Dice, Golf Balls, and CDs: Assumptions About Portion Size Measurement Aids

Purpose: Portion size measurement aids (PSMAs) are used extensively by dietitians. In this cross-sectional, descriptive study, we explored the degree of consistency and concordance between measured and putative volumes of selected household and sport-related PSMAs that are commonly used for nutrition education and dietary assessment. Methods: An online search of portion size resources yielded several governmental and academic descriptions of household PMSAs (e.g., a compact disc, a nine-volt battery) and sportrelated PMSAs (e.g., a golf ball) and their purported dimensions. The spherical items were purchased locally and measured using electronic digital calipers; measurements were then converted to volumes, in millilitres. Results: Overall, we observed a high degree of heterogeneity in how different educational resources related sport-related PSMAs to portion sizes of food. The mean percentage of error between the measured and putative volumes of PSMAs varied considerably. Conclusions: Our findings indica...