Measurement characteristics of 2 different self-monitoring tools used in adietary intervention study

Objective To examine the measurement characteristics of 2 self-monitoring t ools, a food diary and fat scan, used in the dietary intervention of the Wo men's Health Trial: Feasibility in Minority Populations study. Design Comparison of fat intake reported on the self-monitoring tools to a criterion measure of fat intake, specifically the mean of a food frequency questionnaire and a 4-day food record. The main outcome measures were diffe rences in fat grams and correlations between each of the self-monitoring to ols and the criterion measure. Subjects/setting Six-month post randomization data from 313 women aged 50 t o 79 years who participated in the intervention group of the Women's Health Trial: Feasibility in Minority Populations study. Results Both self-monitoring tools underestimated fat intake compared to th e criterion measure, the food diary by 9 g and the fat scan by 6 g. The sel f-monitoring instruments were better than chance at detecting a love-fat di etary pattern, however, and did not differ from each other in their ability to do so. Applications/conclusions The self-monitoring tools were modestly precise as measures of fat intake, but neither was sufficiently accurate to be reliab le as a sole assessment of dietary adherence. Dietetics professionals are e ncouraged to assess the measurement. properties of self-monitoring tools to use them appropriately in supporting dietary changes.