Associations between the nutritional quality of snacks, overall diet quality and adiposity: findings from a nationally representative study of Australian adolescents

The primary aim of this study was to examine the association between snack nutritional quality, overall diet quality and adiposity among Australian adolescents. The secondary aim was to assess the distribution of discretionary foods (i.e. energy-dense and nutrient-poor foods and beverages) and intakes from the five food groups at different levels of snack nutritional quality. Dietary data collected from nationally representative adolescents (12–18 years old) during a 24-h dietary recall in the National Nutrition and Physical Activity Survey were analysed (n 784). Snacks were defined based on participant-identified eating occasions. Snack nutritional quality was assessed using the Nutrient Profiling Scoring Criterion (NPSC), whereas diet quality was evaluated using the Dietary Guideline Index for Children and Adolescents. Adiposity was assessed through BMI Z-score waist circumference and waist:height ratio (WHtR). Higher nutritional quality of snacks, as assessed by the NPSC, has been associated with higher diet quality among both boys and girls (P < 0·001). However, there is no association between snacks nutritional quality with BMI Z-score, waist circumference and WHtR. Among both boys and girls, the consumption of fruits, vegetables and legumes/beans at snacks increased with improvement in snack nutritional quality. Conversely, the consumption of discretionary foods at snack decreased with improvement in snack nutritional quality. In conclusion, improved snack quality was associated with better diet quality in adolescents. However, there was no association between snack nutritional quality and adiposity. Future, snack nutrition quality indices should consider optimum snack characteristics related with adiposity and diet quality.