Age differences in the use of serving size information on food labels: numeracy or attention?

Abstract

Objective: The ability to use serving size information on food labels is important for managing age-related chronic conditions such as diabetes, obesity and cancer. Past research suggests that older adults are at risk for failing to accurately use this portion of the food label due to numeracy skills. However, the extent to which older adults pay attention to serving size information on packages is unclear. We compared the effects of numeracy and attention on age differences in accurate use of serving size information while individuals evaluated product healthfulness.

Design: Accuracy and attention were assessed across two tasks in which participants compared nutrition labels of two products to determine which was more healthful if they were to consume the entire package. Participants' eye movements were monitored as a measure of attention while they compared two products presented side-by-side on a computer screen. Numeracy as well as food label habits and nutrition knowledge were assessed using questionnaires.

Setting: Sacramento area, California, USA, 2013-2014.

Subjects: Stratified sample of 358 adults, aged 20-78 years.

Results: Accuracy declined with age among those older adults who paid less attention to serving size information. Although numeracy, nutrition knowledge and self-reported food label use supported accuracy, these factors did not influence age differences in accuracy.

Conclusions: The data suggest that older adults are less accurate than younger adults in their use of serving size information. Age differences appear to be more related to lack of attention to serving size information than to numeracy skills.

Keywords: Food choice; Healthier choices; Nutrition label use; Serving size information.

Fig. 1

(colour online) Sample comparisons for inconsistent (top; per-serving and per-container information are inconsistent, so requires servings-per-container information for correct answer) and consistent (bottom; per-serving and per-container information are consistent with each other, so does not require servings-per-container information) trials

Fig. 2

(colour online) Predicted values from attention model in Table 5 showing the association between age and accuracy for high and low levels of attention and numeracy (, low attention, low numeracy; , low attention, high numeracy; , high attention, low numeracy; , high attention, high numeracy) in Task 1 (top row) and Task 2 (bottom row), for consistent (left column) v. inconsistent trials (right column). Nutrition knowledge and income are set at high and median levels, respectively