Determinants of accuracy in estimating the weight and volume of commonly used foods: A cross-cultural comparison

Inaccuracy of dietary self-reports may result from an inability to estimate portion sizes of foods. To determine the influence of cultural factors, 16 2 subjects at three study locations in rural India and 100 subjects in Mass achusetts, USA were asked to estimate weights and volumes of four commonly used food items. Compared with their Massachusetts counterparts, subjects i n India evinced errors in their estimates of food weights which averaged on ly about 20% as large, with standard deviations less than half as large. In the combined data from the four study locations, relative to those with ju st primary education, individuals with some college overestimated the small and large reference weights by 79% and 52%, respectively (p < 0.01). Impli cations of this research, including the use of quantitative dietary assessm ent methods in low literacy populations with relatively little formal educa tion and possibilities of bias in epidemiologic studies, are discussed.