Nutrient and core and non-core food intake of Australian schoolchildren differs on school days compared to non-school days

Highlights

• The diets of schoolchildren are of lower nutritional quality on non-school days.

• Intakes of total fat, saturated fat and sugars are higher.

• Children are more likely to consume non-essential foods.

Abstract

Overall the diets of Australian schoolchildren are suboptimal, but differences in nutrient and food intake on school versus non-school days have not been assessed. The aim of this study was to examine differences in nutrient and core and non-core food intake on school days versus non-school days in Australian schoolchildren aged 6–16 years. Cross-sectional analysis of the 2007 Australian Children's Nutrition and Physical Activity Survey. Dietary intake was assessed via one 24-h dietary recall. A school day was defined as Monday–Friday, a non-school day included Saturday, Sunday and public/school holidays. Independent t-tests and χ² tests were used to assess differences in continuous and categorical variables, respectively. Multiple linear and logistic regression was used to adjust for confounders. Forty-eight per cent of recalls were completed on a non-school day. On non-school days primary schoolchildren aged 6–11 years (n = 1334) and secondary schoolchildren aged 12–16 years (n = 1362) had significantly higher absolute intakes of sugars, total fat and saturated fat (all P < 0.05). In addition the energy density of foods consumed was greater (P < 0.001), but there was no difference in the energy density of fluids. The sodium density of the diet did not differ across day types. On non-school days, total core food intake was ~30% higher and children were more likely to consume sugar-sweetened beverages, fried potatoes and take-away pizzas and burgers (all P < 0.05). Important differences in the intake of sugar, total fat, and saturated fat and noncore foods exist on non-school days compared to school days in Australian schoolchildren. To improve the diets of schoolchildren there is scope for strategies that target non-school day eating practices.

Introduction

Globally childhood overweight and obesity are a major public health concern (Wang & Lobstein, 2006). In Australia in 2011–2012 among children aged 5–17 years, 18.3% were overweight and 7.4% were obese (Australian Bureau of Statistics, 2013). Whilst the causes of excess weight gain during childhood are multi-faceted and complex (Karnik & Kanekar, 2012), dietary intake is considered an important modifiable factor to help reduce childhood obesity risk (World Health Organization, 2012). Poor quality, energy dense diets, characterised by high levels of fat and sugar (Swinburn, Caterson, Seidell, & James, 2004), along with high sodium intakes (Grimes et al, 2013b, Grimes et al, 2013, He et al, 2008), have been associated with adiposity in children. Findings from the 2007 Australian National Children's Nutrition and Physical Activity Survey (CNPAS) indicate overall suboptimal dietary intakes of Australian children and adolescents where approximately 80% of children exceeded the dietary recommendations for saturated fat (i.e. <10% energy from saturated fat), 30–40% exceeded recommendations for sugar (i.e. <20% energy from total sugars) and all children exceeded recommended intakes for sodium (Department of Health and Ageing, Australian Food and Grocery Council, & Department of Agriculture Fisheries and Forestry, 2008). In addition to the overall poor nutrient profile of Australian children's diets, intake of ‘extra’ foods, also referred to as ‘non-core’ (National Health and Medical Research Council, 2013a) (high in energy, saturated fat, and/or added sugars or salt) have been shown to be an important source of energy, contributing to 35% of daily energy intake in children aged 2–16 years (Rangan, Randall, Hector, Gill, & Webb, 2008). In addition, the consumption of these foods may displace more nutrient dense foods (National Health and Medical Research Council, 2013a).

To identify opportunities for intervention to improve the quality of children's diets it is important to understand how children's dietary behaviours and intake may vary in different settings. Internationally, there is some evidence to suggest that the quality of children's diets may differ on school days compared to weekends and holiday periods (Rockell et al, 2011, Rothausen et al, 2012). For example in a nationally representative sample of Danish children aged 7–14 years it was found that non-school day diets were more energy dense and higher in added sugars and lower in fibre (Rothausen et al., 2012). Foods that contributed to the overall poorer nutrient profile of children's diets on non-school days included greater consumption of sugar-sweetened beverages (SSBs) and sweet products and reduced consumption of fruits and vegetables (Rothausen et al., 2012). In a large national sample of New Zealand children aged 5–14 years fewer differences in nutrient intake across school days and non-school days were observed, but increased consumption of SSBs, hot chips and reduced intakes of fruit and vegetables were reported (Rockell et al., 2011). Conversely, in a national sample of US children aged 6–18 years there was no difference in intakes of energy, fat or carbohydrate (Haines, Hama, Guilkey, & Popkin, 2003).

Currently it is unknown if nutrient and food intake differs on school days compared to non-school days in Australian schoolchildren. This information can be used to inform targeted healthy eating strategies for the school and home environment. The aim of this study was to examine differences in nutrient intake and core and non-core food intake on school days versus non-school days in a nationally representative sample of Australian schoolchildren aged 6–16 years.