Does colour variety accurately quantify nutritional value in children's lunchboxes? A pilot study

In advocating a diet rich in fruit and vegetables, public health authorities emphasise dietary colour variety to ensure adequate nutrient consumption. The relationship between food colour variety and nutritional value in children's lunches attending one school was evaluated.

Observational cross-sectional study.

Eighty-two children had their lunchboxes photographed over one day. Foods were scored using the Nutri-score labelling system, assigning foods a letter based on nutritional content. Composite Nutri-scores were calculated as average total Nutri-score per food per lunchbox. Eleven observers used a colour chart to assign colours to foods from a sample of lunchboxes; intra-class correlation was calculated. Associations between nutrient scores and colour variety were estimated.

Lunchboxes contained an average of 4 ± 1 colours. Number of colours did not vary by age or sex. Two thirds of lunches had composite Nutri-scores of C or better, with better scores in older children. There was no association between colour variety and composite Nutri-score. Fruit, vegetables, whole grains and fats were associated with greater colour variety. Vegetables and meat, fish and eggs were associated with better scores; refined grains, dairy, snacks, fats and condiments were associated with worse.

Although this study did not demonstrate a relationship between colour variety and nutritional score, findings suggest that lunches containing fruit and vegetables tended towards greater colour variety than those without. This indicates that adjusting guidelines to incorporate food colour variety may be of use in future iterations of dietary guidelines for children.