Validation of a method for estimating vegetable intake using a hand scale

Abstract

Objective: To evaluate the feasibility of using the hand scale method as a simple indicator of vegetable intake based on assuming one handful of vegetables is 60 g.

Methods: A cross-sectional research design was conducted using a web questionnaire provided to healthy adults (20–70 years old) in April 2020. The diet of the subjects was studied for 3 d (2 weekdays, 1 holiday). Subjects estimated their vegetable intake using the hand scale method. The vegetable intake was also calculated by a dietitian using the photographic method. The correlation between the vegetable intake estimations derived by the two methods was verified.

Results: A total of 338 healthy subjects (168 males, average age 44.3 years; 170 females, average age 44.9 years) who answered all questions were included in the analysis (effective response rate: 67.3%). The correlation coefficient of the mean vegetable intake estimated by the two methods was 0.63 (P<0.001), indicating a significant positive correlation. On the other hand, the vegetable intake estimated by the hand scale method was significantly lower than that by the photographic method (P<0.001), suggesting that the vegetable intake estimated by the hand scale method would be underestimated.

Conclusion: Our findings suggest that the hand scale method could be used to estimate vegetable intake. However, the hand scale method was suggested to underestimate vegetable intake. Thus, further study is needed to quantitatively measure the ability of the hand scale method to estimate vegetable intake.