Eating a diet high in fats and low in fruits and vegetables is linked to an increased risk for cardiovascular disease and cancer, as well as other chronic diseases. A review of the evidence published since 1975 regarding behavioral interventions to reduce fat and increase fruit and vegetable intake revealed that more than three-fourths of the studies on behavioral interventions (17 of the 22 reporting results of fruit and vegetable intake) reported significant increases in fruit and vegetable intake, with an average increase of 0.6 servings of fruits and vegetables per day. In addition, there were consistent decreases in intake of saturated fat and total fat (7.3 percent reduction in the percentage of calories from fat).
The study was conducted by researchers at the Research Triangle Institute-University of North Carolina at Chapel Hill Evidence-based Practice Center (EPC), which is supported by the Agency for Healthcare Research and Quality (contract 290-97- 0011). The EPC is directed by Kathleen N. Lohr, Ph.D.
Most of the behavioral interventions reviewed seemed more successful at improving the dietary behavior of people at risk of developing or already diagnosed with chronic diseases than that of generally healthy individuals. Among the specific strategies employed, goal setting and small group sessions appeared to be the most promising behavioral interventions to modify dietary behavior. Other behavioral change strategies included use of the family (for example, family homework assignments or involving spouses in cooking classes), social support, interactive activities involving food (for example, taste testing and cooking classes), and dietary guidelines tailored specifically to cultural or ethnic preferences.
Despite the lack of similarity across studies in outcome measures, study design, analysis strategy, and intervention technique, the large proportion of studies showing favorable outcomes in varied situations is promising, conclude the researchers.
See "The efficacy of behavioral interventions to modify dietary fat and fruit and vegetable intake: A review of the evidence," by Alice S. Ammerman, Dr.P.H., R.D., Christine H. Lindquist, Ph.D., Dr. Lohr, and James Hersey, Ph.D., in Preventive Medicine 35, pp. 25-41, 2002.
Editor's Note: Copies of AHRQ Evidence Report No. 25, The Efficacy of Interventions to Modify Dietary Behavior Related to Cancer Risk, Volume 1. Evidence Report and Appendixes (AHRQ Publication No. 01-E029) and Volume 2. Evidence Tables (AHRQ Publication No. 01-E029), as well as a summary of the report (AHRQ Publication No. 01-E028) are available from the AHRQ Publications Clearinghouse.
Inconsistencies in the design and reporting of research studies were a major impediment in synthesizing the evidence on dietary interventions and hampered the researchers' ability to draw broad conclusions about the most effective interventions. A new fact sheet produced by AHRQ and the National Cancer Institute offers recommendations for researchers regarding the design and reporting of studies that assess interventions to promote dietary change.
Select to access the NCI fact sheet (PDF File, 54 KB).