Importance: Unhealthful dietary patterns, low levels of physical activity, and high sedentary time increase the risk of cardiovascular disease.
Objective: To synthesize the evidence on benefits and harms of behavioral counseling interventions to promote a healthy diet and physical activity in adults without known cardiovascular disease (CVD) risk factors to inform a US Preventive Services Task Force recommendation.
Data sources: MEDLINE, PsycINFO, and the Cochrane Central Register of Controlled Trials through February 2021, with ongoing surveillance through February 2022.
Study selection: Randomized clinical trials (RCTs) of behavioral counseling interventions targeting improved diet, increased physical activity, or decreased sedentary time among adults without known elevated blood pressure, elevated lipid levels, or impaired fasting glucose.
Data extraction and synthesis: Independent data abstraction and study quality rating and random effects meta-analysis.
Main outcomes and measures: CVD events, CVD risk factors, diet and physical activity measures, and harms.
Results: One-hundred thirteen RCTs were included (N = 129 993). Three RCTs reported CVD-related outcomes: 1 study (n = 47 179) found no significant differences between groups on any CVD outcome at up to 13.4 years of follow-up; a combined analysis of the other 2 RCTs (n = 1203) found a statistically significant association of the intervention with nonfatal CVD events (hazard ratio, 0.27 [95% CI, 0.08 to 0.88]) and fatal CVD events (hazard ratio, 0.31 [95% CI, 0.11 to 0.93]) at 4 years. Diet and physical activity behavioral counseling interventions were associated with small, statistically significant reductions in continuous measures of blood pressure (systolic mean difference, -0.8 [95% CI, -1.3 to -0.3]; 23 RCTs [n = 57 079]; diastolic mean difference, -0.4 [95% CI, -0.8 to -0.0]; 24 RCTs [n = 57 148]), low-density lipoprotein cholesterol level (mean difference, 2.2 mg/dL [95% CI, -3.8 to -0.6]; 15 RCTs [n = 6350]), adiposity-related outcomes (body mass index mean difference, -0.3 [95% CI, -0.5 to -0.1]; 27 RCTs [n = 59 239]), dietary outcomes, and physical activity at 6 months to 1.5 years of follow-up vs control conditions. There was no evidence of greater harm among intervention vs control groups.
Conclusions and relevance: Healthy diet and physical activity behavioral counseling interventions for persons without a known risk of CVD were associated with small but statistically significant benefits across a variety of important intermediate health outcomes and small to moderate effects on dietary and physical activity behaviors. There was limited evidence regarding the long-term health outcomes or harmful effects of these interventions.