) or a control group which did not receive any vouchers until the end of the study (n=71). Analyses of the baseline data (n=165) showed those with a higher income purchased significantly more grams of fruit per week, and those with a higher food security status purchased significantly more grams of vegetables per week. Higher educational attainment was associated with increased purchase of fruit and vegetables. Households needed to spend an additional $2.76 per day on fruit and vegetables to meet “5+ a day” recommendations. Provision of additional money did not have an effect on gram amounts or type of fruit and vegetables purchased (fresh compared to canned, dried, or frozen), but participants did note additional money relieved stress or enabled a wider variety of foods to be purchased. Results showed food purchase decisions are altered by household demographics such as income, education, and food security status