In this study the transtheoretical model for behavior change was applied to the consumption of fruits, vegetables, and grain products among young adults. The criterion behavior was the consumption of the recommended number of servings described in the United States Department of Agriculture Food Guide Pyramid. Three major constructs---stages of consumption, decisional balance, and self-efficacy---were used. Specific objectives were: develop and validate an instrument to measure the three constructs; use it to measure consumption for fruits, vegetables, and grain products among young adults; examine relationships among the three constructs and among all variables; make recommendations for nutrition education and research. Measuring scales were developed for the decisional balance and self-efficacy constructs. A stage of consumption algorithm was used to assess the stages of consumption. From 800 surveys mailed to a randomly selected sample of young adults, 18 to 24 years old, 116 usable (14.5%) questionnaires were returned. Factor and reliability analyses were conducted to assess the psychometric properties of the instrument. Decisional balance emerged as two factors---the positive and negative perceptions of increasing consumption. Self-efficacy emerged as one general factor. Confirmatory factor analysis indices confirm that the data fit the hypothesized model adequately for the three food groups (AGFI > 0.80). The instrument exhibited moderate to excellent internal consistency for perceived advantages (=0.47 to 0.63), perceived disadvantages (>0.70), and self-efficacy scales (>0.88). The results of multivariate analysis of variance indicate that decisional balance and self-efficacy scores differ as stages of consumption change. The perceived advantages and self-efficacy scores increased while scores on perceived disadvantages decreased from precontemplation to maintenance stages with the exception of the action stage for fruits and grain products. For grain products, scores on the perceived disadvantages increased, with a corresponding decrease in scores for perceived advantages at the action stage. Hispanic origin, gender, race, current relationship status, and living arrangements were significant predictors of either decisional balance and/or self-efficacy among young adults. The results have implications for nutrition education and research.