2018 Volume 6 Issue 1 Pages 60-69
Objective To standardize the dietary assessment, we review the conversion factor between food volume and weight (mass density [MD]). MDs are not currently listed in the Japanese Standard Food Composition Table (FCT).
Methods The FCTs in the U.S. and New Zealand were observed to search for the foods/dishes indicating the nutrient composition per volume and calculate MD (g/cm3). The units of volume were cup, fl oz, tablespoon, teaspoon, and mL.
Results The calculation of MD was possible in 3,476 out of 8,257 foods listed in the FCT of the U.S., representing MD specified in 42% of the foods. The FCT of New Zealand listed MD in 2,423 out of 2,631 foods, indicating MD specified in 92% of the foods. The mode of MD was 1.0, with the bimodal peaks at 0.2 and 0.6. Low MD (around 0.1–0.2) was shown in such foods as breakfast cereals or potato chips, while high MD (1.3) was found in such foods as honey or syrup. MD varied depending on how vegetables were cut, or on the physical forms for meat or cheese, even with the same food.
Conclusions The study results have suggested that MD can be standardized as 1.0 in soup, steak, fish, or fruits, all having no interspace, approximately 0.6 to 0.8 in dishes composed of ingredients of approximately 2-cm cube with interspaces, and approximately 0.3 in dishes containing air spaces such as shredded cabbage. Although challenges exist, such as discrepancies of MD in both countries, it seems meaningful to prepare standardized MD as dietary assessment tool in Japan.
