Counseling to promote a healthy diet in adults: a summary of the evidence for the U.S. Preventive Services Task Force.

OBJECTIVE: The purpose of this study was to examine the effectiveness of counseling to promote a healthy diet among patients in primary care settings. DESIGN AND DATA SOURCES: We conducted a MEDLINE search from 1966 to December 2001. STUDY SELECTION: We included randomized controlled trials of at least 3 months' duration with measures of dietary behavior that were conducted in patient populations similar to those found in primary care practices. We excluded studies that reported only biochemical or anthropomorphic endpoints, had dropout rates greater than 50%, or enrolled patients based on the presence of a chronic disease. DATA EXTRACTION: One author extracted relevant data from each included article into evidence tables. Using definitions developed by the research team, two authors independently rated each study in terms of its effect size, the intensity of its intervention, the patient risk level, and the use of well-proven counseling techniques. DATA SYNTHESIS: We identified 21 trials for use in this review. Dietary counseling produces modest changes in self-reported consumption of saturated fat, fruits and vegetables, and possibly dietary fiber. More-intensive interventions were more likely to produce important changes than brief interventions, but they may be more difficult to apply to typical primary care patients. Interventions using interactive health communications, including computer-generated telephone or mail messages, can also produce moderate dietary changes.
CONCLUSIONS: Moderate- or high-intensity counseling interventions, including use of interactive health communication tools, can reduce consumption of saturated fat and increase intake of fruit and vegetable. Brief counseling of unselected patients by primary care providers appears to produce small changes in dietary behavior, but its effect on health outcomes is unclear.