Size Matters: Package Size Influences Recognition of Serving Size Information.

PURPOSE: To identify the impact of package size on an individual's use of serving size information. The hypothesis was that participants would make more serving size assumption errors on a nutrition facts table (NFT) interpretation task when assessing packages that appear as a single serving but contain multiple servings, compared with products that appear as a multi-serving and contain multiple servings.

METHODS: Sixty participants were randomized into 1 of 3 conditions (n = 20 each); products that appeared as a single serving and contain a single serving (SSSS), products that appeared as a single serving and contain multiple servings (SSMS), and products that both appear as a multi-serving and contain multiple servings (MSMS). All 3 conditions were tested on a NFT interpretation task while participants were being presented food items that were appropriate to their given condition.

RESULTS: Participants in the SSMS (9.55 ± 7.78) condition made significantly more serving size assumption errors than the SSSS (0.00 ± 0.00; P < 0.001) and MSMS (0.40 ± 0.75; P < 0.001) conditions.

CONCLUSIONS: Participants did not address serving size information when they perceived a product to be a single serving. This resulted in people misinterpreting nutritional and caloric content of foods that were single unit foods with multiple servings.