Use of a “Contract for Change” To Evaluate the Effectiveness of Nutrition Education to Increase Fruit and Vegetable Consumption in Low-Income Women

Year: 2004

Research Center: Department of Nutrition at the University of California, Davis

Investigator: Steinberg, Francene M., Karrie M. Cesario-Heneman, Amy Block-Joy, Sheri Zidenberg-Cherr, Susan Donohue, Linda Garcia, Anna Martin, Diane Metz, Dorothy Smith, and Estella West

Institution: University of California, Davis

Project Contact:
Francene Steinberg
Nutrition Department
3143 Meyer Hall, One Shields Avenue
University of California
Davis, CA 95616
Phone: 530-752-0160


The rates of chronic diseases, such as cardiovascular disease, type 2 diabetes mellitus, and obesity, continue to rise in the United States. Diet is a modifiable risk factor known to significantly affect chronic disease risk. Preventative measures, including improved dietary quality of Americans, are a key focus of nutrition public policy and education. The challenge for government and nutrition educators is how to encourage at-risk populations to make positive dietary and lifestyle changes and to overcome barriers to fruit and vegetable consumption.

The purpose of this research was to determine the effectiveness of pairing personalized goal-setting exercises within community-based nutrition education programs to promote behavior change in a low-income population. It was hypothesized that through an increased sense of self efficacy, the goalsetting group would have the following outcomes:

  1. Advance within the “stages of change” model toward accepting dietary change
  2. Increase produce consumption more than the control groups
  3. Increase markers of fruit and vegetable intake more than the control groups.
This intervention targeted English-speaking, low-income women who were potential recipients of University of California Cooperative Extension (UCCE) Expanded Food and Nutrition Education (EFNEP)/ Food Stamp Nutrition Education (FSNE) programs. After recruitment, 65 women were randomly assigned to a control group or to one of the treatment groups, an “education” group, or a “contract” group. They were asked to attend four 1- hour classes over 4 weeks. The control group received the “Gateway to a Better Life” series discussing money management.

The education group received the “Food Guide Pyramid” series currently used by California EFNEP/FSNE. The contract group received the “Food Guide Pyramid” series as well, and completed a “Contract for Change” goal-setting exercise at the initial meeting. The control group was reminded of their goals at subsequent classes. The “Contract for Change” tool was adapted from previous work demonstrating its effectiveness in changing dietary behavior. Validated questionnaires assessed study participants’ readiness to make dietary changes, to determine food consumption patterns, and to estimate actual fruit and vegetable consumption. Outcome measures were assessed three times, at both pre- and post-intervention, and with a final assessment occurring 1 month after intervention to evaluate maintenance of the anticipated dietary changes. The completion rate for the full program intervention was 58 percent.

The goal-setting contract group made significantly more progress toward acceptance or readiness to increase vegetable consumption in comparison with the control group. The results for the education group were not significantly different from the other two groups. A trend toward increased vegetable consumption was observed in the contract group. Data regarding actual consumption of fruit showed a significant increase from baseline to final time points and at one-month follow-up for the contract group in comparison to the education group. Estimates of beta-cryptoxanthin and vitamin C intake (markers of fruit intake) significantly increased in the contract group, supporting these observations.

The research results demonstrate that tailored goal-setting exercises, paired with nutrition education, can be an effective tool for nutrition professionals to facilitate dietary change in a low-income population. This approach can be utilized in existing community-based education programs targeting low-income women without increasing programmatic cost, or modifying local economic or societal conditions. The California State EFNEP/FSNE program has adopted the “Contract for Change” as a tool for county educators.

Findings, however, are limited by the relatively small number of study participants, and future research should consider certain factors at the study design stage. The primary challenge in conducting the research was participant recruitment, as the original goal of 180 women from 7 counties resulted in 38 women in 5 counties. It is believed that three factors contributed to actual participation not reaching anticipated participation:

  1. The original plan was to collect blood samples as a biomarker of dietary change. However, some potential participants declined when learning about the blood draw. While the biochemical component of the study was ultimately dropped to alleviate participant concerns and streamline study procedures, considerable time had been lost in the research timetable.
  2. The study design requirement that all participants speak English reduced the participant pool, and resulted in the withdrawal of two counties.
  3. The diversity of the target populations proved to be an additional barrier to recruitment. While training sessions were held to review the study protocol to make needed changes, the protocol did not accommodate the full diversity of participants. Future use of a new curriculum might consider recruiting participants from a more homogenous area to refine the curriculum and allow more precise evaluation of its effectiveness before expanding its use to a more diverse set of participants.