Improved accuracy of estimating food quantities up to 4 weeks after training.

Subjects from a large introductory nutrition course were divided into two groups, one that received training on estimating food quantities and one that received no instruction. Training consisted of 10-minute sessions during which subjects passed around and viewed 10 food models labeled with their respective quantities. The trained subjects estimated quantities of six real foods at one of three points in time: immediately after training, 1 week later, or 4 weeks later. Untrained subjects estimated quantities of the same six foods. For all foods combined, trained subjects gave significantly better estimates than untrained subjects, whether estimates were made immediately after training, 1 week later, or 4 weeks later. The estimates of the trained subjects on the day of training and 1 week later were not significantly different, but both were significantly better than estimates made 4 weeks later. In regard to individual food items, trained subjects estimating immediately or 1 week later were always more accurate than untrained subjects. Effects of training disappeared by week 4 for three of the six foods. These results support the use of training, with food models, to improve an individual's ability to estimate food quantities accurately and indicate that the impact of such training lasts for at least 1 week and can last up to 4 weeks. The findings imply that training with periodic reviews may be necessary in a clinical setting to ensure that patients estimate their food consumption accurately.