Intakes of dark green leafy, yellow/orange, cruciferous vegetables, and tomatoes (target vegetables), and involvement in physical activity have been shown to be protective actions against chronic diseases. Low-income individuals generally consume lower amounts of these target vegetables, engage in less physical activities, and experience higher incidences of chronic diseases. The study evaluated the effectiveness of a critical thinking approach in increasing (a) knowledge, (b) positive attitudes, (c) critical thinking skills of low-income parents related to vegetable offerings and physical activity, (d) the number of target vegetables low-income parents offer their children, and (e) the amount of time spent on physical activities in low-income children.

A two group randomized pretest posttest design was used. Participants were recruited from Drake University Head Start in Polk County, Iowa. The experimental group was exposed to two 45-minute sessions on vegetables and physical activity, one session per week, for two consecutive weeks. Sessions consisted of presentation of research findings on vegetables and physical activities, collaborative problem solving, goal setting, and recipe preparation. Participants in the control group did not receive any treatment.

A researcher developed questionnaire measured demographic information and the dependent variables knowledge, attitude, and critical thinking related to vegetables and physical activity, vegetable offering recall, and physical activity recall. Critical thinking scenarios and open-ended questions were used to measure participants' critical thinking abilities. The instrument was tested for face and content validity and interrater reliability. Cronbach's alpha for attitude and critical thinking ranged from .63 to .96.

Data were analyzed using descriptive statistics, ANCOVA, and content analysis. Most parents were Caucasian, female, between the ages of 19 and 39, and had a high school or above education. As a result of the critical thinking instructional approach, significant differences were observed between the experimental and control groups in offerings of the target vegetables, and total physical activities in which they engaged their children. No significant differences in positive attitudes and critical thinking related to vegetable intake and physical activities were observed. Future studies should be of longer duration, use larger sample sizes, and compare the effectiveness of the critical thinking approach with other educational approaches.